WO2004033725A2 - Methods and means for the treatment of inflammatory disorders involving genotyping of the 5, 10- methylenetetrahydrofolate reductase (mthfr) gene - Google Patents

Abstract

This invention relates to the treatment of individuals with inflammatory disorders and, in particular, to methods for predicting whether inflammatory disorders are responsive to treatment with folic acid by determining whether the individual has one or both of the polymorphisms C677T and A1298C in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene.

Description

Methods and Means for the Treatment of Inflammatory Disorders

The present invention relates to the treatment of inflammatory disorders, in particular inflammatory skin disorders, and the use of genotyping to identify individuals having such disorders who are responsive to particular treatments.

Conventional treatments for skin problems and inflammatory disorders are limited and often have severe side effects. For example, methotrexate (MTX) has a number of side effects, including severe bone marrow depression, hepatotoxicicity, fibrosis and cirrhosis.

The long-term use of conventional anti-inflammatory drugs is limited and they are often unsuitable for children or pregnant women. Furthermore, responses may differ between individuals due to variations in the transport of drugs into cells.

5, 10-methylenetetrahydrofolate reductase (MTHFR) is an enzyme involved in folic acid metabolism which is active in the folate-dependent methylation of DNA precursors. Low activity of this enzyme leads to an increase of uracil incorporation into DNA (instead of thymine) (Ames, B. N. PNAS USA 96(22): 12216-12218, 1999) . The MTHFR gene is polymorphic and has been linked to colon cancer, adult acute lymphocytic leukaemia and infant leukaemia (Ames, 1999 supra; Perera, F.P et al Carcinogenesis 21 (3): 517-524, 2000.; Potter, J. D. J. Nat. Cancer Instit. 91(11): 916-932, 1999). MTHFR encoding nucleic acid is further described in US6074821. Known polymorphisms within the MTHFR locus include C677T and A1298C substitutions.

The C677T polymorphism of MTHFR results in the insertion of a valine residue in place of an alanine residue in the enzyme which lowers both the stability and the activity of the enzyme as measured in cell extracts (Frosst et al (1995) Nat. Genet. 10(1) 111-113). The A1298C polymorphism results in the insertion of a glutamate in place of an alanine residue (Viel et al (1997) Br. J. Cancer 75(8) 1105-1110) and may effect enzyme regulation by S-adenosylmethioinine ( eisberg et al (2001) 156(2) 409-415) .

Examination of population frequency of the C677T polymorphism in various ethnic groups reveals a range of approximately 10% in African populations, 15% in African American populations, 35% in American Caucasian populations, up to 45% in Italian populations (Botto et al (2000) Am. J. Epidemiol. 151(9) 862- 877). The homozygous TT genotype occurs in approximately 10% of the Caucasian population (Frosst 1995 supra) , this figure has remained consistent in later studies (reviewed in Botto (2000) supra) . The first report of the A1298C polymorphism was in 1997, and the population frequency data is much more limited; however, in Caucasian populations the frequency appears to be similar to that of the C677T allele, at approximately 30% (reviewed in Botto et al (2000) supra) .

The C677T and A1298C polymorphisms can occur together; however, not in a homozygous state for both polymorphisms. A comparative study of genotypes of neonatal cord blood and nonviable fetal tissue revealed that 677TT with 1298CC was only found in nonviable fetal tissue as was 677CT with 1298CC, suggesting a decreased viability among foetuses with these genotypes and a possible selection disadvantage with increasing number of mutant MTHFR alleles (Isotalo et al (2000) Mol. Diagn. 5(1) 59-66). The present inventors have recognised that inflammatory disorders in individuals who are polymorphic for C677T and/or A1298C of the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene are responsive to treatment involving the administration of folic acid.

One aspect of the invention provides a method of assessing an individual having an inflammatory disorder, the method comprising; determining the presence or absence of one or both of the polymorphisms C677T and A1298C, or of haplotypes in linkage disequilibrium with one or both of said polymorphisms, in the MTHFR sequence of a nucleic acid sample obtained from said individual .

A method may further comprise inferring from the presence of one or both of said polymorphisms or haplotypes that said individual responds to treatment comprising administration of folic acid or compounds which promote the activity or expression of MTHFR.

An individual who is responsive to the administration of folic acid may be heterozygous at 677 (TC) and wild-type at 1298 (AA) , wild-type at 677 (CC) and heterozygous at 1298 (AC), heterozygous at both 677 (TC) and 1298 (AC) , homozygous at

677 (TT) and wild-type at 1298 (AA) , homozygous at 677 (TT) and heterozygous at 1298 (AC) , wild type at 677 (CC) and homozygous at 1298 (CC) , heterozygous at 677 (TC) and homozygous at 1298 (CC) or homozygous at 677 (TT) and 1298 (CC) .

A nucleic acid sample suitable for use in such a method may be an RNA or DNA sample isolated from any suitable client or patient cell sample, for example a genomic DNA sample, or an amplification product of such a nucleic acid. For convenience, it is preferred that the DNA is isolated from cheek (buccal) cells. This enables easy and painless collection of cells.

The term ^λfolic acid' as used herein may include folic acid, and derivatives, metabolites and prodrugs of folic acid.

Cells may be isolated from the inside of the mouth using a disposable scraping device with a plastic or paper matrix ^brush", for example, the C.E.P. Swab™ (Life Technologies

Ltd., UK) . Cells are deposited onto the matrix upon gentle abrasion of the inner cheek, resulting in the collection of approximately 2000 cells (Aron, Y. et al (1994) Allergy 49 (9) : 788-90) . The paper brush can then be left to dry completely, ejected from the handle placed into a micro- centrifuge tube for storage prior to analysis.

DNA from the cell samples may be isolated using conventional procedures. For example DNA may be immobilised onto filters, column matrices, or magnetic beads. Numerous commercial kits, such as the Qiagen QIAamp kit (Qiagen, Crawley, UK) may be used. Briefly, the cell sample may be placed in a microcentrifuge tube and combined with Proteinase K, mixed, and allowed to incubate to lyse the cells. Ethanol is then added and the lysate is transferred to a QIAamp spin column from which DNA is eluted after several washings.

The amount of DNA isolated by the particular method used may be quantified to ensure that sufficient DNA is available for the assay and to determine the dilution required to achieve the desired concentration of DNA for PCR amplification. For example, the desired target DNA concentration may be in the range 10 ng and 50 ng. DNA concentrations outside this range may impact the PCR amplification of the individual alleles and thus impact the sensitivity and selectivity of the polymorphism determination step.

The quantity of DNA obtained from a sample may be determined using any suitable technique. Such techniques are well known to persons skilled in the art and include UV (Maniatis T., Fritsch E. F. , and Sambrook J., (1982) Molecular Cloning A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Springs Harbor, NY) or fluorescence based methods. As UV methods may suffer from the interfering absorbance caused by contaminating molecules such as nucleotides, RNA, EDTA and phenol and the dynamic range and sensitivity of this technique is not as great as that of fluorescent methods, fluorescence methods are preferred. Commercially available fluorescence based kits such as the PicoGreen dsDNA Quantification (Molecular Probes, Eugene, Oregon, USA) .

Prior to the testing of a sample, the nucleic acids in the sample may be selectively amplified, for example using

Polymerase Chain Reaction (PCR) amplification, as described in U.S. patent numbers 4,683,202 and 4,683,195.

Preferred primers for use in the present invention are from 18 to 23 nucleotides in length, without internal homology or primer-primer homology.

Furthermore, to ensure amplification of the region of interest and specificity, the two primers of a pair are preferably selected to hybridise to either side of the region of interest so that about 150 bases in length are amplified, although amplification of shorter and longer fragments may also be used. Ideally, the site of polymorphism should be at or near the centre of the region amplified.

Preferred examples of primer pairs which may be used for analysing the C677T and A1298C polymorphisms in the MTHFR gene are shown in Table 1, together with preferred examples of the wild-type probes and polymorphic probes used in the Taqman® assay for each gene target.

Having obtained a sample of DNA, preferably with amplified regions of interest, the individual polymorphisms may be identified. Identification of the markers for the polymorphisms involves the discriminative detection of allelic forms of the MTHFR gene that differ by nucleotide substitution at position 677 and/or 1298.

Methods for the determining the presence of known nucleotide differences are well known to the skilled person. These may include, but are not limited to:

- Hybridization with allele-specific oligonucleotides (ASO) , (Wallace, R. B. et al (1981) Nucleic Acids Research. 9:879- 894; Ikuta, S. et al (1987) Nucleic Acids Research. 15:797- 811; Nickerson, D. et al(1990) PNAS USA 87:8923-8927, Verlaan- de Vries, M et al (1986) Gene. 50:313-320, Saiki, R. K. et al (1989) PNAS. USA 86:6230-6234 and Zhang, Y. et al (1991) Nucleic Acids Research. 19: 3929-3933)

- Allele specific PCR, (Newton, C. R. et al (1989) . Nucleic Acids Research. 17:2503-2516, Gibbs, R. A. et al (1989)

Nucleic Acids Research. 17:2437-2448). - Solid-phase minisequencing (Syvanen, A. C. et al(1993) Am. J. Human Genet. 52:46-59).

- Oligonucleotide ligation assay (OLA) (Wu, D. Y., et al (1989) Genomics. 4:560-569, Barany, F. (1991) PNAS USA 88:189- 193, Abravaya, K. et al 1995. Nucleic Acids Research. 23:675- 682) .

- The 5' fluorogenic nuclease assay (Lee, E. et al J. Toxicol. Soc. 23: 140-142, (1998), US4, 683,202, US4,683,195, US5,723,591 and US5, 801, 155) .

- Restriction fragment length polymorphism (RFLP) , (Donis- Keller H. et . al . (1987) Cell, 51, 319-337).

In a preferred embodiment, the polymorphisms in the MTHFR locus may be assessed via a specialised type of PCR used to detect polymorphisms, commonly referred to as the Taqman® assay and performed using an AB7700 instrument (Applied Biosystems, Warrington, UK) . In this method, a probe is synthesised which hybridises to a region of interest containing the polymorphism. The probe contains three modifications: a fluorescent reporter molecule, a fluorescent quencher molecule and a minor groove-binding chemical to enhance binding to the genomic DNA strand. The probe may be bound to either strand of DNA. For example, in the case of binding to the coding strand, when the Taq polymerase enzyme begins to synthesise DNA from the 5' upstream primer, the polymerase will encounter the probe and begin to remove bases from the probe one at a time using a 5' -3' exonuclease activity. When the base bound to the fluorescent reporter molecule is removed, the fluorescent molecule is no longer quenched by the quencher molecule and the molecule will begin to fluoresce. This type of reaction can only take place if the probe has hybridised perfectly to the matched genomic sequence. As successive cycles of amplification take place, i.e. more probes and primers are bound to the DNA present in the reaction mixture, the amount of fluorescence will increase and a positive result will be detected. If the genomic DNA does not have a sequence that matches the probe perfectly, no fluorescent signal is detected.

In a preferred embodiment of the invention, hybridisation with allele specific oligonucleotides is conveniently carried out using oligonucleotide arrays, preferably microarrays, to determine the presence of a particular polymorphism.

Such microarrays allow miniaturisation of assays, e.g. making use of binding agents (such as nucleic acid sequences) immobilised in small, discrete locations (microspots) and/or as arrays on solid supports or on diagnostic chips. These approaches may provide great sensitivity (particularly through the use of fluorescent labelled reagents) , require only very small amounts of biological sample from individuals being tested and allow a variety of separate assays to be carried out simultaneously. This latter advantage can be useful as it provides an assay for different a number of polymorphisms of one or more genes to be carried out using a single sample.

Examples of techniques enabling this miniaturised technology are provided in WO84/01031, WO88/1058, WO89/01157, W093/8472, W095/18376/ W095/18377, W095/24649 and EP-A-0373203, the subject matter of which are herein incorporated by reference.

DNA microarrays have been shown to provide appropriate discrimination for polymorphism detection (Yershov, G. et. al.(1996) PNAS USA, Genetics, Vol. 93, 4913-4918; Schena, M., 1999, DNA Microarrays "a practical approach", ISBN, 0-19- 963777-6, Oxford press, editor B. D. Hames; Cheung, V. G., et. al., 1999, Nat. Genet., vol. 21, 15-19). In brief, the DNA microarray may be generated using oligonucleotides that have been selected to hybridise with the specific target polymorphism. These oligonucleotides may be applied by a robot onto a predetermined location of a glass slide, e.g. at predetermined X, Y cartesian coordinates, and immobilised. The PCR product (e.g. fluorescently labelled RNA or DNA) is introduced on to the DNA microarray and a hybridisation reaction conducted so that sample RNA or DNA binds to complementary sequences of oligonucleotides in a sequence- specific manner, and allow unbound material to be washed away. Gene target polymorphisms can thus be detected by their ability to bind to complementary oligonucleotides on the array and produce a signal. The fluorescence at each coordinate can be read using a suitable automated detector in order to correlate each fluorescence signal with a particular oligonucleotide. The absence of a fluorescent signal for a specific oligonucleotide probe indicates that the client does not have the corresponding polymorphism. Of course, the method is not limited to the use of fluorescence labelling but may use other suitable labels known in the art.

Oligonucleotides for use in the array may be selected to span the site of the polymorphism, each oligonucleotide comprising one of the following at a central location within the sequence :

- wild-type or normal base at the position of interest in the leading strand

- wild-type or normal base at the position of interest in the lag (non-coding) strand - altered base at the position of interest in the leading strand

- altered complementary base at the position of interest in the lag strand

An inflammatory condition in an individual may thus be assessed using one or more oligonucleotides as described herein. Such nucleotides may, in some embodiments, be provided on a microarray.

A suitable inflammatory disorder may include any disorder in which a reduction in inflammation is desirable, including an inflammatory skin disorder such as atopic dermatitis, contact dermatitis, eczema, psoriasis and other inflammatory disorders such as Perianal Crohn' s disease and rheumatoid arthritis.

An individual identified by a method according to this aspect of the invention may be responsive to folic acid, or derivatives, metabolites or pro-drugs thereof. Such an individual may also be responsive to compounds which either promote or reduce the activity or expression of MTHFR, including, for example, FAD, riboflavin, folic acid and vitamin B6.

The ability of an individual to respond to folic acid may also be affected by defects or variations in antioxidant metabolism.

A method may comprise the further step of determining the presence of polymorphisms in one or more of the following oxidation associated genes in said individual; methionine synthase, cystathionine β synthase, vitamin D receptor, collagen type 1 alpha gene, tumour necrosis factor c. and β, glutathione S-transferase, cytochro e p450 1A1 and 1A2, manganese superoxide dismutase, extracellular superoxide dismutase, epoxide hydrolase, myeloperoxidase, nitric oxide synthase, glutathione peroxidase, interleukin 10, interleukin 6 and selenoproteins .

For example, the presence of one or more of the polymorphisms set out in Table 2 may be determined.

Methods of determining the presence of a polymorphism at a particular position within a gene or locus are described above .

In some embodiments, a method may comprise the further step of administering folic acid to the individual. Folic acid may be administered alone or in combination with one or more of vitamin B12/B6 and antioxidants, for example vitamin C, vitamin E, lycopene, beta-carotene and minerals such as magnesium, manganese, selenium and zinc.

Administration may be in the form of a medicament such as a tablet or pill, which, for example comprises the active ingredient and a suitable excipient, or in the form of a foodstuff rich in folic acid and, optionally, vitamin B and/or antioxidants, such as, for example, vitamin C as described above .

A method may comprise the further step of providing a dietary regime for said individual comprising foodstuffs comprising elevated levels of one or more of folic acid, vitamin B6/B12 and/or antioxidants. Foodstuffs with elevated levels of folic acid include beef, lamb, pork, chicken liver, deep green leafy vegetables, asparagus, broccoli, wheat bran and yeast.

Foodstuffs with elevated levels of vitamin B12 include red meat, poultry, eggs, dairy products, yeast extract, and some soya products .

Foodstuffs with elevated levels of vitamin B6 include poultry, fish, eggs, spinach, carrots, and wheatgerm.

An elevated level of a nutrient is generally considered to be at least lOOμg nutrient per lOOg of foodstuff.

Another aspect of the invention provides the use of composition comprising folic acid in the manufacture of a medicament for use in the treatment of an inflammatory disorder in an individual who is polymorphic for one or both of the C677T and A1298C polymorphisms in the MTHFR locus.

Inflammatory disorders are described above. In some embodiments the treatment of psoriasis and/or Crohn's disease may be excluded.

The individual may have a polymorphism in one or more of the oxidation associated genes described above.

As described above, the composition may further comprise vitamin B6/B12 and/or an antioxidant such as vitamin C.

The term "treatment" as used herein in the context of treating a condition, pertains generally to treatment and therapy, whether of a human or an animal (e.g. in veterinary applications) , in which some desired therapeutic effect is achieved, for example, the inhibition of the progress of the inflammatory condition, and includes a reduction in the rate of progress, a halt in the rate of progress, amelioration of the inflammatory condition, and cure of the inflammatory condition. Treatment as a prophylactic measure (i.e. prophylaxis) is also included.

The term ^xAherapeutically-effective amount" as used herein, pertains to that amount of an active compound, or a material, composition or dosage from comprising an active compound, which is effective for producing some desired therapeutic effect, commensurate with a reasonable benefit/risk ratio.

Folic acid or a pharmaceutical composition comprising folic acid, folic salts, pro-drugs and metabolites of folic acid, may be administered to a subject by any convenient route of administration, whether systemically/ peripherally or at the site of desired action, including but not limited to oral (e.g. by ingestion) or, more preferably, topical (including e.g. transdermal, intranasal, ocular, buccal, and sublingual) .

The subject may be a eukaryote, an animal, a vertebrate animal, a mammal, a rodent, murine, canine, feline, equine bovine, ovine or human.

While it is possible for the folic acid and, optionally, other active compounds such as vitamin B6/B12, to be administered alone, it is preferable to present them as a pharmaceutical composition (e.g. formulation) comprising at least one active compound, as defined above, together with one or more pharmaceutically acceptable carriers, adjuvants, excipients, diluents, fillers, buffers, stabilisers, preservatives, lubricants, or other materials well known to those skilled in the art and optionally other therapeutic or prophylactic agents .

Thus, the present invention further provides pharmaceutical compositions, as defined above, and methods of making a pharmaceutical composition comprising admixing folic acid and, optionally, other active compounds such as vitamin B6/B12 and anti-oxidants, together with one or more pharmaceutically acceptable carriers, excipients, buffers, adjuvants, stabilisers, or other materials, as described herein.

The term "pharmaceutically acceptable" as used herein pertains to compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of a subject

(e.g. human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, excipient, etc. must also be "acceptable" in the sense of being compatible with the other ingredients of the formulation.

Suitable carriers, excipients, etc. can be found in standard pharmaceutical texts, for example, Remington's Pharmaceutical Sciences, 18th edition, Mack Publishing Company, Easton, Pa., 1990.

The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active compound with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active compound with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product.

Formulations may be in the form of liquids, solutions, suspensions, emulsions, elixirs, syrups, tablets, lozenges, granules, powders, capsules, cachets, pills, ampoules, ointments, gels, pastes, creams, sprays, mists, foams, lotions, oils, suppositories, boluses or sustained release formulations .

Formulations suitable for oral administration (e.g. by ingestion) may be presented as discrete units such as capsules, cachets or tablets, each containing a predetermined amount of the active compound; as a powder or granules; as a solution or suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion; as a bolus; as an electuary; or as a paste.

A tablet may be made by conventional means, e.g., compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active compound in a free-flowing form such as a powder or granules, optionally mixed with one or more binders (e.g. povidone, gelatin, acacia, sorbitol, tragacanth, hydroxypropylmethyl cellulose) ; fillers or diluents (e.g. lactose, microcrystalline cellulose, calcium hydrogen phosphate); lubricants (e.g. magnesium stearate, talc, silica) ; disintegrants (e.g. sodium starch glycolate, cross-linked povidone, cross-linked sodium carboxymethyl cellulose) ; surface-active or dispersing or wetting agents (e.g. sodium lauryl sulfate); and preservatives (e.g. methyl p-hydroxybenzoate, propyl p-hydroxybenzoate, sorbic acid) . Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active compound therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.

Formulations suitable for topical administration (e.g. transdermal, intranasal, ocular, buccal, and sublingual) may be formulated as an ointment, cream, suspension, lotion, powder, solution, past, gel, spray, aerosol, or oil. Alternatively, a formulation may comprise a patch or a dressing such as a bandage or adhesive plaster impregnated with active compounds and optionally one or more excipients or diluents .

Formulations suitable for topical administration via the skin include ointments, creams, and emulsions. When formulated in an ointment, the active compound may optionally be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active compounds may be formulated in a cream with an oil-in-water cream base. If desired, the aqueous phase of the cream base may include, for example, at least about 30% w/w of a polyhydric alcohol, i.e., an alcohol having two or more hydroxyl groups such as propylene glycol, butane-1, 3-diol, mannitol, sorbitol, glycerol and polyethylene glycol and mixtures thereof. The topical formulations may desirably include a compound which enhances absorption or penetration of the active compound through the skin or other affected areas. Examples of such dermal penetration enhancers include dimethylsulfoxide and related analogues, as well nicotine, which is known to increase blood flow to the skin.

When formulated as a topical emulsion, the oily phase may optionally comprise merely an emulsifier (otherwise known as an emulgent) , or it may comprises a mixture of at least one emulsifier with a fat or an oil or with both a fat and an oil. Preferably, a hydrophilic emulsifier is included together with a lipophilic emulsifier which acts as a stabiliser. It is also preferred to include both an oil and a fat. Together, the emulsifier (s) with or without stabiliser (s) make up the so-called emulsifying wax, and the wax together with the oil and/or fat make up the so-called emulsifying ointment base which forms the oily dispersed phase of the cream formulations.

Suitable emulgents and emulsion stabilisers include Tween 60, Span 80, cetostearyl alcohol, myristyl alcohol, glyceryl onostearate and sodium lauryl sulphate. The choice of suitable oils or fats for the formulation is based on achieving the desired cosmetic properties, since the solubility of the active compound in most oils likely to be used in pharmaceutical emulsion formulations may be very low. Thus the cream should preferably be a non-greasy, non-staining and washable product with suitable consistency to avoid leakage from tubes or other containers. Straight or branched chain, mono- or dibasic alkyl esters such as di-isoadipate, isocetyl stearate, propylene glycol diester of coconut fatty acids, isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate, 2-ethylhexyl palmitate or a blend of branched chain esters known as Crodamol CAP may be used, the last three being preferred esters. These may be used alone or in combination depending on the properties required. Alternatively, high melting point lipids such as white soft paraffin and/or liquid paraffin or other mineral oils can be used.

It will be appreciated that appropriate dosages of the active compounds, and compositions comprising the active compounds, can vary from patient to patient. Determining the optimal dosage will generally involve the balancing of the level of therapeutic benefit against any risk or deleterious side effects of the treatments of the present invention. The selected dosage level will depend on a variety of factors including, but not limited to, the activity of the particular compound, the route of administration, the time of administration, the rate of excretion of the compound, the duration of the treatment, other drugs, compounds, and/or materials used in combination, and the age, sex, weight, condition, general health, and prior medical history of the patient. The amount of compound and route of administration will ultimately be at the discretion of the physician, although generally the dosage will be to achieve local concentrations at the site of action that achieve the desired effect without causing substantial harmful or deleterious side-effects .

Administration in vi vo can be effected in one dose, continuously or intermittently (e.g. in divided doses at appropriate intervals) throughout the course of treatment. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used for therapy, the purpose of the therapy, the target cell being treated, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician.

In general, a suitable dose of folic acid or its analogue is in the range of about 200 μg to about 5 mg per day, more preferably about 800μg per day. This may be in the form of a single bolus dose or more preferably in multiple applications or a sustained release preparation.

Folic acid has poor oral bio-availability in some individuals (Molloy, A.M. Int J Vita Nutr Res. 2002 Jan; 72 (1 ): 46-52, Zarazaga A, et al Nutr Hosp 1991 Jul-Aug; 6 (4) : 207-266) , in particular the elderly, people living at poverty level, women taking the birth control pill and people suffering from certain diseases, including Liver disease, alcoholism and malabsorption syndromes.

Furthermore, oral administration of folic acid can mask the symptoms of vitamin B12 deficiency and lead to long-term complications. Folic acid is, however, poorly absorbed through the skin.

The present inventors have discovered that the absorption of folic acid through the skin is significantly enhanced by binding to folate binding protein (FBP) . Topical formulations comprising both of these components are therefore useful in the treatment of inflammatory skin conditions.

Another aspect of the invention provides a composition comprising folic acid and folate binding protein (FBP) in a topical formulation for use in a method of treatment of the human or animal body. Folate binding protein is preferably human folate binding protein (FBP) (Swiss-Prot: P15328) . FBP may be produced by recombinant expression of encoding nucleic acid using conventional techniques, followed, if desired, by the isolation and/or purification of the expressed polypeptide.

A topical formulation may comprise a dermal penetration enhancer and/or a paraffinic or a water-miscible ointment base and/or liposomes and liposomes covalently attached to proteins (Betageri G et al Liposome Drug Delivery Systems' (1993) ISBN 1-56676-030-5; New, R. Liposomes-a practical approach' Oxford University Press (1990) ISBN 0-19-963076-3) . The ointment base, which forms the oily dispersed phase of the cream formulations, may comprise oil and/or fat and an emulsifying wax comprising an emulsifier (s) with or without stabiliser (s) . Such formulations are further described above.

Preferably the pH of said formulation is between pH 6.5 and pH 7.5, more preferably about pH 7.

Another aspect of the invention provides the use of a composition comprising folic acid and folate binding protein (FBP) in the manufacture of a medicament for topical application in the treatment of an inflammatory disorder.

A method of producing such a composition may comprise admixing folic acid and folate binding protein with a pharmaceutically acceptable carrier, such as sesame or other oils, liposomes or cyclodextrins, and, optionally, an ointment base as described above.

As described above, the inflammatory disorder may be an inflammatory skin disorder, such as atopic dermatitis, contact dermatitis (allergic and irritant) , eczema, psoriarsis, Crohn' s disease or rheumatoid arthritis.

An individual having such a disorder who is suitable for treatment with such topical compositions may be polymorphic for one or both of the C677T and A1298C polymorphisms in the MTHFR locus.

The present inventors have observed that folic acid has an anti-inflammatory effect. Contrary to the prevailing view in the art, this indicates that anti-inflammatory factors are generated by members of the folic acid metabolism pathway upstream of the MTHFR enzyme.

Various aspects of the invention relate to screening methods and methods for obtaining agonists of upstream FA metabolic enzymes which enhance the production of anti-inflammatory factors/or repress pro-inflammatory factors and thus exert an anti-inflammatory effect.

An aspect of the invention provides a method of screening for an anti-inflammatory compound comprising, contacting a test compound with one or more enzymes of the folic acid metabolic pathway which act upstream of MTHFR, and; determining the activity of said one or more enzymes in the presence relative to the absence of said test compound, an increase in activity being indicative that said test compound is an anti-inflammatory compound.

An increase in activity in the presence, relative to the absence, of the test compound is indicative that the test compound enhances said activity and may therefore have an anti-inflammatory effect. Such a compound may thereby modulate i.e. increase or enhance the production of anti-inflammatory factors, for example by stimulating the folic acid metabolic pathway upstream of MTHFR.

Enzymes of the folic acid metabolic pathway which act upstream of MTHFR include dihydrofolate reductase (EC 1.5.1.3), folylpolyglutamate synthetase and thymidylate synthetase (EC 2.1.1.45) .

Activity may be determined by measuring the production of enzyme product or the depletion of enzyme substrate in the presence relative to the absence of test compound. An increase in the rate of production of product or depletion of substrate by the enzyme in the presence relative to the absence of test compound is indicative that the test compound is an agonist (i.e. an enhancer or inducer) of the enzyme.

A method may further comprise the step of determining an increase in anti-inflammatory activity in the presence of the test compound relative to the absence.

Anti-inflammatory activity may be determined using conventional methodologies.

Methods according to this aspect of the invention may be in vivo cell-based methods, or in vi tro non-cell-based methods. In vivo methods may be performed in a cell line such as a yeast strain, insect or mammalian cell line, for example CHO, HeLa or COS cells. The precise format for performing methods of the invention may be varied by those of skill in the art using routine skill and knowledge .

Of course, the person skilled in the art will design any appropriate control experiments with which to compare results obtained in methods of the invention.

Aspects of the present invention will now be illustrated with reference to the experimental exemplification and Tables below, by way of example and not limitation. Further aspects and embodiments will be apparent to those of ordinary skill in the art.

All documents mentioned in this specification are hereby incorporated herein by reference.

Examples

Preparation of DNA Sample DNA was prepared from a buccal cell sample on a brush using a Qiagen QIAamp kit according to the manufacturer's instructions (Qiagen, Crawley, UK) . Briefly, the brush was cut in half and one half stored at room temperature in a sealed tube in case retesting was required. The other half of the brush is placed in a microcentrifuge tube. 400μl PBS was added and the brush allowed to rehydrate for 45 minutes at room temperature. Qiagen lysis buffer and Proteinase K was then added, the contents mixed, and allowed to incubate at 56 C for 15 minutes to lyse the cells. Ethanol was added and the lysate transferred to a QIAamp spin column from which DNA was eluted after several washings. Quantification of DNA

In order to check that sufficient DNA has been isolated, a quantification step was carried out using the PicoGreen dsDNA Quantification kit (Molecular Probes, Eugene, Oregon, USA) .

Briefly, client DNA samples were prepared by transferring a 10 μl aliquot into a microcentrifuge tube with 90μl TE . 100 μl of the working PicoGreen dsDNA quantification reagent was added, mixed well, and transferred into a black 96 well plate with flat well bottoms. The plate was then incubated for 5 minutes in the dark before a fluorescent reading was taken. The quantity of DNA present in the sample was determined by extrapolating from a calibration plot prepared using DNA standards .

A quantity of DNA in the range of 5-50ng total was used in the subsequent PCR step. Remaining DNA sample was stored at -20°C for retesting if required.

Taqman® Assay to Identify the MTHFR A1298C polymorphism

The modified reaction mixture contained Taq polymerase (1.25 units/μl) , optimised PCR buffer, dNTP (200μM each), 2mM MgCl₂ and primer pairs SEQ ID NO: 5 and 6 and polymorphism probe SEQ ID NO: 8.

The reaction mixture was initially incubated for 10 minutes at 50°C, then 5 minutes at 95°C, followed by 40 cycles of 1 minute of annealing at between 55°C and 60°C and 30 seconds of denaturation at 95°C. Both during the cycles and at the end of the run, fluorescence of the released reporter molecules of the probe was measured by an integral CCD detection system of the AB7700 ther ocycler. The presence of a fluorescent signal which increased in magnitude through the course of the run indicated a positive result.

The assay was then repeated with the same primer pair and wild type (wt) probe SEQ ID NO: 7. If the sample is homozygous for the polymorphism, no fluorescence signal is seen with the wt probe. However, if the sample is heterozygous for the polymorphism, a fluorescence signal is also seen with the wt probe. If single reporter results from homozygous wt, homozygous polymorphic and heterozygous polymorphic samples are plotted are plotted on an X/Y axis, the homozygous alleles will cluster at opposite ends of the axes relative to each reporter, and the heterozygous alleles will cluster at a midway region.

Taqman® Assay to Identify the MTHFR C677T polymorphism The modified reaction mixture contained Taq polymerase (1.25 units/μl), optimised PCR buffer, dNTP (200μM each), 2mM MgCl₂ and primer pairs SEQ ID NO: 1 and 2 and polymorphism probe SEQ ID NO: 4. The assay was performed as described above, using SEQ ID NO: 3 as a wt probe.

Results

800μg Folic acid was administered orally to a patient group with or without 500mg vitamin C.

Six individuals with skin disorders reporting improvements in their condition following the administration.

Two of these individuals were identified as being heterozygotes for both MTHFR polymorphism C677T and A1298C. The remaining four were heterozygous for one or other of these polymorphisms . Polymorphisms at one or both of these positions are therefore indicative of responsiveness to the treatment.

Individual Case Studies

Case 1: Caucasian female, 40 years of age. History of eczema and flaky skin on hands and arms. Began taking 800μg folic acid daily upon receiving dietary advice after identification of MTHFR C677T heterozygous polymorphism. Subject reported rapid improvement of eczema symptoms after taking the folic acid supplement.

I

Case 2: Caucasian female, 25 years of age. History of severe inflammation of skin, particularly affecting hands. Genetic screening identified C677T heterozygous polymorphism.

Supplementation of daily 800μg folic acid begun, significant improvement of symptoms reported.

Case 3: Caucasian female, 21 years of age: History of eczema. Genetic screening identified C677T heterozygous polymorphism. Supplementation of daily 800μg folic acid begun, significant improvement of symptoms reported. Symptoms reappeared upon cessation of folic acid supplementation after approximately two weeks but disappeared again when folic acid supplementation resumed.

Case 4: Caucasian male, 67 years of age. History of mild eczema. Genetic screening identified C677T heterozygous and A1298C heterozygous polymorphisms Improvement of symptoms reported upon supplementation with daily 800μg folic acid.

Case 5: Caucasian female, 65 years of age. History of mild eczema. Genetic screening identified C677T heterozygous and A1298C heterozygous polymorphisms. Improvement of symptoms reported upon supplementation with daily 800μg folic acid.

Table 1

Table 2

Claims

Claims :

1. A method of assessing an individual having an inflammatory disorder, the method comprising; determining the presence of one or both of the polymorphisms C677T and A1298C, or a haplotype in linkage disequilibrium with one or both of said polymorphisms, in an MTHFR nucleic acid sequence of one or more cells obtained from said individual, and; inferring from the presence of one or both of said polymorphisms that said inflammatory disorder is responsive to treatment comprising administration of folic acid.

2. A method according to claim 1 wherein said inflammatory disorder is an inflammatory skin disorder.

3. A method wherein said disorder is selected from the group consisting of atopic dermatitis, contact dermatitis, eczema, psoriarsis and Perianal Crohn's disease.

4. A method according to any one of the preceding claims comprising the further step of determining the presence of polymorphisms in one or more of the following genes in said individual; ethionine synthase, cystathionine β synthase, vitamin D receptor, collagen type 1 alpha gene, tumour necrosis factor and β, glutathione S-transferase, cytochrome p450 1A1 and 1A2, manganese superoxide dismutase, extracellular superoxide dismutase, epoxide hydrolase, myeloperoxidase, nitric oxide synthase, glutathione peroxidase, interleukin 10, interleukin 6 and selenoproteins .

5. A method according to claim 4 wherein said polymorphism is shown in Table 2.

6. A method according to any one of claims 1 to 5 wherein said treatment comprises administration of folic acid in combination with vitamin B12/B6.

7. A method according to any one of claims 1 to 6 wherein said treatment further comprises administration of an antioxidant .

δ. A method according to claim 7 wherein said antioxidant is selected from the group consisting of vitamin C, vitamin E, beta carotene, lycopene, magnesium, manganese, zinc, selenium, guercetin and other compounds which scavenge oxidative reaction products.

9. A method according to any one of claims 1 to 8 comprising the further step of providing a dietary regime for said individual comprising foodstuffs having elevated levels of one or more of folic acid, vitamin B6/B12 and antioxidants.

10. Use of a composition comprising folic acid in the manufacture of a medicament for use in the treatment of an inflammatory disorder in an individual who is polymorphic for one or both of the polymorphisms C677T and A1298C in the MTHFR locus .

11. Use according to claim 10 wherein said inflammatory disorder is an inflammatory skin disorder.

12. Use according to claim 11 wherein said disorder is selected from the group consisting of atopic dermatitis, contact dermatitis, eczema, psoriarsis and Perianal Crohn' s disease.

13. Use according to claim 11 or claim 12 wherein said individual has a polymorphism in one or more of the following genes; methionine synthase, cystathionine β synthase, vitamin D receptor, collagen type 1 alpha gene, tumour necrosis factor and β, glutathione S-transferase, cytochrome p450 1A1 and 1A2, manganese superoxide dismutase, extracellular superoxide dismutase, epoxide hydrolase, myeloperoxidase, nitric oxide synthase, glutathione peroxidase, interleukin 10, interleukin 6 and selenoprotein genes.

14. Use according to claim 13 wherein said polymorphism is shown in Table 2.

15. Use according to any one of claims 12 to 14 wherein said composition comprises vitamin B6/B12.

16. Use according to claim 15 wherein said composition comprises an antioxidant.

17. Use according to claim 16 wherein said antioxidant is selected from the group consisting of vitamin C, vitamin E, beta carotene, lycopene, magnesium, manganese, zinc, selenium, guercetin and other compounds which scavenge oxidative reaction products.

16. Use according to any one of claims 10 to 17 wherein the treatment of psoriasis is excluded.

19. A composition comprising folic acid and/or derivatives and folic acid binding protein (FBP) in a topical formulation for use in a method of treatment of the human or animal body.

20. Use of a composition comprising folic acid and/or derivatives and folic acid binding protein (FBP) in the manufacture of a medicament for topical application in the treatment of an inflammatory disorder.

21. Use according to claim 20 wherein said inflammatory disorder is an inflammatory skin disorder.

22. Use according to claim 21 wherein said disorder is selected from the group consisting of atopic dermatitis, contact dermatitis, eczema, psoriarsis and Perianal Crohn' s disease.

23. Use according to any one of claims 20 to 22 wherein said composition comprises vitamin B6/B12.

24. Use according to claim 23 wherein said composition comprises an antioxidant.

25. Use according to claim 24 wherein said antioxidant is selected from the group consisting of vitamin C, vitamin E, beta carotene, lycopene, magnesium, manganese, zinc, selenium, guercetin and other compounds which scavenge oxidative reaction products.

26. A method of screening for a compound which promotes anti- inflammatory activity comprising, contacting a test compound with a enzyme of the folic acid metabolic pathway which acts upstream of MTHFR, determining the activity of said enzyme in the presence relative to the absence of said test compound. an increase in activity being indicative that said test compound promotes anti-inflammatory activity.

27. A method of screening for a compound which promotes anti- inflammatory activity comprising, providing a folic acid metabolic pathway, contacting a test compound with said pathway in the presence of an inhibitor of MTHFR, contacting said pathway with folic acid, and; determining the anti-inflammatory activity of said pathway.

28. A method according to claim 26 or claim 27 comprising identifying said test compound as a compound which promotes anti-inflammatory activity.

29. A method according to claim 28 comprising formulating said compound with a pharmaceutically acceptable excipient.