WO1986005099A1

WO1986005099A1 - Preparations of immunoglobulines presenting high titres of blocking antibodies

Info

Publication number: WO1986005099A1
Application number: PCT/FR1986/000075
Authority: WO
Inventors: Marion Steinbuch; Jean-Pierre Soulier; Bernard Poupot
Original assignee: Centre National De Transfusion Sanguine
Priority date: 1985-03-07
Filing date: 1986-03-07
Publication date: 1986-09-12
Also published as: EP0215081A1; JPS62502119A; FR2578425A1; FR2578425B1

Abstract

The IgG-based preparations of the invention have a titre of IgG 4 of at least 4% and a ratio of polymer chains of at least 10%, their titre in anti-pollen and anti-acarian anti-allergen antibodies being at least of 4 u/ml of preparation.

Description

Iπuαunoglobulin preparations with high titers of blocking antibodies.

The subject of the invention is preparations of immunoglobulins having in particular high titers of antiallergenic blocking antibodies, their preparation and their applications for the treatment of allergies.

Allergic manifestations are linked to the presence of antibodies of the IgE or reactin type present on the surface of the effector cells of the immunity and in the circulating blood.

These allergen-specific IgE antibodies are present at high levels in sensitized subjects. Antibodies of the IgG type directed against these same allergens exert a protective effect with respect to the anaphylactic reactions arising from the meeting of IgE and allergens. These IgG antibodies are called blocking antibodies ^* . Their presence can be demonstrated in the serum of subjects who do not have an allergic reaction. Their rate rises during desensitization cures with allergen extracts (pollens, mites, or venoms of hymenoptera), their rise being concomitant with the decrease in clinical manifests. 5

Various preparations based on IgG are currently used to reduce allergic reactions. These preparations are obtained by extraction from human plasma. The extraction method of 0 Kistler P., Nitschmann H. and Lergier. described in Helvetica Chimica Acta (1954), 37, p.866-873, modified by Kistler P. and Nitschmann H. as described in Vox Sanguinis 1962, t.7, Vol.4, P.414-424, is generally used . 5 This method, based on alcoholic fractionation, comprises adding alcohol to the plasma, up to a final alcohol concentration of 19 or 22, at a pH of 5.85.

The precipitate which forms, called the precipitate, contains the fractions I (fibrinogen, factor VIII) and II + III (IgG, factors II, VII, IX, X and the and J globulins).

The preparations based on IgG used in therapy are generally obtained from fractions II + III.

By studying this fractionation, the inventors have found that by treating under set conditions the entire precipitate A ,, it is possible to select preparations based on IgG with a higher titer of anti-blocking antibodies. allergens, making it possible to reduce allergic manifestations with greater efficiency.

The invention therefore aims to provide new preparations based on IgG having immunomodulatory anti-allergenic properties.

It also aims to provide a method allowing both to select such preparations from plasma.

It further relates to the applications of these preparations for the treatment of allergic manifestations by passive immunotherapy.

The preparations based on IgG according to the invention are characterized in that they have a titer in IgG of subclass 4, or IgG 4, of at least en¬ about 4% and in anti-allergenic blocking antibodies, in particular anti-pollen and anti-mite at least about 20 u / ml of preparation approximately, generally at least about 15 u / ml. According to another aspect, the IgG preparations of the invention have, in addition to an IgG 4 titer of at least about 4 **, a level of polymer chains of at least about 10%.

The term “polymer” is understood to mean in the following a chain of IgG monomer units, whatever their mode of interaction.

According to yet another aspect, the IgG-based preparations of the invention have, in addition to their titer in IgG 4 of at least about 4%, and their level in polymer chains of at least about 10% , anti-allergenic blocking antibody titers, in particular anti-pollen and anti-mite approximately 20 u / ml of preparation, generally at least approximately 15 u / ml.

The above preparations, according to a disposition of the invention contain on average 80 to 90%, in particular approximately 85% of IgG, 7 to 15%, in particular 10% in approximately IgA, and 3 to 8., especially around 5% of Ig.

In the following description, the expression "preparations of IgG ^H designates preparations based on IgG.

The invention also relates to a process for the fractionation of IgG preparations meeting the characteristics defined above.

In accordance with this process, the fractions of IgG obtained by alcoholic precipitation of human plasma are subjected to the action of a saturated linear fatty acid, preferably from C4 to C12, and the soluble part is recovered.

Human plasma can be noted that the following treatment beforehand: frozen plasma is gradually warmed to less than 5 ^* C. It présen¬ you as a solution containing a precipitate. The cryoprecipite contains an important part in particular Factor VIII, fibrinogen, fibronectin. The supernatant of cryoprecipite can be used in place of plasma for the preparation of precipitate A ,.

According to an advantageous arrangement, the solution collected is subjected to at least one purification step.

In a preferred embodiment of the invention, the IgG fractions used as starting material are of the type of those resulting from alcoholic fractionation of human plasma using 95% ethanol, in quantity sufficient for a final concentration of 19 to 22%, at pH 5.85, with gradual lowering of the temperature down to - 10 ^* C.

This type of alcoholic fractionation is described by Kistler and Nitschmann in the reference given above.

The addition of alcohol to the plasma leads to the formation of a precipitate A, which contains the fractions I + II + III.

Precipitate A is redissolved for the purposes of fractionation using saturated fatty acid.

Is advantageously used a buffer solution of pH 4, 5 to 5.5 preferably close to 4.8, at a tem¬ perature of between 15 and 30 ^° C, preferably 22 ^° C.

The saturated fatty acid is added at a rate of approximately 10 to 50 g / l, preferably 20 g / l to the tam¬ pon solution containing precipitate A, for a concentration of this solution in proteins of the order from 20 to 30 g / 1, preferably about 25 g / 1.

Advantageously, the fatty acid is added in the form of an emulsion to the buffer solution. The precipitate formed is collected, for example, by centrifugation, for the purposes of other industrial uses. The supernatant which contains the desired fractions is recovered.

A particularly preferred fatty acid, making it possible to protect IgG with great selectivity, consists of caprylic acid.

Given the therapeutic applications of the IgG preparations of the invention, the fatty acid solution obtained, more especially the caprylic solution, is advantageously subjected to at least one pu¬ rification step.

This is, in particular, to eliminate the fatty acid bound to proteins and the excess fatty acid.

In this regard, it is advantageous to use, according to a variant, an adjuvant endowed with an affinity for fatty acids, in particular, a salt such as tri-calcium phosphate. Previously, the pH is advantageously adjusted to about 6.5.

Concentrations of the order of 1 to 5 g / 1 of adjuvant, in particular of the order of 2 to 4, prove to be satisfactory for carrying out the desired separation.

The excess adjuvant is removed, for example, by centrifugation and the solution thus clarified is recovered and filtered, for example on activated carbon. according to another variant, the fatty acid solution is directly filtered, for example, on active char¬ without carrying out the step of adding tricalcium phosphate.

Other purification steps make it possible to perfect, if desired, the separation between the fatty acid and the IgG preparation of the invention.

Appropriate methods include alcoholic precipitation or a separation process based on the size difference between Ig and fatty acids such as dialysis, ultrafiltration or tangential ultrafiltration.

When alcoholic precipitation is carried out, the pH of the treated solution is advantageously adjusted to approximately 7.

Satisfactory conditions for alcoholic precipitation include the addition of alcohol, advantageously ethanol, to a final concentration of approximately 20 to 40%, in particular of the order of 30%, at a temperature below ambient, preferably on the solution cooled to about 0 ^° C, the temperature is lowered to -10 ^° C to -15 ^° C, especially -12 ^* C. during the addition of alcohol. The precipitate formed is collected. The clarified solution advantageously IgG mentioned above or the precipitate collected 1'issue of alcohol precipitation are avantageuse¬ ment processed to have preparations jecta- i ^ble -

This treatment includes an operation such as dialysis or ultrafiltration.

Good conditions for injecti <conditionsn intramuscularly are achieved with preparations containing about 100 g / l of protein. These concentrations are obtained for example by dialysis against NaCl because of 3 to 7 g / 1 of NaCl, preferably around 4.5 g / 1, at a temperature below ambient, advantageously about 4 ^* C. The osmolarity of the solution is adjusted to about 250 to 500 mOsM / l, in particular to about 300 mOsm / l, using, for example, a solubilizing and stabilizing agent such than the glycocolle.

Thanks to these provisions, it is possible to select, from the entire precipitate, the IgG preparations of great interest. The high titers of anti-allergenic blocking antibodies of the preparations of the invention and, according to another aspect, their high content of IgG polymer make them particularly suitable for the treatment of allergies. Their interest is further increased due

"Of their high tolerance.

The invention therefore also relates to the application of the preparations defined above, as active principles of medicaments.

Double-blind clinical experiments carried out with the preparations of the invention, injected into a sensitized patient, have shown the efficacy of these preparations in passive immunotherapy and in part have made it possible to significantly reduce the allergic manifestations observed in seasonal diseases.

The medicaments of the invention can be used for the treatment of allergic conditions, in particular seasonal pollinosis or seasonal or non allergic rhinitis due to pollen or house dust.

In subjects with hay fever, repeated injection at regular intervals can prevent or reduce the clinical manifestations of the allergy, whether nasal, ocular or respiratory.

These drugs constitute desensitization adjuvants which are particularly advantageous at the start of desensitization by reinforcing and supplementing desensitization, by allowing the amounts of allergens injected to progress more rapidly and by avoiding the use of corticosteroid therapy. This passive immunotherapy does not interfere with active immunotherapy (desensitization). The injection of anti-allergen IgG antibodies does not prevent the rise of IgG antibodies observed during desensitization. The drugs of the invention can therefore be used in conjunction with desensitization treatments, whether old or recent.

They can also be used in the event of failure of desensitization or late desensitization.

The advantage of the medicaments of the invention is more important during a resurgence of allergic manifestations after a viral disease having led to a temporary functional immuno-depression, of aperiodic spasmodic coryza and of rhino-tracheobron- allergic chites due in particular to house dust.

The medicaments of the invention are injectable intramuscularly.

They are advantageously presented in the form of syringes, self-injectable by the intramuscular route containing, for example, 5 or 10 ml of a 100 g solution per liter of IgG preparation according to the invention.

Preferred IgG preparations have the following characteristics:

These are sterile, nonpyrogenic, non-toxic preparations of pH 6, 4 to 7.2 approximately, advantageously containing around 100 to 170 g / l of total protein. Their antibody activity is greater than 15 u / ml as anti-pollen and greater than 15 u / ml as anti-mites. The electrophoretic purity of these preparations is greater than approximately 90% and the osmolarity is of the order of 250 to 500 mOsm / l.

These solutions advantageously contain an antiseptic, preservative agent such as sodium ercurothiolate. Doses less than or equal to 1 for About 10,000 of this agent is found to be suitable. They also contain a solubilising and stabilizing agent such as glycocolle. Appropriate glycocolle concentrations are of the order of 18 to 25 g / l. The sodium and chloride contents> are approximately

7 g / 1.

By way of example, the dosages which can be used are given below in the case of: a) moderate allergic manifestations, and b) slight immunodeficiencies of immunomodulation disorders or allergic manifestations severe: a)

-weight of the patient less than 60 kg: 2 injections of 5 ml per week for three weeks,

-weight of the patient greater than 60 kg: 2 injections of 10 ml per week for three weeks. b)

-weight of the patient less than 60 kg: 3 to 4 injections of 5ml per week for three weeks,

-weight of the patient greater than 60 kg: 3 to 4 injections of 10 ml per week for three weeks.

The attending physician will reserve the right, if the case arises, to modify the above dosage, in accordance with specific cases.

Example n'1: process for obtaining a fraction of IσG according to the invention

1) Preparation of the starting material by alcoholic fractionation from the plasma.

Were thawed in a controlled manner the pro¬ plasma from pockets or flasks poolages, or stored po¬ individual tasks at -40 ^° C.

It is gradually warmed by passing through a cold room to -10 "C and 0 ^* C and then thawed in a water bath at +3 ^* C, so that the final temperature remains below +3 ^* C. After verification of the protein level, of the pH and bacteriological examination, and elimination of the cryoprecipitate, an ethanol fractionation is carried out according to the Nitschmann-Kistler method which is discussed above.

It will be recalled that the main stages of this alcoholic fractionation include: adjusting the protein level to 50 g / l using a sodium chloride solution at 0.5 g%, precipitation of the immunoglobulins at pH 5 85 = 1'éthanol by 95% in sufficient quantity for a final concentration of 19% (or 22%) by gradually lowering the temperature to -10 ^° C,

- centrifugation and recovery of the precipitate constituting the immunoglobulins (precipitate A), and, where appropriate,

- freezing at -25 ^* C.

The precipitate A. which contains the fractions I + II + III is in the form of a paste. 2) Caprylic fractionation a) re-solution

The precipitate is redissolved in an acetic buffer / acetate mixture of pH 4.8-4.9 obtained by mixing a 0.05 M solution of acetic acid and a 0.05 M solution of sodium acetate.

9 l of buffer are used per kg of dough. It serves ob¬ progressive dilaceration of the pulp in the buffer at a temperature of 20 to 22 ^° C.

The mixture is left for about 2 hours at rest, for the purpose of homogenization.

The protein level is around 25 g / l. b) caprylic precipitation α: addition of caprylic acid.

20 g / l of caprylic acid (99% purity - ref. 193- erck) are added, with stirring. After the end of the introduction, the stirring is continued for another 45 minutes.

According to an alternative embodiment, an emulsion containing 20 g / l of caprylic acid (99% purity - ref. 193-Merck) is added, with stirring, to the protein solution. Stirring is continued until the appearance of a protein precipitate, the duration of this operation being in this case reduced. β: centrifugation.

Without allowing the suspension to cool, it is centrifuged with a flow rate of approximately 50 l / h (device: Sharples AS 16). The precipitate obtained (approximately 30 kg for 40 kg), containing glycoproteins and albumin, can be collected and reused for other industrial applications, for example as a source of albumen. The supernatant is collected (approximately 360 to 380 l). γ: pH adjustment.

The pH of the supernatant is adjusted to 6.5 using 1N NaOH. δ: addition of tricalcium phosphate.

Tricalcium phosphate is added in an amount of 2 g / l of supernatant and the mixture is stirred for 30 minutes. ε: centrifugation.

The phosphate is removed by centrifugation carried out under the above conditions. η: filtration.

The supernatant is filtered on plates containing activated carbon (for example plates of Seitz AKS4). The operation lasts approximately 1 hour. ζ: pH adjustment.

The pH is adjusted to 7 with NaOH. λ: precipitation of IgG with 1% ethanol at 30%.

Ethanol qs 30% is added to the solution precooled to 0 ^# C. During the addition of alcohol, we - lower the temperature to -12 ^* C. According to an alternative embodiment of the method according to the invention, this precipitation can be replaced by an ultrafiltration as described below in step ι. θ: centrifugation.

The solution is first centrifuged with a flow rate of 30 l / h (a Sharples AS 16 device is used).

Is collected for 40 kg of precipitate &, about 12 kg of precipitate, bluish, which has a viscous appearance.

K: re-solution.

The precipitate is redissolved at a rate of 5 l / kg in 60 l of NaCl buffer: 8 g / 1, glycine: 4.5 g / 1 (in the case of dialysis) or 11 g / 1 (in the case of l 'ultra¬ filtration).

The pH is adjusted to 7.5 if necessary. The protein level is around 50 g / l. ι -. dialysis or ultra iltration.

The solution, previously filtered, is dialyzed against NaCl (4.5 g / 1) at + 4 "C for approximately 10 hours. The protein level (approximately 140 g / 1) is checked.

The osmolarity of the solution is adjusted to approximately 300 mOsm / 1 using glycine (11 g / 1). Sodium merthiolate (1 p 10 000) is added, then filtered sté¬ rilly on a filter with pore diameters of 0.22 μ.

Prior to distribution in a syringe, the protein level is adjusted to a minimum of 100 g / l (in practice 105 to 100 g / l). The doses of salts, glycocolle and merthiolate are supplemented according to dilution, then they are filtered sterile. These preparations are preferably stored at a temperature of the order of +2 to +6 ^* C.

According to an alternative embodiment of the method according to the invention, the product obtained in step γ described above is directly filtered on plates containing activated carbon, according to the method described in step η above, without going through steps ζ and ε above, in particular when the supernatant is not present in a milky or opalescent form.

Evaluation of the IgG, I A, IσM and IαG 4 subclass of IgG levels:

One operates according to the technique described by ancini and col in Immuno Che istry, n ^* 3, p.235, 1965. One uses a specific commercial antiserum (of Nordic brand or Dutch Red Cross for example), and witnesses of known IgG or IgA or IgM level. The control for IgG 4 is constituted by a pool of 50 healthy blood donors whose IgG 4 level is 0.4 g / 1.

The results show that the IgG preparations according to the invention contain on average 85% of IgG, 10% of IgA and 5% of IgM. Their IgG 4 level is greater than or equal to 4

The comparison of six batches of preparation according to the invention and six batches of gamma globulin fractionated by alcohol gives an average level of 4.5% of IgG 4 for the first and of 2% for the second. The control plasma pool contained 3% IgG 4.

Determination of the activity of anti-allergenic antibodies of the IgG type (blocking antibodies): a) dosing principle:

1- Anti-allergenic antibodies are measured by a radioimmunological test in solid phase. Nitro-cellulose disks on which the allergen extracts have been covalently coupled are incubated with dilutions of seru s or immunoglobulins. After several washes, the discs are incubated with the staphylococcal protein labeled with iodine 125 (Department of Radioisotopes. CNTS). Protein A binds with a high affinity to the Fc part of 93% of human IgG. After 18 h of contacts, the unbound protein A is eluted by a series of washes.

The amount of protein A linked to IgG is measured by a gamma radiation counter and expressed in% relative to the total amount of radioactivity introduced into the reaction.

2- According to another method, of the Elisa type (Enzyme linked immuno-sorbent assay), the allergens extracted from grass pollen are absorbed on microtiter plates and then brought into contact with solutions of the invention. The presence of IgG fixed by allergens is revealed by an immunoglobulin labeled with alkaline phosphatase or peroxidase. Sigmoidal curves are obtained by expressing the optical density as a function of the dilution of the solutions.

These curves allow the dosage of anti-allergenic IgGs in the therapeutic preparation of Immunoglobulins. B) calculation of the number of units present in the solutions of the invention:

The activity of a serum pool of 100 donors (2 ml of each serum) serves as a reference and contains by definition 1 unit / ml. It is measured with dilutions of serum between 1/200 and 1/25. A reference curve is established between the dilution of the serum pool and the percentage of binding of protein A-

The therapeutic gamma globulin solutions are diluted so as to obtain a percentage of protein fixation corresponding to dilutions of approximately 1/100 of the pool of sera.

The previously established reference curve then makes it possible to calculate the number of units / ml of anti-allergen immunoglobulins present in the therapeutic solution. c) standards: IgG antibodies are assayed for their activity vis-à-vis at least one extract of grass pollen (phleum pratense, or Dactylis glomerata) and an extract of mites (Der atophagoids pteronyssinus).

The anti-allergenic blocking antibody titer of the IgG preparations according to the invention is at least 15 u / ml anti-pollen and 15 u / ml anti-mites. The average of the anti-pollen activity of 16 batches of preparation according to the invention is 23 u / ml, the level of anti-mites being identical or slightly higher Rate of polymers Permeation chromatography is carried out with a gel separating PM proteins between 20,000 and 350,000 daltons.

The following results were obtained by operating as follows:

A column of 100 cm, diameter 2.5 _Q cm, containing the product sold under the brand sousltrogel, is used. AcA 34 (LKB). 100 g of proteins are deposited in 2.5 ml.

The elution rate is 20 ml / h. The peaks are detected at 280 mm (measurement of the optical density ^" ). The surface is evaluated by plani etry. The results obtained show that the polymer levels of the IgG preparations of the invention are greater than 10% (average of 5 batches 15%) while the fractions of immunoglobulins fractionated by alcohol _Q rarely exceed 5% (average of 13 batches 4.5%).

The study of the composition of the monomer, dimer and polymer fractions of the preparations of the invention showed a variation in composition in i munoglobulin of each of the fractions. 5 The table below shows the different IgG, IgA and IgM levels measured respectively. Preparation of "dimer""monomer" fraction 1 * polymerized invention

IgG 85% 50% 70 95% IgA 10% 10% * 25 5% IgM 5% 40 S 5 0%

Example ^No. 2: results of testing cli¬ lunches made with solutions prepared according 1'invention.

100 g / l solutions of IgG preparations according to the invention are used, titrating 15 units / ml anti-pollen, 15 units / ml anti-mites and containing as additive 1 p 10,000 of mercurothiolate .

According to the therapeutic protocol used, a series of intramuscular injections of preparation according to the invention was carried out, at a rate of 20 ml / week, for 5 weeks. The preparation has been used in allergic subjects, without prejudging the original link of the allergy with pollens or mites. Activity was assessed by daily observation of the symptoms of the disease. Clinical manifestations (nasal, ocular and respiratory) were noted. Out of 33 patients subjected to this treatment, 15 very good results were obtained, 10 good results, 8 failures were observed.

In another experiment, on 19 subjects, 8 very good results, 3 good results and 8 failures were obtained.

The placebo group differs from the group of patients treated with the preparation according to the invention by a statistically lower "symptom score" during the last three weeks of treatment and by significantly lower drug consumption. The various tests carried out have shown that the tolerance of the IgG preparations according to the invention is always satisfactory and that an improvement in the clinical signs of the disease has been observed.

The positive results recorded show a regulatory action on the immune response of these subjects.

The use of the preparations according to the invention, as defined above, for an immunomodulatory activity, also comes within the scope of the invention.

These immunomodulation phenomena play in particular an important role in the case of certain immune deficits, in particular those encountered in infants, and in autoimmune pathology.

Claims

1. IgG preparations, characterized in that they have a titer in IgG of subclass 4, or IgG 4 of at least about 4% and titers in anti-allergenic blocking antibodies, in particular anti-pollen and anti-mite of at least about 20 u / ml of preparation approximately, generally of at least about 15 u / ml.

2. IgG-based preparations, characterized in that they have an IgG 4 titer of at least about 4% and a level of polymer chains of at least about 10%.

3. Preparations based on IgG, characterized in that they have an IgG 4 titer of at least about 4 \, a level of polymer chains of at least about 10% and titers of blocking antibodies an¬ ti -allergens, in particular anti-pollen and anti-mites of about 20 u / ml of preparation, generally at least about 15 u / ml.

4. Preparations according to any one of claims 1 to 3, characterized in that they contain on average 80 to 90%, in particular approximately 85% of IgG, 7 to 15, in particular approximately 10% of 'IgA, and 3 to 8, including about 5% of IgM.

5. IgG-based preparations any one of claims 1 to 4, characterized in that it consists of sterile, non-pyrogenic, non-toxic preparations of pH 6.4 to 7.2 approximately, advantageously containing of the order of 100 to 170 g / l of total protein, having an antibody activity greater than 15 u / ml as anti-pollen and greater than 15 u / ml as anti-mites, a electrophoretic purity greater than about 90% and an osmolarity of the order of 250 to 500 mOsm / l, these preparations advantageously containing an antiseptic agent, a preservative, such as sodium mercurothiolate, in particular, at doses less than or equal to 1 per 10,000, as well as a solubilizing and stabilization such as glycol adhesive, in particular at a rate of approximately 18 to 25 g / l.

6. Method for obtaining preparations of IgG of subclass 4 characterized in that the immunoglobulin frac¬ tions obtained by alcoholic precipitation of treated or untreated human plasma are subjected to the action of a saturated linear fatty acid, preferably from C4 to C12, and in that the soluble part is advantageously subjected to at least one purification step.

7. Method according to claim 6, characterized in that the IgG fractions used as material. start are of the type of those resulting from alcoholic fractionation of human plasma treated or untreated with 95% ethanol, in sufficient quantity for a final concentration of 19 to 22%, at pH 5.85, with a- gradual Lowering temperature to -10 ^° C, the addition of alcohol leading to the formation of a pré¬ cipité a containing the IgG.

8. Method according to claim 6 or 7, charac¬ terized in that the precipitate A _r dissolved, in particular in a buffer solution of pH 4.5 to 5.5, preferably close to 4.8, is treated by adding a saturated fatty acid, in part by about 10 to 50%, preferably about 20 g / 1 of buffer solution containing precipitate A, for a concentration of this solution in proteins of the order of 20 to 30 g / 1, preferably

25 g / 1.

9. Method according to any one of claims 6 to 8, characterized in that caprylic acid is used as saturated fatty acid.

10. A method according to any one of reven¬ dications 6 to 9, characterized in that it further comprises at least one purification step such as the addition of an adjuvant with an affinity for acids fatty, in particular of a salt, such as tricalcium phosphate, preferably at a rate of 1 to 5 g / 1, in particular from 2 to 4 g / 1 and / or an alcoholic precipitation step and / or a separation based on the size difference between the Ig and the fatty acids such as dialysis or ultrafiltration.

11. Process according to claim 10, characterized in that the alcoholic precipitation step is carried out by addition of alcohol, advantageously ethaol to a final concentration of approximately 20 to

40%, in particular, of the order of 30%, at a temperature below ambient, preferably on the solution cooled to around 0 ° C. whose temperature is lowered to -10 ° C. at - 15 "C, in particular -12 ° C. approximately during the addition of alcohol, and in that the dialysis is carried out against NaCl at a rate of 3 to 7 g / 1 of NaCl, preferably approximately 4, 5 g / 1 at a temperature higher infé¬ ^ ambient, preferably about 4 ^° C and in that one adds the osmolarity of the solution to about 250 to 500 mOsm / 1 in particular to about 300 m0sm / l, using, for example, a solubilizing and stabilizing agent such as glycocolle.

12. Medicines characterized in that they contain in their active principle at least one preparation of IgG according to any one of claims 1 to 5.

13. Medicines according to claim 12, ca¬ characterized in that they are in the form of sterile solutions injectable intramuscularly.