JP2005160355A - New genotype determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple detection method for solving the problem of hybridization stage in a gene detection method using a bead and a reagent. <P>SOLUTION: In the gene detection method using a hybridization method by which the surface of a bead has a solid-phase surface, in the stage of hybridization between a probe gene in a solid phase on the surface of a bead and an amplification product obtained by gene amplification from a gene specimen, the denaturation of the gene amplification product to a single strand is carried out by heating to remarkably simplify a technique. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for detecting a gene. More specifically, the present invention relates to a gene detection method using a hybridization method using beads as a solid phase surface, which is simplified by performing denaturation by heating.

  Gene detection methods using the hybridization method using the bead surface as a solid phase have existed for some time, but in the Luminex method, the polystyrene beads used are colored with a fluorescent substance, and the color tone and concentration of the fluorescent substance (the amount of fluorescence) ) Is a technology that can be distinguished into 100 types. The normal bead method could only detect one type of bead per tube, that is, one type of probe, but the Luminex method can detect up to 100 types of probes with a single tube. It is possible to obtain twice the processing capacity and information amount.

Several gene detection techniques using the Luminex method exist, but an alkaline solution has been used to denature gene amplification products and the like into single strands at the hybridization stage.
A sodium hydroxide solution or the like is used as the alkaline solution, but it is a deleterious substance and needs to be handled with care. After denaturation, neutralization using an acidic solution is necessary, which is very complicated by hand. In addition, there are many stages in which a solution is added to gene amplification products and the like, and a decrease in inspection accuracy due to contamination can be considered.
Fulton RJ, McDade RL, Smith PL et al Clin. Chem. 43: 1749-1756 1997 .: Advanced multiplexed analysis with the Flow Metrix system. Sakauchi Makoto, Hirose Koichi, Ishikawa Yoshihide et al .: Journal of the Japan Society for Histological Compatibility, 8: 175-186 2002: HLA-A, B, DR SSOP typing method for Japanese population Nakajima Fumiaki, Nakamura Atsuko, Yokota Toshikazu: Japanese 4-digit HLA haplotype distribution, Journal of the Japanese Society for Histological Compatibility, 8: 1-32, 2001. Tatsuya Akaza: A Consideration of Japanese HLA-HLA Frequency: Journal of the Japanese Society for Histological Compatibility, 5: 18-22, 1998. Eri Yoshikawa, Noriko Miyahara, Taeko Naruse, Kazunori Shimada, Fumihiro Higashi, Keitaka Hara, Hidetoshi Sasako: Journal of the Japanese Society for Histological Compatibility, 10: 21-31 2003: HLA-A, using PCR-Luminex method Examination of Japanese 4-digit DNA typing method for HLA-B and HLA-DRB1 genes http://www.ebi.ac.uk/imgt/hla/docs/rel notes.html http://www.aseatta.org.au/nomencla.htm http://square.umin.ac.jp/JSHI/hla_data/data.html http://www.ebi.ac.uk/imgt/hla/download.html http://www.ncbi.nlm.nih.gov/Web/Search/ http://www.ddbj.nig.ac.jp/

Therefore, the object of the present invention is to solve the problems in the prior art at the stage of denaturing a gene to be detected into a single strand in a gene detection technique using a hybridization method using beads. It is to provide a method and kit that are few, simple, and high in inspection accuracy.

The present inventors have found that the above-mentioned problem can be solved by performing denaturation of a gene to be detected into a single strand by heating when the beads on which the probe is solid-phased have heat resistance.
According to the present invention, there are provided a gene detection method and a kit in which the danger of the solution, the complexity of the procedure, the problem of contamination and the like are solved with respect to the gene detection method by the hybridization method using beads.

  According to the present invention, it is possible to simplify the method of the hybridization reaction stage in the gene detection technique using beads. Furthermore, it is effective for avoiding the danger of the solution to be used and for reducing the determination accuracy due to contamination. HLA genotyping methods and kits employing this method are very useful for HLA typing, which is important for bone marrow transplantation, organ transplantation, and blood transfusion treatment.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides a gene detection method in which, when hybridizing an oligonucleotide probe solid-phased on a bead surface and a gene amplification product, the probe solid-phase beads and the gene amplification product are mixed, and hybridization is performed after heat denaturation by heating. provide.
In a preferred embodiment, the present invention uses a probe solid phase bead in which an oligo probe for detection is immobilized on the surface of a polystyrene fluorescent bead and an amplification product obtained by performing gene amplification using a gene sample as a template, and a gene is obtained by a hybridization method. In the detection method (Luminex method) developed by Luminex, which detects mutations, after mixing the probe solid phase beads and the amplification product, the denaturation of the amplification product into a single strand is thermally denatured by heating. And a genotyping method characterized by performing thermal denaturation and hybridization successively by lowering to an optimal hybridization temperature after denaturation.

In a preferred embodiment, the heat denaturation condition by heating is 1 to 5 minutes at 90 ° C. or higher. In the most preferred embodiment, the heat denaturing conditions are 95 ° C. for 2 minutes.
In a preferred embodiment, the hybridization conditions after heat denaturation are at 30 ° C. to 70 ° C. for 15 to 90 minutes. In the most preferred embodiment, the hybridization conditions after heat denaturation are at 52 ° C. for 60 minutes.

According to the genotyping method of the present invention, genotypes in the WHO (World Health Organization) notation method, the first and second digits (judgment of serological level), the third digit and the fourth digit (gene mutation) And genotypes with amino acid mutations) and 5th and 6th digits (determination of genotypes that have genotype mutations but no amino acid mutations) alleles in a shorter time than before It becomes possible to judge.
The most suitable for the genotyping method of the present invention is the determination of the allelic type of human leukocyte antigen (HLA), which is a human major histocompatibility antigen. Kits using various methods such as PCR-SSO (Sequence Specific Oligonucleatide), PCR-SSP (Sequence Specific Primer), and SBT (Sequence Based Typing) are commercially available. However, many of the conventional kits from overseas manufacturers do not correspond to the Japanese genotype, so there is no problem with the 2-digit level judgment, but at the 4-digit level, the genotype exists in the Japanese and cannot be identified. There are cases. In addition, kits that can determine four digits have the problem of ambiguity with rare genotypes.

The gene for HLA is located on human chromosome 6. HLA class I HLA-A and HLA-B,
HLA class II HLA-DRB1 is very important information for bone marrow transplantation, organ transplantation and blood transfusion treatment. Furthermore, it has been suggested that there is a difference in HLA type and disease resistance and resistance to external enemies such as viruses. As for these three antigen genes, new genotypes continue to be discovered one after another, and all of them already exceed 100, and exceeding 1000 is a matter of time.
For example, HLA class I HLA-A has about 200 genotypes registered, and EMBL
(Http://www.ebi.ac.uk/imgt/hla/docs/rel notes.html (Non-patent document 6)), ASEATTA (The Australasian and South East Asian, Tissue Typing Assoc. Ic.) (http://www.aseatta.org.au/nomencla.htm (Non-patent document 7)) And JSHI (Japan Society for Histocompatibility) (see data such as http://square.umin.ac.jp/JSHI/hla_data/data.html (Non-Patent Document 8)). In order to determine the genotype, it is determined by the gene mutation present in the exon 2 region and the exon 3 region. In this method, the genotype is determined by detecting these gene mutations using a probe.

  The target of determination is a genomic gene, m-RNA, or the like, but since it is difficult to quantitatively determine the gene itself, gene amplification is performed. In this method, the PCR method (polymerase chain reaction) is used, but other amplification methods can also be used.

  Primers that amplify the exon 2 region of HLA-A are set in intron 1 and intron 2, and primers that amplify exon 3 are set in intron 2 and intron 3. Synthetic oligos are used for these primers, but biotin is modified at the synthesis stage, whereby biotin is labeled on the amplification product. The label to be modified is not limited to biotin, and DNP (dinitrophenyl), DIG (digoxigenin), and the like can also be used.

  The synthesized primers for amplifying the exon 2 region and the exon 3 region of HLA-A are mixed at an appropriate concentration ratio to prepare a master mix solution containing dNTPs, Taq DNA polymerase, and a buffer for Taq DNA polymerase.

  Add 50-100 ng of the extracted genomic gene as a template to the master mix solution, make the volume 25 μL, and set in the thermal cycler. The temperature time condition is 93 ° C, 30 seconds → 65 ° C, 30 seconds → 72 ° C, 30 seconds is repeated 40 times to amplify the exon 2 region and exon 3 region of the target HLA-A gene, To do.

  In order to determine the genotype of HLA-A, it is necessary to set 41 types of probes. These probes are designed so that the presence or absence of one to several gene mutations contained in the sequence can be discriminated. One of each of these 41 types of probes is immobilized on 41 types of fluorescent beads. A synthetic oligo is used as the probe, and the amino group is modified at the synthesis stage. A fluorescent bead having a carboxyl group bound to the surface is used, and an oligo probe modified with an amino group is solid-phased using EDC (ethyldimethylaminopropylcarbodiimide).

  The prepared probe solid phase fluorescent beads are re-dispersed in a hybridization buffer containing TMAC (tetramethylammonium chloride), EDTA (ethylenediaminetetraacetic acid), sarcosine and Tris buffer to obtain a bead mix solution.

  Add the gene amplification product to an appropriate amount of bead mix solution, set it in the thermal cycler, and set the temperature conditions to 95 ° C, 2 minutes → 52 ° C, 60 minutes. At this stage, thermal denaturation of the gene amplification product at 95 ° C. and hybridization reaction at 52 ° C. are successively performed.

  When the gene sequence of the gene amplification product matches the sequence of the probe immobilized on the beads by the hybridization reaction, the probe and the gene amplification product hybridize, and as a result, biotin is labeled on the beads.

After the hybridization reaction, SA-PE (streptavidin-labeled phycoerythrin) is added, and biotin and SA are bound to label PE.
The beads are detected by a dedicated detection device. The detection device applies two colors of laser to the beads, while measuring the color and concentration of the fluorescent dye on the beads itself to identify the beads, and on the other hand, the presence or absence of PE labeled by the reaction and the fluorescence intensity. taking measurement. This detector adopts the flowmetry principle, and can identify beads and measure the fluorescence intensity of PE at a speed of approximately 500 per second.

  From the fluorescence intensity data obtained by the detection device, positive / negative of each probe solid-phased on each bead is determined. From the determination result, the HLA genotype is determined using a dedicated determination pattern table or dedicated determination software.

  About 400 types of HLA-B genotypes are registered according to combinations of gene mutations scattered in the exon 2 region and the exon 3 region of the HLA-B gene (see Non-Patent Documents 6 to 8). The genotype of HLA-B is the same as described above, except that the exon 2 and exon 3 regions are amplified, the primers for gene amplification are dedicated to HLA-B, and the probes are 51 types dedicated to HLA-B. Judgment is possible by the same method as HLA-A.

  The genotypes of HLA-DRB1 are classified into about 300 types depending on the combination of genetic mutations scattered in the exon 2 region of the HLA-DRB1 gene (see Non-Patent Documents 6 to 8). As for the genotype of HLA-DRB1, the gene amplification region is only exon 2, and two amplifications are necessary for one specimen. The probe requires 48 types dedicated to HLA-DRB1, but other methods can be determined by the same method.

  Although new alleles continue to be discovered for HLA, the present invention can perform type determination by associating the set number and set location of primers and probes with them. The preferred length of the primer and probe for efficient determination is 15 to 30 bases, more preferably 16 to 28 bases for the primer, and 16 to 26 bases for the probe. For HLA, for example, primers and probes can be set based on the EMBL sequence database (http://www.ebi.ac.uk/imgt/hla/download.html (Non-patent Document 9)). . Alternatively, Japan Society for Histological Compatibility (http://square.umin.ac.jp/JSHI/hla_data/data.html (Non-Patent Document 8)), GenBank (http://www.ncbi.nlm.nih.gov Sequence databases such as / Web / Search / (Non-Patent Document 10)) and DDBJ (http://www.ddbj.nig.ac.jp/ (Non-Patent Document 11)) can also be used.

Furthermore, according to this invention, the kit used for the said genotyping method is also provided.
In a preferred embodiment, the kit includes primers, probes, dNTPs, Taq DNA polymerase, and a buffer.

Materials and methods
1. Specimen and DNA Extraction Genomic DNA was extracted and purified from 138 specimens of cultured cells established using EB virus from Japanese healthy individuals or B cells derived from them using QIAGEN kits. DNA was quantified and purity was measured by measuring absorbance at 260 nm and 280 nm, and the concentration was adjusted to 10-20 ng / μl. The HLA genotypes of these specimens are known by determination by another method such as the SBT method.
2. PCR
For the HLA-A and HLA-B genes, exon 2 and exon 3 were amplified by the PCR method, respectively. 5'-primers for exon 2 amplification are 3 types for HLA-A and -B in intron 1 region, 3'-primer is 1 type for both HLA-A and -B in intron 2 region, 5 'for exon 3 amplification -3 types of primers for HLA-A, 2 types of HLA-B for intron 2 region, 3'-primer for HLA-A and -B, 2 types for intron 3 region, both exon 2 and exon 3 Primers were mixed and HLA-A and HLA-B were PCR amplified in 1 tube each (Table 1). For HLA-DRB1, exon 2 was amplified with two types of primer sets, PS1 and PS2. For PS1, 5'-primer is set in intron 1 region and 3'-primer is set in exon 2 region.PS2 is set in exon 2 region for all 4 types of F primer and 1 type of R primer. PCR amplification was performed in one tube (Table 1). The primer used was modified with biotin on the 5 ′ side. The size of the amplified product is 466 bp for exon 2 of the HLA-A gene, 318 bp for exon 3, 448 bp for exon 2 of HLA-B, 359 bp for exon 3, 280 bp for PS1 for HLA-DRB1, and 265 for PS2. -271 bp. The amplification buffer was a final concentration of 50 mM KCl, 10 mM Tris-HCl pH 8.3, 1.5 mM MgCl ₂ , 2% DMSO, 0.2 mM dNTPs. To this was added 0.5-1.0 μM of the above primer set, 50 U / ml Taq DNA polymerase and 50-100 ng of sample genomic DNA to make a total volume of 25 μL. 4 types of prepared gene amplification solutions (HLA-A, B, DRB1-PS1 and DRB1-PS2) are set in GeneAmp 9700 (Applied biosystems), 93 ° C, 30 seconds → 65 ° C, 30 seconds → 72 ° C, PCR amplification was performed in 40 seconds for 30 seconds. As for GeneAmp9700, the gold block type and aluminum type can be used. Regarding GeneAmp9600, it was necessary to optimize the conditions by changing the denaturation temperature.

3. Luminex method (Figure 2)
33 types of HLA-A gene, 46 types of B, 24 types of DRB1-PS1 for the purpose of discriminating typing of alleles (2-4) whose gene frequency is 0.1% or more in the Japanese population 20 types of probes were designed using DRB1-PS2 (Table 2). Among these, probes for confirming amplification products (positive control probes) designed for exons 2 and 3 for HLA-A and B and PS1 and PS2 for HLA-DRB1 are included. The above-mentioned sequence-specific oligo probe was synthesized by modifying the amino group at the end, and immobilized on Luminex fluorescent beads by the method recommended by Luminex. These beads were mixed at 100 beads / μL to prepare bead mixes for HLA-A, -B, DRB1-PS1 and DRB1-PS2, respectively. Add hybridization reaction buffer (3.75 M TMAC, 62.5 mM TB pH8.0, 0.5 mM EDTA, 0.125% N-lauroyl sarcosine) to 40 μL, add 5 μL of the above bead mix and 5 μL of PCR amplification product to 50 μL. . Since the bead mix and PCR amplification product are set in HLA-A, B, DRB1-PS1, and DRB1-PS2, 4 tubes are required for simultaneous ABDR determination. These were set in GeneAmp 9700, and denaturation and hybridization were performed at 95 ° C., 2 minutes → 52 ° C., 60 minutes. After hybridization, the mixture was centrifuged at 150 × g for 15 minutes using a swing-type plate centrifuge, and the supernatant was removed. Next, streptavidin-labeled phycoerythrin (SA-PE, Sigma) was diluted 100-fold with PBS-tween (1 × PBS pH 7.5, 0.01% Tween-20), and 35 μL was added. After stirring by pipetting, HLA-A and B were mixed together in 1 well to make 70 μL, and similarly DRB1-PS1 and DRB1-PS2 were mixed in 1 well to make 70 μL. They were set in GeneAmp 9700, reacted at 52 ° C. for 5 minutes, then set in the Luminex 100 system (for 96 samples) and measured. The type determination was performed using the determination software that input the obtained reaction pattern. This judgment software has been developed to handle all types of Japanese HLA genes with a frequency of 0.1% or higher, and to display all combinations that cannot be identified.

Results PCR amplification was performed on 138 samples of genomic DNA derived from Japanese, and HLA-A, HLA-B and HLA-DRB1 genotyping was performed according to the Luminex method according to the materials and methods. In the case of the Luminex method, since the negative control must always be measured to detect the autofluorescence value of the beads and to confirm the contamination, the maximum number that can be measured simultaneously was 95 samples. In this study, 48 samples, which are half the maximum number of tests, were set as one set, and 47 samples excluding negative controls were tested 3 times. At the stage of detection using the Luminex device, 79 beads of HLA-A and B and 44 beads of PS1 and PS2 mixed in HLA-DRB1 were measured simultaneously. Table 3-5 shows probe determination patterns of HLA-A, HLA-B, and HLA-DRB1 gene typing, respectively. With this method, alleles (alleles) (see Table 3-5), which have a gene frequency of 0.1% or more in the Japanese population, can be typed at the 4-digit level for homo and hetero combinations. In addition, A29 and A32, which are frequently observed in other populations other than Japanese, are also a type-determinable method, but the 138 specimens used this time do not contain A29 or A32 (from whites) We have confirmed that type determination can be performed on specimens).

  As a result of judging positive and negative with the detected fluorescence intensity and the cut-off value set for each bead and using genotyping software, one sample with HLA-A and one sample with HLA-B Except for this, it was consistent with the known HLA type at a 4-digit level. Therefore, the determination achievement rate and accuracy were 99.3% for the HLA-A gene, 99.3% for the HLA-B gene, and 100% for the HLA-DRB1 gene. Table 6 shows representative examples of HLA-A, HLA-B and HLA-DRB1 genotyping. The two specimens that could not be judged cannot be judged even after retesting, and the fluorescence value of the positive beads is low. Therefore, because of the multiplex PCR, poor gene amplification due to unknown components brought in from the DNA sample It was thought that this could be the cause. In addition, as shown in FIG. 3, in the determination of the fluorescence intensity and cut-off value of the oligo probe-bound bead B17 used for HLA-B typing, the fluorescence value of the poorly amplified positive sample and the nonspecificity of the excessively amplified negative sample are non-specific. Fluorescence values may be almost the same, and these samples were confirmed by retesting.

As a result of the above, except for the unambiguous combination of [A * 2402, 2601] and [A * 2404, 2605], it was possible to type the assumed Japanese 4-digit genotype. This method makes it impossible to distinguish genotypes that have not yet been confirmed in Japanese, for example, [A * 3201, 7401] for HLA-A [A * 3201,-] specimens. Etc. (Table 3), the presence of several combinations of genotypes that were indistinguishable (ambiguity) was confirmed. The alleles that have been confirmed to exist in Japanese were only combinations of [A * 2402, 2601] and [A * 2404, 2605] as described above. Therefore, the Luminex method developed in this paper, except for the combination of [A * 2402, 2601] and [A * 2404, 2605], is the Japanese allele of the HLA-A, HLA-B and HLA-DRB1 genes. It became clear that any combination is highly accurate typing that can be identified at the 4-digit level.
Consideration
Gene frequency in Japanese by Luminex method using fluorescent beads on which 33 probes for HLA-A, 46 probes for HLA-B, 24 probes for HLA-DRB1-PS1, and 20 probes for HLA-DRB1-PS2 are immobilized. [A * 2402, 2601] and [A * 2404, 2605] for alleles in which 0.1% or more occur, ie, 33 types of HLA-A gene, 55 types of HLA-B, and 34 types of HLA-DRB1 Except for combinations that are ambiguity, it was possible to discriminate 4-digit typing including heterogeneous combinations (Table 3-5). There was only one combination of [A * 2402, 2601] and [A * 2404, 2605] that resulted in ambiguity in this study. As for this [A * 2402, 2601] and [A * 2404, 2605] combination that is indistinguishable (ambiguity), both A * 2404 and 2605 are rare alleles in Japan, but they cannot be distinguished (ambiguity). A * 2402 and 2601 are 8 samples out of 138 samples, so a new probe is considered necessary. Therefore, a new probe for discriminating between A * 2402 and A * 2404 will be added, and HLA-A will have a total of 34 probes to solve this ambiguity problem.

  A low fluorescence value was observed in one specimen with HLA-A and one specimen with HLA-B, which was thought to be due to poor PCR amplification due to unknown components brought in from the DNA sample. In other words, because it is a multiplex PCR that includes multiple primers, amplification efficiency depends on the purity and heterogeneous combination of DNA, and because of the presence of homologous genes on the genome, the composition of genomic DNA solution is brought An unknown component may affect PCR amplification. In addition to this, a difference in amplification efficiency due to the thermal cycler used was also confirmed. In this test, as shown in Fig. 3, the fluorescence value of the positive sample with poor amplification and the nonspecific fluorescence value of the negative sample with excessive amplification may be almost the same value. Had to do. Thus, it is considered that stable gene amplification by using relatively high purity DNA is essential in this measurement system. In this regard, we plan to conduct additional tests with a larger number of specimens in the future.

  In Luminex method, it is possible to measure four types individually more easily, but since Luminex method can measure up to 100 types of beads simultaneously, 79 types including HLA-A and -B, And 44 types, including DRB1-PS1 and PS2, can be measured simultaneously, taking advantage of the high-throughput characteristics. Therefore, in this method, in the case of ABDR simultaneous determination, the measurement using the Luminex 100 system can be performed from 4 times to 2 times from the setting of the bead address and the performance of the determination software.

  The operation time of this measurement method was about 5 hours until the fluorescence value was detected with the Luminex device using the extracted DNA. Gene amplification conditions, reaction conditions with beads, etc. are the same for HLA-A, HLA-B and HLA-DRB1, so that 47 samples can be used simultaneously with two GeneAmp 9700 units and one Luminex main unit (for 96 samples) Measurement is possible (HLA-A and -B are combined into one well, and DRB1-PS1 and DRB1-PS2 are combined into one well, together with the negative control, to measure fluorescence with the Luminex100 system. 47 samples can be measured simultaneously). Furthermore, by preparing another set of this machine set, it is possible to measure 95 samples of A, B and DRB1 at the same time by one inspector, which is very useful as a method for judging a large number of samples. Conceivable.

Principle of Luminex measurement method using fluorescent beads. The flowchart of a measuring method. Fluorescence intensity of B17 beads. B showed the fluorescence intensity of 138 specimens for B17 beads, which is one of 46 types of probes. The vertical axis indicates the fluorescence intensity, and the horizontal axis indicates the number of specimens. Sample count includes negative controls and retests. In addition to the two specimens indicated by the arrows, a specimen around the cut-off value was reexamined.

Claims (6)

A gene detection method in which, when an oligo probe immobilized on a bead surface and a gene amplification product are hybridized, the probe solid phase bead and the gene amplification product are mixed and subjected to hybridization after heat denaturation by heating. In the Luminex method, which uses a probe solid phase bead with a detection oligo probe on a polystyrene fluorescent bead surface and an amplification product obtained by gene amplification using a gene sample as a template, a gene mutation is detected by a hybridization method. After mixing the probe solid phase beads and the amplification product, the denaturation of the amplification product into a single strand is defined as heat denaturation by heating, and after denaturation, the heat denaturation and hybridization are continuously performed. A genotyping method characterized by being performed. Among the HLA genotypes, to determine the class I HLA-A genotype,
Using a set of probes dedicated to HLA-A, amplified using a labeled primer set dedicated to HLA-A, and immobilized on fluorescent beads, the heat denaturation temperature condition is 95 ° C, and after heat denaturation The method according to claim 1 or 2, wherein the hybridization temperature condition is 52 ° C. Among the HLA genotypes, to determine the class I HLA-B genotype,
Using a set of probes dedicated to HLA-B, amplified using a labeled primer set dedicated to HLA-B, and immobilized on fluorescent beads, the temperature of heat denaturation by heating is 95 ° C, and after heat denaturation The method according to claim 1 or 2, wherein the hybridization temperature condition is 52 ° C. Among the HLA genotypes, class II HLA-DRB1 genotypes are determined by gene amplification using a labeled primer set dedicated to HLA-DRB1 and using a set of probes dedicated to HLA-DRB1 immobilized on fluorescent beads. The method according to claim 1 or 2, wherein the temperature condition for heat denaturation by heating is 95 ° C, and the temperature condition for hybridization after heat denaturation is 52 ° C. A detection kit comprising primers, probes, dNTPs, Taq DNA polymerase, and a buffer used in the method according to any one of claims 3 to 5 for determining an HLA genotype.