Four-digit allele genotyping of the HLA-A and HLA-B genes in Japanese patients with Behcet's disease by a PCR-SSOP-Luminex method

The present study represents the first four-digit allele genotyping of HLA-A and -B in Japanese Behcet's disease (BD) patients and controls using a new genotyping method (named the PCR-SSOP-Luminex method) to determine the association of certain HLA-A or -B alleles with BD. Peripheral blood lymphocytes were collected from 180 Japanese BD patients and 170 healthy controls. The genotype frequency of HLA-B*5101 was significantly increased in the patients (61.7%) as compared with the controls (15.9%) (Pc = 1 x 10(-16), OR = 8.5). When we recalculated the phenotype frequencies after excluding the HLA-B*51-positive patients and controls to account for the effects of the linkage disequilibrium and the abundance of the HLA-B*51 allele, the frequencies of HLA-A*2602 and HLA-B*3901 had a weak association in the patient group without HLA-B*51 as compared with the control group without HLA-B*51 (A*2602; Pc = 0.130, OR = 4.3, B*3901; Pc = 0.099, OR = 3.5). This study confirmed on the basis of using a new and more accurate genotyping method that Japanese BD patients have a strong primary association with HLA-B*5101. The significant increase of HLA-A*2602 and B*3901 in the patient group without HLA-B*51 suggests that these two alleles might also have some secondary influence on the onset of BD.     

Sequencing-based typing of HLA-B*51 alleles and the significant association of HLA-B*5101 and -B*5108 with Behçet's disease in Greek patients

Beh?et's disease (BD) is widely known to be strongly associated with human leukocyte antigen (HLA) B51 in many different ethnic groups.Recently, HLA-B51 allele typing of Greek BD patients was performed to study the distribution of B*5101-B*5107 alleles in this Greek population, the B51 antigen strongly associated with BD was found to be predominantly encoded by allele B*5101. As it is now known that the B51 antigen can be encoded by 21 alleles, B*5101-B*5121, we performed HLA-B*51 allele genotyping among 58 Greek patients with BD. After serological HLA typing, typing of HLA-B*51 alleles was performed using the polymerase chain reaction-sequencing-based typing (PCR-SBT) method. The frequency of the B51 antigen was found to be significantly higher in the patient group as compared with the control group (75.9% of patients vs 22.0% of controls. In the genotyping of B51 alleles, 34 out of 44 B51-positive patients possessed B*5101, 13 out of the 44 carried B*5108. In contrast, all of the 9 B51-positive normal controls carried B*5101. This study revealed a strong association between Greeks with BD, both B*5101, B*5108, provided important insights into the molecular mechanism underlying the association between HLA status, this disease.     

HLA-B*51 allele analysis by the PCR-SBT method and a strong association of HLA-B*5101 with Japanese patients with Behçet's disease

Abstract: Behçet's disease (BD) is known to be associated with human leukocyte antigen (HLA) B51 in many different ethnic groups. An increased incidence of HLA-B51 in the patient group has also been reported in a Japanese population. Recently, the B51 antigen has been identified to comprise 21 alleles, B*5101–B*5121. Further, not only HLA-B*5101 but also HLA-B*5108 were found to be relatively increased in the patient groups among Italian and Saudi Arabian populations. Therefore, we performed HLA-B*51 allele genotyping by the polymerase chain reaction-sequencing based typing (PCR-SBT) method in order to investigate whether there is any correlation of one particular B51-associated allele with Japanese BD. Ninety-six Japanese patients with BD and 132 healthy Japanese volunteers were enrolled in this study. As a result, the phenotype frequency of the B51 antigen was confirmed to be remarkably increased in the patient group as compared to the ethnically matched control group (59.4% in patients vs. 13.6% in controls; P c=0.0000000000098, R.R.=9.3). In the B*51 allele genotyping, 56 out of 57 B51-positive patients were defined as B*5101 and the remaining one was B*5102. In contrast, all of 18 B51-positive normal controls were B*5101. None of the Japanese patients and healthy controls carried the HLA-B*5108 allele. This study revealed that B*51 allelic distribution in Japanese was different from those in Italian and Saudi Arabian populations, and that the significantly high incidence of the HLA-B51 antigen in the Japanese BD patient group was mostly caused by the significant increase of the HLA-B*5101 allele.     

Allele frequencies and haplotypic associations defined by allelic DNA typing at HLA class I and class II loci in the Japanese population

HLA class I and class II allelic genotypes were determined in 371 unrelated individuals and 309 members of 81 families inhabiting the central Japan area. A total of 20 HLA-A alleles, 16 HLA-Cw alleles, 38 HLA-B alleles, 27 HLA-DRB1 alleles, 15 HLA-DQB1 alleles and 12 HLA-DPB1 alleles were detected. By the two-, three-, four-, five- and six-locus allelic association analyses extracted from the HLA-A to -DPB1 locus, 26 HLA-Cw-B haplotypes, 25 HLA-DRB1-DQB1 haplotypes, 42 HLA-Cw-B-DRB1 haplotypes, 37 HLA-Cw-B-DRB1-DQB1 haplotypes, 29 HLA-A-Cw-B-DRB1-DQB1 haplotypes and 21 HLA-A-Cw-B-DRB1-DQB1-DPB1 haplotypes with the frequencies of higher than 0.005 were recognized. Among 19 HLA-B alleles with the high allele frequencies (above 0.007), 9 HLA-B alleles, B*0702, B*1301, B*3701, B*3901, B*4006, B*4403, B*5201, B*5901 and B*6701 were found to be tightly associated with single HLA-Cw alleles. Most of HLA-DRB1 alleles showed strong associations with single HLA-DQB1 alleles, but DRB1*0802 and DRB1*1401 were associated with two different DQB1 alleles. Extended haplotypes carrying infrequent class I alleles with the allele frequencies of lower than 0.007 were defined by family studies. Gene frequencies and haplotypic associations within the entire HLA classical loci elucidated at the high resolution (four-digital) allelic level will provide useful information on anthropology, marrow donor registry, legal medicine and disease-association studies.     

Association of HLA-B51 and lack of association of class II alleles with Behcet''s disease

Eighty-one Behcet's disease patients have been studied for HLA association by HLA-DRB1, -DQA1, -DQB1 and -DPB1 genotyping with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and for NcoI RFLP in the tumor-necrosis factor (TNF beta) gene by Southern hybridization in addition to serological typing. In serological typing, the frequency of HLA-B51 was significantly increased in the patients. In PCR genotyping, there was a significant increase in the HLA-DRB1*0802, DQA1*0301 and DQB1*0303 alleles, whereas the frequencies of DRB1*1502, DQA1*0103, DQA1*0101, DQB1*0601 and DQB1*0501 showed a significant decrease in the patients. No significant difference was observed in any HLA-DPB1 alleles. Among them, B51 was found to be a genetic marker most strongly associated with Behcet's disease (p less than 0.00005, chi 2 = 46.47, pc[corrected p] less than 0.005). The positive and negative associations of class II alleles with the disease can be explained by linkage disequilibrium with B51, and do not reach statistical significance by the corrected p-value test. In NcoI RFLP typing in the TNF beta gene, 250 kb centromeric of the HLA-B gene, the frequency of a 5.5 kb fragment was considerably decreased in the patients when compared to the controls, although the decrease was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

HLA-DR/DQ/DP INTERACTIONS IN RHEUMATOID ARTHRITIS

Rheumatoid arthritis (RA) is associated with the presence of particular HLA-DRB1 alleles. In order to characterize HLA-DQB1 and/or -DPB1 alleles that contribute to disease susceptibility besides HLA-DRB1 alleles, we have analysed the HLA-DRB1, -DQB1 and -DPB1 polymorphism in 84 RA patients and 135 controls. HLA typing for HLA-DRB1 and -DQB1 alleles was performed using sequence-specific primers in combination with sequence-based typing. HLA-DPB1 alleles were characterized by reverse dot-blot hybridization. Our data confirm the predominant role of the (Q)R/KRAA sequence from AA position 70–74 of the HLA-DRB chain for disease susceptibility. In particular, the lysine (K) substitution at position 71 was highly significantly associated with RA. Analysis of the DQB1 locus revealed no association with RA when linkage disequilibrium between HLA-DRB1 and -DQB1 alleles was considered. In contrast, we observed an increased frequency of HLA-DPB1*0401 among (Q)R/KRAA-positive patients. (Q)R/KRAA-negative RA patients exihibited an overrepresentation of HLA-DPB1*0201 and HLA-DPB1*0601. Rheumatoid factor (RF) production correlated with the presense of the disease-associated (Q)R/KRAA amino acid cassette of the HLA-DRB chain. When HLA-DPB1 allele frequencies were compared between RF-positive and RF-negative RA patients, we observed an increased frequency of HLA-DPB1*0401 among RF-positive RA patients and HLA-DPB1*0201 among RF-negative patients. These results suggest that besides the predominent role of HLA-DR molecules in RA, HLA-DP molecules may have an influence on disease susceptibility and could modulate disease progression. HLA-DPB1*0401 may function in addition to HLA-DRB1*04, whereas HLA-DPB1*0201 and -DPB1*0601 may represent additional risk factors among (Q)R/KRAA-negative RA patients.     

Molecular genetic analysis of HLA class II alleles in Japanese patients with melanoma

Distribution of HLA-DQA, -DQB and -DPB alleles in ninety-six Japanese patients with melanoma was analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and the association between clinical parameters and the presence of certain HLA class II alleles investigated. The frequency of HLA-DQB 1*0302 was increased, while those of DQA1*0101(04), -DQA1*0401 and DRB1*0802 were decreased in melanoma patients compared with controls. Moreover, the frequency of HLA-DQA 1*0103 in patients with acral lentiginous melanoma was increased compared with controls. However, none of these HLA class II alleles showed significant positive or negative associations after correction of the P value. In addition, there was no correlation between these antigens and clinical parameters. These results indicate that HLA class II alleles may not contribute to a strong susceptibility to melanoma in the Japanese     

Associations of major histocompatibility complex class I chain-related molecule polymorphisms with Behcet's disease in Caucasian patients

HLA-B*51 is known to be associated with Behcet's disease (BD) in many ethnic groups. The pathogenic gene, however, may lie close to the HLA-B locus and therefore be in linkage disequilibrium with HLA-B*51. On the basis of the proximity of MIC genes to HLA-B, their expression pattern and their affinity for the activating NKG2D receptor on natural killer (NK) cells and gammadelta T cells, these molecules have been postulated as susceptibility factors in BD. DNA from 56 western European Caucasians with BD and 90 Caucasian controls were analysed by polymerase chain reaction using allele-specific primers for MICA and MICB alleles. An increased allele frequency of MICA*009 was found in the BD patient group (25.0%) when compared with the controls (7.2%). This was associated with a corresponding decrease in MICA*008 in the BD patients (36.6%) compared with the controls (46.7%), which was not significant. MICA*009 was strongly associated with the presence of HLA-B*51 in patients and controls. No significant difference in frequency of MICB alleles was found between patients and controls. Both HLA-B*51 and MICA*009 are strongly associated with BD in a pure Caucasian BD patient group, and the two alleles are in linkage disequilibrium. No MICB allele was found to associate significantly with the disease, an unexpected finding considering the close proximity of the MICA and MICB loci. Our results suggest that while MICB does not influence the development of BD, polymorphisms in MICA may be pathogenic, perhaps through the interaction with NK and gammadelta T cells.     

Frequencies and haplotype associations of non-expressed HLA alleles in ethnically diverse populations on the National Marrow Donor Program’s Be The Match Registry

HLA allele matching is critical to successful bone marrow transplantation between a patient and donor. Non-functional HLA alleles, so called ‘null alleles’, are not well described within a large population of well HLA-typed ethnically diverse individuals despite their impact on donor selection. A retrospective analysis was performed on 833,789 unrelated donors (URDs) in the National Marrow Donor Program’s Be The Match Registry® typed for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 by next-generation DNA sequencing. Results showed that null alleles occur in low frequency (2.30E−04) compared to expressed alleles. Their overall frequency ranged from 6.00E−07 to 9.25E−04 with a median of 1.20E-06. The expected allele associations were commonly observed for HLA-A*24:09N, HLA-B*51:11N, and HLA-C*04:09N; however, associations outside of the expected were also observed. Notably, 82% of the National Marrow Donor Program Registry URDs carrying HLA-A*24:11N showed a different HLA-C allele association, HLA-C*05:01, compared to the allele described by prior published work characterizing German donor populations, HLA-C*04:01. The frequencies of these observed null alleles and linkage disequilibrium information could be invaluable and helpful in guiding the HLA testing decisions.     

Significant associations of HLA-B*5101 and B*5108, and lack of association of class II alleles with Behçet's disease in Italian patients

Beh?et's disease has been known to be strongly associated with human leukocyte antigen (HLA) B51, one of the split antigens of HLA-B5. An increased incidence of HLA-B51 in the patient group has also been reported in an Italian population. Since the B51 antigen has been recently identified to comprise nine alleles, B*5101-B*5109, we performed HLA-B51 allele genotyping by the polymerase chain reaction-sequencing based typing (PCR-SBT) method as well as serological HLA-A and -B typing among 21 Italian patients with Beh?et's disease in order to investigate whether there is any correlation of one particular B51-associated allele with Behcet's disease. In addition, HLA class II genotyping was performed by the PCR-restriction fragment length polymorphism (RFLP) method. As a result, only the phenotype frequency of the B51 antigen was found to be significantly increased in the patient group as compared to the ethnically matched control group by the corrected P-value analysis (71.4% in patients vs. 17.9% in controls; chi2 = 14.26, Pc = 0.0042, R.R. = 11.5). In the B51 allele genotyping, 11 out of 15 B51-positive patients were B*5101 and the remaining four were B*5108, whereas all of 5 normal controls were B*5101, showing significant association of each allele with Beh?et's disease. No significant difference was observed between the patient and control groups in the HLA class II allelic distribution. This study revealed a strong association of Beh?et's disease in Italian with B*5108 as well as B*5101, providing important insight into the molecular mechanism underlying an HLA association with Beh?et's disease.     

HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1, DPB1) alleles and haplotypes in the Han from southern China

In this study, polymerase chain reaction-sequence-specific oligonucleotide prode (SSOP) typing results for the human leukocyte antigen (HLA) class I (A, B, and C) and class II (DRB1, DQA1, DQB1, and DPB1) loci in 264 individuals of the Han ethnic group from the Canton region of southern China are presented. The data are examined at the allele, genotype, and haplotype level. Common alleles at each of the loci are in keeping with those observed in similar populations, while the high-resolution typing methods used give additional details about allele frequency distributions not shown in previous studies. Twenty distinct alleles are seen at HLA-A in this population. The locus is dominated by the A*1101 allele, which is found here at a frequency of 0.266. The next three most common alleles, A*2402, A*3303, and A*0203, are each seen at frequencies of greater than 10%, and together, these four alleles account for roughly two-thirds of the total for HLA-A in this population. Fifty alleles are observed for HLA-B, 21 of which are singleton copies. The most common HLA-B alleles are B*4001 (f= 0.144), B*4601 (f= 0.119), B*5801 (f= 0.089), B*1301 (f= 0.068), B*1502 (f= 0.073), and B*3802 (f= 0.070). At the HLA-C locus, there are a total of 20 alleles. Four alleles (Cw*0702, Cw*0102, Cw*0801, and Cw*0304) are found at frequencies of greater than 10%, and together, these alleles comprise over 60% of the total. Overall, the class II loci are somewhat less diverse than class I. Twenty-eight distinct alleles are seen at DRB1, and the most common three, DRB1*0901, *1202, and *1501, are each seen at frequencies of greater than 10%. The DR4 lineage also shows extensive expansion in this population, with seven subtypes, representing one quarter of the diversity at this locus. Eight alleles are observed at DQA1; DQA1*0301 and 0102 are the most common alleles, with frequencies over 20%. The DQB1 locus is dominated by four alleles of the 03 lineage, which make up nearly half of the total. The two most common DQB1 alleles in this population are DQB1*0301 (f= 0.242) and DQB1*0303 (f= 0.15). Eighteen alleles are observed at DPB1; DPB1*0501 is the most common allele, with a frequency of 37%. The class I allele frequency distributions, expressed in terms of Watterson's (homozygosity) F-statistic, are all within expectations under neutrality, while there is evidence for balancing selection at DRB1, DQA1, and DQB1. Departures from Hardy-Weinberg expectations are observed for HLA-C and DRB1 in this population. Strong individual haplotypic associations are seen for all pairs of loci, and many of these occur at frequencies greater than 5%. In the class I region, several examples of HLA-B and -C loci in complete or near complete linkage disequilibrium (LD) are present, and the two most common, B*4601-Cw*0102 and B*5801-Cw*0302 account for more than 20% of the B-C haplotypes. Similarly, at class II, nearly all of the most common DR-DQ haplotypes are in nearly complete LD. The most common DRB1-DQB1 haplotypes are DRB1*0901-DQB1*0303 (f= 0.144) and DRB1*1202-DQB1*0301 (f= 0.131). The most common four locus class I and class II combined haplotypes are A*3303-B*5801-DRB1*0301-DPB1*0401 (f= 0.028) and A*0207-B*4601-DRB1*0901-DPB1*0501 (f= 0.026). The presentation of complete DNA typing for the class I loci and haplotype analysis in a large sample such as this can provide insights into the population history of the region and give useful data for HLA matching in transplantation and disease association studies in the Chinese population.     

HLA DRB1*15‐DPB1*05 haplotype: a susceptible gene marker for isocyanate‐induced occupational asthma?

BACKGROUND: There has been no study for evaluating the associations of human leukocyte antigen (HLA) class I and II alleles with toluene diisocyanate (TDI)-induced asthma in an Asian population. OBJECTIVE: The aim of this study was to investigate a susceptible or protective marker of HLA class I and II alleles in TDI-induced asthma. METHODS: Fifty-five patients with TDI-induced asthma patients (group I) showing positive responses on TDI bronchoprovocation test, 47 asymptomatic exposed subjects (group II) and 95 unexposed healthy nonatopic controls (group III) were enrolled in our study. HLA class I and II genotyping was done by the direct DNA sequencing method. RESULTS: The allelic frequency of C*09 (15.5%) was significantly higher in group I than in group III (6.8%, P = 0.019), but this statistical significance disappeared after correction was made for multiple comparisons. On two-locus and three-locus haplotype analysis, the allelic frequency of HLA DRB1*15-DPB1*05 in group I (10.6%) was significantly higher than that of group II (0%, P = 0.001) and group III (2.5%, P = 0.003). The allelic frequencies of HLA A*02-DRB1*15, A*02-DQB1*06, B*62-C*09 and A*02-DRB1*15-DQB1*06 were significantly higher in group I (8.5%, 10.3%, 8.2% and 6.8%, respectively) than those allelic frequencies of group III (1.3%, P = 0.002; 1.6%, P = 0.001; 0.6%, P < 0.0001; 0%, P < 0.0001, respectively). The allelic frequencies of HLA DQB1*06-DPB1*05 and DRB1*15-DQB1*06-DPB1*05 were significantly higher in group I (16.0% and 10.5%) than those in group II (2.5%, P = 0.001; 0%, P = 0.001), while the frequencies of DRB1*09-DPB1*05 and DRB1*09-DQB1*0303-DPB1*05 were significantly lower in group I (0% and 0%) than those of group II (7.4%, P = 0.004; 7.5%, P = 0.004). These differences remained statistically significant even after the correction for multiple comparisons. CONCLUSIONS: The HLA haplotype DRB1*15-DPB1*05 can be a susceptibility gene marker for the development of TDI-induced asthma among the exposed workers in the Korean population.     

Serological and molecular analysis of HLA class I and II alleles in Thai patients with psoriasis vulgaris

Abstract: The HLA class I and class II alleles in 67 patients with type I psoriasis vulgaris, 23 patients with type II psoriasis vulgaris and 140 healthy individuals were analyzed. The frequencies of HLA-A2, -B46, -B57 and DQB1*0303 were significantly increased in type I psoriasis compared to the controls (Pc<0.05). Molecular analysis of HLA-A2 alleles showed an increase in HLA-A*0207 and a decrease in HLA-A*0203 in type I psoriasis. HLA-DQBl*0301 was significantly decreased in type I psoriasis compared to the normal controls (Pc<0.05). No association of any alleles with type II psoriasis was observed. This data demonstrated two susceptible haplo-types: HLA-A1-B57-DRB1*0701-DQA1*0201-DQB1*0303 (AH57.1) and HLA-A2-B46-DRB1*0901-DQA1*0301-DQB1*0303 (AH46.1) for type I psoriasis in the Thai population. Besides, the haplotype AH46.1 was also associated with type II psoriasis.     

Polymorphism of human leukocyte antigen-DRB1, -DQB1, and -DPB1 genes of Shandong Han population in China

In the present study, polymerase chain reaction-sequence-based typing (PCR-SBT) was used to analyze human leukocyte antigen (HLA)-DRB1, -DQB1, and -DPB1 alleles of 98 unrelated healthy Shandong Han individuals. A total of 60 alleles, in which 28 in DRB1, 15 in DQB1 and 17 in DPB1 were found. Among the 28 detected DRB1 alleles, DRB1*150101, DRB1*070101, DRB1*090102, DRB1*120201, and DRB1*080302 were commonly observed, with frequencies of 16.3%, 11.2%, 10.2%, 8.2%, and 5.6%, respectively. The most predominant DQB1 allele was DQB1*030101/0309 with the frequency of 20.4%, followed by DQB1*0201/0202 (14.8%), DQB1*0602 (14.3%), DQB1*030302 (12.2%), and DQB1*060101/060103 (10.7%). Of the 17 detected DPB1 alleles, DPB1*0501 was the most frequent allele with the frequency of 37.2%. DPB1*020102 (18.4%), DPB1*040101 (11.2%), DPB1*0402 (7.1%), and DPB1*1701 (6.6%) were also very frequent alleles. A total of 53 estimated DRB1-DQB1 two-locus haplotypes were observed in Shandong Han population, of which DRB1*150101-DQB1*0602 was the most predominant, followed by DRB1*090102-DQB1*030302, DRB1*070101-DQB1*0201/0202 DRB1*120201-DQB1*030101/0309, and DRB1*080302- DQB1*060101/060103. The distribution of the HLA class II alleles and haplotypes frequencies as well as the dendrogram showed that the Shandong Han population belongs to the northern group of Chinese. The data have implications for anthropological studies and disease associations.     

Allelic and haplotypic diversity of HLA-A, -B, -C, -DRB1, and -DQB1 genes in the Korean population

High-resolution human leukocyte antigen (HLA) typing exposes the unique patterns of HLA allele and haplotype frequencies in each population. In this study, HLA-A, -B, -C, -DRB1, and -DQB1 genotypes were analyzed in 485 apparently unrelated healthy Korean individuals. A total of 20 HLA-A, 43 HLA-B, 21 HLA-C, 31 HLA-DRB1, and 14 HLA-DQB1 alleles were identified. Eleven alleles (A*0201, A*1101, A*2402, A*3303, B*1501, Cw*0102, Cw*0302, Cw*0303, DQB1*0301, DQB1*0302, and DQB1*0303) were found in more than 10% of the population. In each serologic group, a maximum of three alleles were found with several exceptions (A2, B62, DR4, DR14, and DQ6). In each serologic group exhibiting multiple alleles, two major alleles were present at 62-96% (i.e. A*0201 and A*0206 comprise 85% of A2-positive alleles). Multiple-locus haplotypes estimated by the maximum likelihood method revealed 51 A-C, 43 C-B, 52 B-DRB1, 34 DRB1-DQB1, 48 A-C-B, 42 C-B-DRB1, 46 B-DRB1-DQB1, and 30 A-C-B-DRB1-DQB1 haplotypes with frequencies of more than 0.5%. In spite of their high polymorphism in B and DRB1, identification of relatively small numbers of two-locus (B-C and DRB1-DQB1) haplotypes suggested strong associations of those two loci, respectively. Five-locus haplotypes defined by high-resolution DNA typing correlated well with previously identified serology-based haplotypes in the population. The five most frequent haplotypes were: A*3303-Cw*1403-B*4403-DRB1*1302-DQB1*0604 (4.2%), A*3303-Cw*0701/6-B*4403-DRB1*0701-DQB1*0201/2 (3.0%), A*3303-Cw*0302-B*5801-DRB1*1302-DQB1*0609 (3.0%), A*2402-Cw*0702-B*0702-DRB1*0101-DQB1*0501 (2.9%), and A*3001-Cw*0602-B*1302-DRB1*0701-DQB1*0201/2 (2.7%). Several sets of allele level haplotypes that could not be discriminated by routine HLA-A, -B, and -DRB1 low-resolution typing originated from allelic diversity of A2, B61, DR4, and DR8 serologic groups. Information obtained in this study will be useful for medical and forensic applications as well as in anthropology.     

HLA-DRB1, DQB1 and DPB1 polymorphism in the Naxi ethnic group of South-western China

Polymorphism of HLA-DRB1, DQB1 and DPB1 was revealed with a sequencing-based typing (SBT) method in unrelated healthy volunteers from the Naxi ethnic group. Among the 43 DRB1 alleles detected, the most common allele was DRB1*12021 with a frequency of 17%, followed by DRB1*08032, DRB1*09012 and DRB1*1404 with frequencies of 8.5%, 7.4% and 7.4%, respectively. Among 23 DQB1 alleles detected, the most frequent DQB1 allele was DQB1*03011/0309 (21.9%), followed by DQB1*0502 (16.4%) and DQB1*05031 (9.6%). For the DPB1 locus, the most common alleles were DPB1*0501 (25.5%), DPB1*0402 (14.6%) and DPB1*02012 (12.0%). The most common DRB1-DQB1-DPB1 haplotype was DRB1*1404-DQB1*05031-DPB1*0402 with a frequency of 5.26%, followed by the DRB1*08032-DQB1*06011-DPB1*1301 (3.51%). The distribution characteristics of the HLA class II alleles revealed that the Naxi ethnic group belonged to the Southern group of Chinese.     

A weak association of HLA-B*2702 with Behçet's disease

This study aimed to analyse the association of HLA-B alleles other than -B51 with Beh?et's disease (BD). We also investigated the frequency of HLA-B alleles sharing the same natural killer cell immunoglobulin-like receptor (KIR) binding sequence with HLA-B51. Broad-genotyping of HLA-B locus by PCR-SSOP in 174 Turkish BD patients and 191 healthy controls confirmed the strong association of B*51 with BD (60.9% in BD patients, 24.6% in healthy controls, OR = 4.78). No other HLA-B allele was identified showing an association with BD after adjusting for multiple testing or by using relative predispositional effects (RPE) analysis after the deletion of B*51. HLA-B alleles reacting with the sequence specific oligonucleotide probe 23, which corresponds to the KIR binding site of B*51, were found to be positive in 127 BD patients (73%) and 90 controls (47%) (OR = 3.03, 95% CI 2-4.7). The repeated RPE analysis after separating HLA-B alleles carrying B51-KIR binding sequence as distinct alleles within a broad-type allele group revealed B*2702 allele as the only allele showing an association with BD after the deletion of B*51. Selective increase of B*2702, the only B*27 allele carrying the same KIR binding sequence with B*51, warrants investigation of the possibility of interaction of HLA molecules with KIRs on NK or other T cells in the pathogenesis of BD.     

HLA-associated production of anti-DFS70/LEDGF autoantibodies and systemic autoimmune disease

Autoantibodies against DFS70/LEDGF, which is also known as an important partner of HIV-1 integrase, are found in 10% of healthy Japanese people, but in only approximately 2% of patients with systemic autoimmune disease (SAD). We wished to characterize the association of HLA class II alleles with the presence of autoantibodies against this molecule. MHC class II genes (DR, DQ, and DP alleles) were analyzed by the polymerase chain reaction-sequence specific primer method in 24 individuals with anti-DFS70 antibodies. The frequencies of HLA-DRB1*0410, -DQB1*0402, and -DPB1*0301 were increased in anti-DFS70 Ab-positive patients, while HLA-DQB1*0302 was decreased compared to Japanese controls. All anti-DFS70 Ab-positive individuals expressed at least one HLA-DQB1 allele with an aspartic acid at residue 57. The immunogenetic background of Japanese individuals with anti-DFS70 antibodies differs from that of patients with SAD. HLA class II genes influence the production of anti-DFS70 antibodies among individuals with various clinical manifestations.     

HLA-DPB1, -DRB1, and -DQB1 polymorphism defined in Ewenki ethnic minority of China Inner Mongolia Autonomous Region

In the present study, DNA typing for human leucocyte antigen (HLA)-DPB1, -DRB1, and -DQB1 was performed using polymerase chain reaction-sequence-based-typing (PCR-SBT) method on 94 randomly selected, healthy, unrelated individuals from the Ewenki ethnic population in Inner Mongolia Autonomous Region of China. A total of 64 alleles: 25 in DRB1, 19 in DQB1 and 20 in DPB1, were found. Among the 25 detected DRB1 alleles, DRB1*090102, DRB1*030101, DRB1*040101, DRB1*070101, and DRB1*120101/1206 were commonly observed, with frequencies of 16.0%, 13.3%, 10.1%, 7.4%, and 7.4%, respectively. The most predominant DQB1 allele was DQB1*030101/0309 with the frequency of 27.7%, followed by DQB1*0201/0202 (19.7%), DQB1*030302 (12.8%), DQB1*060101/060103 (6.4%), and DQB1*050201 (5.9%). Of the 20 detected DPB1 alleles, DPB1*020102 was the most frequent allele with the frequency of 25.5%. DPB1*0402 (21.3%), DPB1*0401 (20.2%), DPB1*0501 (10.6%) and DPB1*4101 (3.7%) were also very frequent alleles. The most frequent two-locus haplotypes observed in the Ewenki were: DRB1*030101-DQB1*0201/0202(10.7%), DRB1*090102-DQB1*03032(9.8%), DRB1*070101-DQB1*0201/0202 (5.5%), DRB1*070101-DQB1*030302 (5.2%) and DRB1*120101/1206-DQB1*030101/0309 (4.6%). The distribution of the HLA class II alleles and haplotypes frequencies as well as the dendrogram showed that the Ewenki population belongs to the northern group of Chinese.     

Allelic diversity and affinity variants of MICA are imbalanced in Spanish patients with Behçet's disease

The aetiology of Behçet's disease (BD) is still unknown, but genetic and environmental factors are involved. HLA‐B*51 is considered a susceptibility marker and some MICA alleles have also been associated. Cytotoxic T lymphocytes have been suggested as responsible for BD lesions by engaging MICA through NKG2D surface molecules. In the present study, HLA‐B and MICA alleles were typed by polymerase chain reaction using sequence‐specific primers, in 165 healthy Spanish controls and 42 BD patients. In the healthy group, MICA*008 (28.48%), MICA*004 (17.58%), MICA*002 (14.24%) and MICA*009 (9.39%) were the predominant alleles and the most common haplotype was MICA*004‐B*44 (12.12%). MICA*001 (5.15%), MICA*004, MICA*011 (4.54%) and MICA*018 (5.15%) were more frequent, and MICA*010 (1.81%) and MICA*008 were less prevalent than in other Caucasoid populations. Similar results have been reported in North African individuals and this could support the hypothesis of a common ancestral origin of both populations. The frequencies of MICA*009 and MICA*019 were significantly increased in our BD patients in comparison with controls: 22.62% versus 9.39% and 10.71% versus 1.81% respectively. The increase of MICA*019 had not been described in other BD cohorts, and it corroborates the genetic heterogeneity at MICA locus in BD patients. High‐affinity MICA alleles for NKG2D were more frequent in controls than in patients. Moreover, high‐affinity alleles were not found in homozygous BD patients. These results argue against the hypothesis of an autoaggressive response in BD patients through MICA–NKG2D interactions.