HLA class II polymorphism in autochthonous population of Gorski kotar, Croatia

The aim of this study was to examine frequencies and haplotypic associations of HLA class II alleles in autochthonous population of Gorski kotar (Croatia). HLA-DRB1, -DQA1 and -DQB1 alleles were determined by DNA based PCR typing in 63 unrelated inhabitants from Gorski kotar whose parents and ancestors were born and lived in tested area for at least over four generations. A total of 13 HLA-DRB1, 12 DQA1 and 14 DQB1 alleles were identified. The most frequent HLA class II genes in Gorski kotar population are: HLA-DRB1*13 (af = 0.150), -DRB1*03 (af = 0.142), -DRB1*07 (af = 0.119), and -DRB1*11 (af = 0.119), HLA-DQA1*0501 (af = 0.278), -DQA1*0102 (af = 0.183), -DQA1*0201 (af = 0.127) and HLA-DQB1*0301 (af = 0.157), -DQB1*0201 (af = 0.139), -DQB1*0501 (af = 0.111). We have identified 24 HLA class II three-locus haplotypes. The most common haplotypes in Gorski kotar population are DRB1*03-DQA* 0501-DQB1*0201 (0.120), DRB1*11-DQA1*0501-DQB1*0301 (0.111) and DRB1*07-DQA1*0201-DQB1*0202 (0.094). The allelic frequencies and populations distance dendrogram revealed the closest relationships of Gorski kotar population with Slovenians, Germans, Hungarians and general Croatian population, which is the result of turbulent migrations within this microregion during history.     

Polymorphisms of HLA-DRB1, -DQA1 and -DQB1 in Inhabitants of Astana,the Capital City of Kazakhstan

Background

Kazakhstan has been inhabited by different populations, such as the Kazakh, Kyrgyz, Uzbek and others. Here we investigate allelic and haplotypic polymorphisms of human leukocyte antigen (HLA) genes at DRB1, DQA1 and DQB1 loci in the Kazakh ethnic group, and their genetic relationship between world populations.

Methodology/Principal Findings

A total of 157 unrelated Kazakh ethnic individuals from Astana were genotyped using sequence based typing (SBT-Method) for HLA-DRB1, -DQA1 and -DQB1 loci. Allele frequencies, neighbor-joining method, and multidimensional scaling analysis have been obtained for comparison with other world populations. Statistical analyses were performed using Arlequin v3.11. Applying the software PAST v. 2.17 the resulting genetic distance matrix was used for a multidimensional scaling analysis (MDS). Respectively 37, 17 and 19 alleles were observed at HLA-DRB1, -DQA1 and -DQB1 loci. The most frequent alleles were HLA-DRB1*07:01 (13.1%), HLA-DQA1*03:01 (13.1%) and HLA-DQB1*03:01 (17.6%). In the observed group of Kazakhs DRB1*07:01-DQA1*02:01-DQB1*02:01 (8.0%) was the most common three loci haplotype. DRB1*10:01-DQB1*05:01 showed the strongest linkage disequilibrium. The Kazakh population shows genetic kinship with the Kazakhs from China, Uyghurs, Mongolians, Todzhinians, Tuvinians and as well as with other Siberians and Asians.

Conclusions/Significance

The HLA-DRB1, -DQA1and -DQB1 loci are highly polymorphic in the Kazakh population, and this population has the closest relationship with other Asian and Siberian populations.     

High resolution molecular typing of HLA class II region in the population of the island of Krk, Croatia

The HLA class II alleles (DRB1, DRB3, DRB5, DQA1, and DQB1) and haplotypic associations were studied in the population of the island of Krk using the PCR-SSOP method and the 12th International Histocompatibility Workshop primers and probes. Allele and haplotypic frequencies were compared with the general Croatian population. Significant differences were observed between the population of the island of Krk and Croatians for: a) three broad specificities at DRB1 locus (DRB1*01, *15, and *07), b) one allele at DRB3 locus (DRB3*0301), c) one allele at DQA1 locus (DQA1*0201), d) one allele at DQB1 locus (DQB1*0303). Four unusual haplotypic associations, which have not yet been described in the Croatian population, DRB1*1301-DQA1*0103-DQB1*0607, DRB1*1302-DQA1*0102-DQB1*0605, DRB1*1305-DQA1*0102-DQB1*0605 and DRB1*1305-DQA1*0103-DQB1*0603 were observed in the population from the island of Krk.     

Genetic history of Aleuts of the Komandor islands from results of analyzing variability of class II HLA genes

Variability of the HLA class II genes (alleles of the DRB1, DQA1, and DQB1 loci) was investigated in a sample of Aleuts of the Commanders (n = 31), whose ancestors inhabited the Commander Islands for many thousand years. Among 19 haplotypes revealed in Aleuts of the Commanders, at most eight were inherited from the native inhabitants of the Commander Islands. Five of these haplotypes (DRB1*0401-DQA1*0301-DQB1*0301, DRB1*1401-DQA1*0101-DQB1*0503, DRB1*0802-DQA1*0401-DQB1*0402, DRB1*1101-DQA1*0501-DQB1*0301, and DRB1*1201-DQA1*0501-DQB1*0301) were typical of Beringian Mongoloids, i.e., Coastal Chukchi and Koryaks, as well as Siberian and Alaskan Eskimos. Genetic contribution of the immigrants to the genetic pool of proper Aleuts constituted about 52%. Phylogenetic analysis based on Transberingian distribution of the DRB1 allele frequencies favored the hypothesis on the common origin of Paleo-Aleuts, Paleo-Eskimos, and the Indians from the northwestern North America, whose direct ancestors survived in Beringian/southwestern Alaskan coastal refugia during the late Ice Age.     

Susceptibility alleles and haplotypes of human leukocyte antigen DRB1, DQA1, and DQB1 in autoimmune polyglandular syndrome type III in Japanese population

BACKGROUND: It has been reported that HLA class II haplotypes DRB1*0405-DQA1*0303-DQB1*0401 and DRB1*0901-DQA1*0302-DQB1*0303 are major susceptibility haplotypes for type 1 diabetes mellitus (DM) in Japanese population. However, little has been reported on the susceptibility HLA class II haplotypes in Japanese patients with autoimmune polyglandular syndrome type II and type III (APS III). PATIENTS AND METHODS: HLA class II haplotypes of DRB1-DQA1-DQB1 in 31 patients with APS III, 14 patients with Hashimoto's thyroiditis alone, and 15 patients with Graves' disease alone were examined in Japanese population. APS III patients were divided into three groups (A, B, and C) depending on the combination of autoimmune endocrine diseases. RESULTS: In 13 APS III patients with both Hashimoto's thyroiditis and type 1 DM (group A), the haplotype frequencies of the HLA DRB1*0802-DQA1*0401-DQB1*0402 and DRB1*0901-DQA1*0302-DQB1*0303 were significantly higher than in the controls. In patients with Hashimoto's thyroiditis alone, the haplotype frequency of DRB1*0901-DQA1*0302-DQB1*0303 was significantly higher than in controls, whereas the frequency of DRB1*0802-DQA1*0401-DQB1*0402 did not differ significantly from those in the controls. In 11 APS III patients with both Graves' disease and type 1 DM (group B), the haplotype frequencies of HLA DRB1*0405-DQA1*0303-DQB1*0401 and DRB1*0802-DQA1*0301-DQB1*0302 were significantly higher than in controls. In patients with Graves' disease alone, the haplotype frequency of DRB1*0803-DQA1*0103-DQB1*0601 were significantly higher than those in controls, suggesting that the susceptibility haplotypes for group B APS III differed from those for Graves' disease alone. In 7 APS III patients with both autoimmune thyroid diseases and pituitary disorders (group C), the haplotype frequency of HLA DRB1*0405-DQA1*0303-DQB1*0401 was significantly higher than in controls. CONCLUSIONS: Susceptible HLA class II haplotypes of DRB1-DQA1-DQB1 for APS III differ between the Japanese and Caucasian populations. More interestingly, the susceptible HLA class II haplotypes differ among the three types of Japanese APS III and are not merely a combination of susceptibility haplotypes of each endocrine disease.     

HLA class II gene and haplotype diversity in the population of the island of Hvar, Croatia

The DRB1, DRB3, DRB5, DQA1 and DQB1 allele polymorphisms were analysed in 3 western and 3 eastern villages of the island of Hvar using PCR-SSOP method and 12th International Workshop primers and probes. Three DQB1 alleles (*0304, *0305, *0607) detected in the population of the island of Hvar (HP) have not yet been observed in general Croatian population (GCP). Significant differences were observed between two regions of Hvar for: a) DRB1*0701 allele (p < 0.001), b) DQA1*0201 allele (p < 0.01), and c) DRB1*0101-DQA1*0101-DQB1*0501 haplotypic association (p < 0.05). Two unusual haplotypic associations, which have not yet been described in general Croatian population (GCP), DRB1*0101-DQA1*0102-DQB1*0501 and DRB1*1501-DQA1 *0102-DQB1*0604 were observed in the population from the island of Hvar (HP). Measures of genetic kinship and genetic distances revealed isolation and clusterization which coincides with the known ethnohistorical, as well as biological and biocultural data obtained from a series of previous investigations. The five studied village subpopulations formed two clusters (East-West) to which the far eastern village (with the highest rii of 0.0407) joined later, thus indicating possible impact of historical immigrations from the mainland.     

Genetic History of Aleuts of the Commander Islands as Revealed by the Analysis of the HLA Class II Gene Variability

Variability of the HLA class II genes (alleles of the DRB1, DQA1, and DQB1 loci) was investigated in a sample of Aleuts of the Commanders (n = 31), whose ancestors inhabited the Commander Islands for many thousand years. Among 19 haplotypes revealed in the Aleuts of the Commanders, at most eight were inherited from the native inhabitants of the Commander Islands. Five of these haplotypes (DRB1*0401-DQA1*0301-DQB1*0301, DRB1*1401-DQA1*0101-DQB1*0503, DRB1*0802-DQA1*0401-DQB1*0402, DRB1*1101-DQA1*0501-DQB1*0301, and DRB1*1201-DQA1*0501-DQB1*0301) were typical of Beringian Mongoloids, i.e., Coastal Chukchi and Koryaks, as well as Siberian and Alaskan Eskimos. Genetic contribution of the immigrants to the genetic pool of the proper Aleuts constituted about 52%. Phylogenetic analysis based on Transberingian distribution of the DRB1 allele frequencies favored the hypothesis on the common origin of the Paleo-Aleuts, Paleo-Eskimos, and the Indians from the northwestern North America, whose direct ancestors survived in Beringian/southwestern Alaskan coastal refugia during the late Ice Age.     

Polymorphism, recombination, and linkage disequilibrium within the HLA class II region.

Thirty-nine CEPH (Centre d'Etude du Polymorphisme Humain) families, comprised of 502 individuals, have been typed for the HLA class II genes DRB1, DQA1, DQB1, and DPB1 using nonradioactive sequence-specific oligonucleotide probes to analyze polymerase chain reaction amplified DNA. This population, which consists of 266 independent chromosomes, contains 27 DRB1, 7 DQA1, 12 DQB1, and 17 DPB1 alleles. Analysis of the distribution of allele frequencies using the homozygosity statistic, which gives an indication of past selection pressures, suggests that balancing selection has acted on the DRB1, DQA1, and DQB1 loci. The distribution of DPB1 alleles, however, suggests a different evolutionary past. Family data permits the estimation of recombination rates and the unambiguous assignment of haplotypes. No recombinants were found between DRB1, DQA1, and DQB1; however, recombinants were detected between DQB1 and DPB1, resulting in an estimated recombination fraction of greater than or equal to 0.008 +/- 0.004. Only 33 distinct DRB1-DQA1-DQB1 haplotypes were found in this population which illustrates the extreme nonrandom haplotypic association of alleles at these loci. A few of these haplotypes are unusual (previously unreported) for a Caucasian population and most likely result from past recombination events between the DR and DQ subregions. Examination of disequilibrium across the HLA region using these data and the available serologic HLA-A and HLA-B types of these samples shows that global disequilibrium between these loci declines with the recombination fraction, approaching statistic nonsignificance at the most distant interval, HLA-A to HLA-DP.DR-DQ haplotypes in linkage disequilibrium with DPB1 and B are noted and, finally, the evolutionary origin of certain class II haplotypes is addressed.     

HLA class II DR-DQ amino acids and insulin-dependent diabetes mellitus: application of the haplotype method.

Insulin-dependent diabetes mellitus (IDDM) HLA class II DRB1-DQA1-DQB1 data from four populations (Norwegian, Sardinian, Mexican American, and Taiwanese) have been analyzed to detect the amino acids involved in the disease process. The combination of sites DRB1#67 and 86; DQA1#47; and DQB1#9, 26, 57, and 70 predicts the IDDM component in these four populations, when the results and criteria of the haplotype method for amino acids, developed in the companion paper in this issue of the Journal, are used. The following sites, either individually, or in various combinations, previously have been suggested as IDDM components: DRB1#57, 70, 71, and 86; DQA1#52; and DQB1#13, 45, and 57 (DQB1#13 and 45 correlates 100% with DQB1#9 and 26). We propose that DQA1#47 is a better predictor of IDDM than is the previously suggested DQA1#52, and we add DRB1#67 and DQB1#70 to the HLA DR-DQ IDDM amino acids. We do not claim to have identified all HLA DR-DQ amino acids-or highly correlated sites-involved in IDDM. The frequencies and predisposing/protective effects of the haplotypes defined by these seven sites have been compared, and the effects on IDDM are consistent across the populations. The strongest susceptible effects came from haplotypes DRB1 *0301/DQA1 *0501/ DQB1*0201 and DRB1*0401-5-7-8/DQA1*0301/ DQB1*0302. The number of strong protective haplotypes observed was larger than the number of susceptible ones; some of the predisposing haplotypes were present in only one or two populations. Although the sites under consideration do not necessarily have a functional involvement in IDDM, they should be highly associated with such sites and should prove to be useful in risk assessment.     

HLA and Celiac Disease Susceptibility: New Genetic Factors Bring Open Questions about the HLA Influence and Gene-Dosage Effects

Celiac disease (CD) is a chronic inflammatory disorder triggered after gluten ingestion in genetically susceptible individuals. The major genetic determinants are HLA-DQA1*05 and HLA-DQB1*02, which encode the DQ2 heterodimer. These alleles are commonly inherited in cis with DRB1*03∶01, which is associated with numerous immune-related disorders, in some cases contributing with a different amount of risk depending on the haplotype context. We aimed at investigating those possible differences involving DRB1*03∶01-carrying haplotypes in CD susceptibility. A family (274 trios) and a case-control sample (369 CD cases/461 controls) were analyzed. DRB1*03∶01-carrying individuals were classified according to the haplotype present (ancestral haplotype (AH) 8.1, AH 18.2 or non-conserved haplotype) after genotyping of HLA-DRB1, -DQA1, -DQB1, -B8, TNF -308, TNF -376 and the TNFa and TNFb microsatellites. We observe that the AH 8.1 confers higher risk than the remaining DRB1*03∶01-carrying haplotypes, and this effect only involves individuals possessing a single copy of DQB1*02. CD risk for these individuals is similar to the one conferred by inherit DQA1*05 and DQB1*02 in trans. It seems that an additional CD susceptibility factor is present in the AH 8.1 but not in other DRB1*03∶01-carrying haplotypes. This factor could be shared with individuals possessing DQ2.5 trans, according to the similar risk observed in those two groups of individuals.     

Genetic and immunologic aspects of type 1 diabetes mellitus

Prediction of type 1 diabetes mellitus (IDDM) and its identification in preclinical period is one of the central problems in modern medicine. They are based comprehensive genetic, immunologic and metabolic evaluations. We observed four hundred seven first-degree relatives of patients with IDDM (240 families in which one of the children or one of the parents had IDDM) have been included in the study. The study of HLA-DQA1, HLA-DQB1 polymorphic alleles and DRB1 genes and their combinations. The genetic study included searching HLA loci (HLA-DQA1, HLA-DQB1 polymorphic alleles and DRB1 genes) loci. To evaluate the genetic risk two approaches we used: first--carrying predisposing HLA-DQ alleles and DRB1-genes and it's combination (mainly associated in Russian population was DRB1*04-DQB1*0302, DRB1*04-DQA1*0301, DQA1*0301-DQB1*0302, DQA1*0301-DQB1*0302 and four susceptible alleles in A- and B- chains (Asp 57-, Arg 52+)) and second--IBD (identity by descent), in Russian population HLA-identical for 2 haplotypes sibs had risk of development of IDDM of 18%, for 1 haplotype--3%, for 0 haplotype-0.9%. The antibodies (ICA, IAA) prevalence rate has not depended on availability of predisposing HLA-DQ alleles and DRB1-genes and haploidentity of normal sibs and sibs with IDDM. However, GADA prevalence rate in groups having high predisposed alleles has been noticed as significantly higher (28.6%) comparing with 7.7% in groups that had no predisposing alleles (p < 0.05). The comparison of antibodies prevalence rate to sibs HLA-identity has shown the significant increase or GADA prevalence rate in group of siblings identical for one haplotype comparing with non-identical sibs (27.3% and 0% respectively, p < 0.001).     

A new<Emphasis Type="Italic"> DR7-DQ8</Emphasis> haplotype resulting from a recombination between the<Emphasis Type="Italic"> DQA1</Emphasis> and<Emphasis Type="Italic"> DQB1</Emphasis> loci in a leukemic patient of Caucasoid origin

Meiotic recombinations within the HLA-DR/DQ subregion are seldomly observed. However the high number of unusual DRB1-DQB1 allelic combinations underline the importance of crossover in shaping the class II haplotypic diversity. We present here the first report of a DQA1-DQB1 recombination event in a leukemic patient as detected by complete class II molecular typing of the family, including analysis of the DQCAR microsatellite. The recombination that occurred on the maternal chromosomes led to the unusual DR7-DQ8 haplotype characterized by the DRB1*0701-DRB4*01030102N-DQA1*0201-DQB1*0302 alleles. Because the patient had no HLA-identical sibling donor, a search for an unrelated hematopoietic stem cell donor was initiated. Out of three potential donors, only one HLA-A/-B/-C/DRB1-compatible but DQB1-mismatched donor could be identified.     

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.     

In adult onset myositis, the presence of interstitial lung disease and myositis specific/associated antibodies are governed by HLA class II haplotype, rather than by myositis subtype

The aim of this study was to investigate HLA class II associations in polymyositis (PM) and dermatomyositis (DM), and to determine how these associations influence clinical and serological differences. DNA samples were obtained from 225 UK Caucasian idiopathic inflammatory myopathy patients (PM = 117, DM = 108) and compared with 537 randomly selected UK Caucasian controls. All cases had also been assessed for the presence of related malignancy and interstitial lung disease (ILD), and a number of myositis-specific/myositis-associated antibodies (MSAs/MAAs). Subjects were genotyped for HLA-DRB1, DQA1 and DQB1. HLA-DRB1*03, DQA1*05 and DQB1*02 were associated with an increased risk for both PM and DM. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype demonstrated strong association with ILD, irrespective of myositis subtype or presence of anti-aminoacyl-transfer RNA synthetase antibodies. The HLA-DRB1*07-DQA1*02-DQB1*02 haplotype was associated with risk for anti-Mi-2 antibodies, and discriminated PM from DM (odds ratio 0.3, 95% confidence interval 0.1-0.6), even in anti-Mi-2 negative patients. Other MSA/MAAs showed specific associations with other HLA class II haplotypes, irrespective of myositis subtype. There were no genotype, haplotype or serological associations with malignancy. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype associations appear to not only govern disease susceptibility in Caucasian PM/DM patients, but also phenotypic features common to PM/DM. Though strongly associated with anti-Mi-2 antibodies, the HLA-DRB1*07-DQA1*02-DQB1*02 haplotype shows differential associations with PM/DM disease susceptibility. In conclusion, these findings support the notion that myositis patients with differing myositis serology have different immunogenetic profiles, and that these profiles may define specific myositis subtypes.     

The role of HLA class II genes in insulin-dependent diabetes mellitus: molecular analysis of 180 Caucasian,multiplex families.

We report here our analysis of HLA class II alleles in 180 Caucasian nuclear families with at least two children with insulin-dependent diabetes mellitus (IDDM). DRB1, DQA1, DQB1, and DPB1 genotypes were determined with PCR/sequence-specific oligonucleotide probe typing methods. The data allowed unambiguous determination of four-locus haplotypes in all but three of the families. Consistent with other studies, our data indicate an increase in DR3/DR4, DR3/DR3, and DR4/DR4 genotypes in patients compared to controls. In addition, we found an increase in DR1/DR4, DR1/DR3, and DR4/DR8 genotypes. While the frequency of DQB1*0302 on DR4 haplotypes is dramatically increased in DR3/DR4 patients, DR4 haplotypes in DR1/DR4 patients exhibit frequencies of DQB1*0302 and DQB1*0301 more closely resembling those in control populations. The protective effect of DR2 is evident in this data set and is limited to the common DRB1*1501-DQB1*0602 haplotype. Most DR2+ patients carry the less common DR2 haplotype DRB1*1601-DQB1*0502, which is not decreased in patients relative to controls. DPB1 also appears to play a role in disease susceptibility. DPB1*0301 is increased in patients (P < .001) and may contribute to the disease risk of a number of different DR-DQ haplotypes. DPB1*0101, found almost exclusively on DR3 haplotypes in patients, is slightly increased, and maternal transmissions of DRB1*0301-DPB1*0101 haplotypes to affected children occur twice as frequently as do paternal transmissions. Transmissions of DR3 haplotypes carrying other DPB1 alleles occur at approximately equal maternal and paternal frequencies. The complex, multigenic nature of HLA class II-associated IDDM susceptibility is evident from these data.     

HLA-DQ-restricted CD4+ T cells specific to streptococcal antigen present in low but not in high responders.

We have found that the low immune response to streptococcal cell wall Ag (SCW) was inherited as a dominant trait and was linked to HLA, as deduced from family analysis. In the present report, HLA class II alleles of healthy donors were determined by serology and DNA typing to identify the HLA alleles controlling low or high immune responses to SCW. HLA-DR2-DQA1*0102-DQB1*0602(DQw6)-Dw2 haplotype or HLA-DR2-DQA1*0103-DQB1*0601(DQw6)-DW12 haplotype was increased in frequency in the low responders and the frequency of HLA-DR4-DRw53-DQA1*0301-DQB1*0401(DQw4)-Dw15 haplotype or HLA-DR9-DRw53-DQA1*0301-DQB1*0303(DQw3)-Dw23 haplotype was increased in the high responders to SCW. Homozygotes of either DQA1*0102 or DQA1*0103 exhibited a low responsiveness to SCW and those of DQA1*0301 were high responders. The heterozygotes of DQA1*0102 or 0103 and DQA1*0301 showed a low response to SCW, thereby confirming that the HLA-linked gene controls the low response to SCW, as a dominant trait. Using mouse L cell transfectants expressing a single class II molecule as the APC, we found that DQw6(DQA1*0103 DQB1*0601) from the low responder haplotype (DR2-DQA1*0103-DQB1*0601(DQw6)-Dw12) activated SCW-specific T cell lines whereas DQw4(DQA1*0301 DQB1*0401) from the high responder haplotype (DR4-DRw53-DQA1*0301-DQB1*0401(DQw4)-Dw15) did not activate T cell lines specific to SCW. However, DR4 and DR2 presented SCW to CD4+ T cells in both the high and low responders to SCW, hence the DR molecule even from the low responder haplotype functions as an restriction molecule in the low responders. Putative mechanisms linked to the association between the existence of DQ-restricted CD4+ T cells specific to SCW, and low responsiveness to SCW are discussed.     

Analysis of HLA DR2&;DQ6 (DRB1*1501, DQA1*0102, DQB1*0602) Haplotypes in Iranian Patients with Multiple Sclerosis

Multiple sclerosis (MS) is prototype of inflammatory demyelinating disease of the central nervous system .The etiology of MS remains unclear, but according to current data the disease develops in genetically susceptible individuals and may require additional environmental triggers. The human leukocyte antigen (HLA) class II alleles (DRB1*1501, DQA1*0102, DQB1*0602) may have the strongest genetic effect in MS. In this study, the role of these alleles were investigated in 183 Iranian patients with multiple sclerosis and compared with 100 healthy individuals. HLA typing for DRB1*1501, DQA1*0102, DQB1*0602 was performed by polymerase chain reaction (PCR) amplification with sequence-specific primers (PCR-SSP) method. The results show that, HLA DR B1*1501 was significantly more frequent among MS patients (46% vs. 20%, PV = 0.0006) but DQA1*0102 haplotype was negatively associated with MS (30% vs. 50%, PV = 0.0049) and no significant association was found with DQB1*0602 and MS patients in comparison with control group (24% and 30%, PV = 0.43). No significant correlation was observed among these alleles with sex, type of disease; initial symptoms, expanded disability status scale (EDSS), as well as age at onset and familial MS. This study therefore indicates that there is no association of above HLA haplotypes with clinical presentation, disease duration, and disability in Iranian patients with MS which is in line with other previous studies in different ethnic groups.     

Study of the HLA class II allele polymorphism and phylogenetic analysis in Vojvodina population

The polymorphism at the HLA DRB1 and DQB1 loci in the population of Vojvodina was studied by PCR-SSP method. A total of 13 DRB1 and 5 DQB1 specificities displaying population-specific frequency distribution pattern were described. The most frequent HLA Class II alleles in Vojvodina population were: HLA-DRB1*11 (af = 0.30), −DRB1*04 (af = 0.28), −DRB1*07 (af = 0.21), −DRB1*13 and −DRB1*16 (af = 0.18), −DQB1*03 (af = 0.64), −DQB1*05 (af = 0.39) and −DQB1*02 (af = 0.35). The haplotypes with high frequencies (≥0.02) included HLA DRB1*11 DQB1*03 (0.0825), DRB1*04DQB1*03 (0.0725), DRB1*07DQB1*02 (0.0475). The allele DRB1*07 showed the strongest association with DQB1*02 (Δ = 0.0261, gC² = 4.437) and DRB1*13 allele with DQB1*06 (Δ = 0.0222, gC² = 4.247). The allelic frequencies and populations distance dendrogram revealed the closest relationship of Vojvodina population with Hungarians, Croat, and Greeks which can be the result of turbulent migration within this region and admixture with neighbour populations during the history.     

Visualizing human leukocyte antigen class II risk haplotypes in human systemic lupus erythematosus

Human leukocyte antigen (HLA) class I and class II alleles are implicated as genetic risk factors for many autoimmune diseases. However, the role of the HLA loci in human systemic lupus erythematosus (SLE) remains unclear. Using a dense map of polymorphic microsatellites across the HLA region in a large collection of families with SLE, we identified three distinct haplotypes that encompassed the class II region and exhibited transmission distortion. DRB1 and DQB1 typing of founders showed that the three haplotypes contained DRB1*1501/ DQB1*0602, DRB1*0801/ DQB1*0402, and DRB1*0301/DQB1*0201 alleles, respectively. By visualizing ancestral recombinants, we narrowed the disease-associated haplotypes containing DRB1*1501 and DRB1*0801 to an approximately 500-kb region. We conclude that HLA class II haplotypes containing DRB1 and DQB1 alleles are strong risk factors for human SLE.     

Frequencies of the <Emphasis Type="Italic">DRB1</Emphasis>, <Emphasis Type="Italic">DQA1</Emphasis>, <Emphasis Type="Italic">DQB1</Emphasis> and <Emphasis Type="Italic">TNFA</Emphasis> alleles in immigrant population of west Siberia

Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined.