Polymorphism of three HLA-DR3-bearing major histocompatibility complex extended haplotypes.
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Genetic Linkage↗
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Molecular genetics and polymorphism of class I HLA antigens.
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Amino Acid Sequence↗
Biochemical and structural impact of natural polymorphism in the HLA-A3 superfamily.
Class I alleles of the HLA-A3 superfamily (-A*0301, -A*1101, -A*3101, -A*3301, and -Aw*6801) share largely overlapping peptide repertoires. Cross-reactive T cell responses between HLA-A3-like molecule/peptide complexes have been demonstrated in vitro and during natural diseases. In spite of this immune relatedness, HLA-A3-like molecules exhibit noticeable differences in their antigen-selecting and -presenting properties. Identifying molecular and structural features responsible for these differences is important for understanding how natural polymorphism leads to functional divergence within the HLA-A3 superfamily. Towards this goal, we used an approach that combines thermal stability data on recombinant, soluble HLA-A3-like molecules complexed with a nonamer and decamer HIV-1 peptide, together with a detailed structural analysis of these HLA-A3-like molecule/peptide complexes based on crystal and molecular model structures. Our studies revealed the importance of residues 9 and 67 for modulating peptide selection within the B pocket; of residue 97 for modulating peptide selection within the F pocket interdependently with the presence (or absence) of a middle, secondary anchor residue; and of residues 70, 73, 97, 152, and 156 for modulating peptide presentation in the central region of the groove that leads to altered antigenic surfaces. Overall, our detailed assessment of the biochemical and structural impact of natural polymorphism within the HLA-A3 superfamily has permitted to understand how HLA-A3-like molecules differ at the level of their primary and secondary anchor pockets causing fine differences in their peptide-selecting and -presenting properties. A better understanding of the molecular immunological properties of HLA-A3-like molecules is significantly important for the rationale design of broad peptide-based vaccines.
Alleles↗
HLA class II gene polymorphisms in antiphospholipid syndrome: haplotype analysis in 83 Caucasoid patients.
OBJECTIVES: We investigated the association between HLA class II haplotypes and antiphospholipid syndrome (APS). METHODS: HLA DRB1, DQB1 and DQA1 genotypes were determined by the polymerase chain reaction using sequence-specific primers in 83 Caucasoid British patients with APS. The genotype frequencies were compared between subgroups of patients and 177 healthy controls. RESULTS: DQB1*0604/5/6/7/9-DQA1*0102-DRB1*1302 and DQB1*0303-DQA1*0201-DRB1*0701 haplotypes showed significantly positive correlations with APS [P=0.0087 and P=0.0012, respectively]. The association of the former was enhanced in primary APS patients with anti-beta 2-glycoprotein I antibodies (anti-beta 2GPI) [odds ratio 6.2, 95% confidence interval (2.2-17.6), P=0.0014, corrected P=0.042]. CONCLUSIONS: These alleles and haplotypes might affect anti-ss2GPI production and APS development in different and heterogeneous fashion.
Adolescent↗
Association of the maternal 14-bp insertion polymorphism in the HLA-G gene in women with recurrent spontaneous abortions.
Human leukocyte antigen (HLA)-G has been postulated as an important immunotolerant molecule in maintaining fetal-maternal relationship. Recent reports indicated that the 14-bp deletion/insertion polymorphism in exon 8 of HLA-G gene influences HLA-G mRNA stability and isoform splicing patterns, thus modulating the levels of HLA-G expression. This might play an immunomodulatory role of HLA-G during implantation and pregnancy. In the present study, 109 unrelated fertile control women and 79 women who had experienced recurrent spontaneous abortion (RSA) were genotyped for the 14-bp insertion/deletion polymorphism. No significant difference was observed in the distribution of 14-bp insertion/deletion genotype between controls and the RSA group. However, a greater number of 14-bp insertion alleles exist in the RSA group than in the controls.
Abortion, Habitual↗
Differential expression of HLA-DRB genes according to the polymorphism of their regulatory region.
The polymorphism of the HLA-class II molecules is directly involved in the specificity of the antigen presentation. We have previously described an allelic polymorphism in the proximal promoter region of the HLA-DRB genes. In this study, we demonstrate that this polymorphism has functional consequences on the transcriptional activity of the promoter of the different DRB genes. Indeed, transiently transfected DRB gene promoters into human B cell lines showed a marked difference in their ability to induce transcription of the chloramphenicol acetyl transferase (CAT) reporter gene. These findings suggest the presence of two interdependent effects of the HLA-class II molecules on the specificity of the immune response: one corresponding to the allelic polymorphism of the peptide-binding site and the second resulting from the polymorphism of the promoter regions inducing a variable expression of the DRB genes.
DNA↗
The HLA-DOB gene displays limited polymorphism with only one amino acid substitution.
The HLA-DO molecule is a non-classical class II heterodimer composed of alpha and beta chains. We have previously recognized that all eight of the allelic variations of the HLA-DOA gene represent non-synonymous amino acid substitution. In the present study, to analyze genetic polymorphism and allelic variation of the HLA-DOB gene which may affect the efficiency of class II restricted antigen presentation thereby being involved in the susceptibility of HLA associated diseases, we conducted direct DNA sequencing of HLA-DOB in 36 HLA class II homozygous typing cells and identified six new allelic variations (DOB*0101101, *0101102, *01012, *01022, *0104101 and *0104102) including five single nucleotide polymorphisms with only one amino acid substitution. Furthermore, strong linkage disequilibrium was detected between DOB*01022 and DRB1*1502 only, with no linkage disequilibrium between the DOA and the DOB genes. The HLA-DOB gene has been identified in other mammals, and their nucleotide sequences are well conserved. These facts suggest that limited polymorphism in the DOB gene is profitable to execute their unique function as a co chaperone and so strong selective pressure is operating to prevent generic variation against the DOB molecule interacting with the DM molecule and thus maintaining the specified immunological function of regulating antigen presentation.
Alleles↗
Molecular analysis of HLA DRB1 and DQB1 polymorphism in Italian melanoma patients.
Several studies have reported association between a variety of malignancies and human leukocyte antigens (HLA) genes. However, conflicting data have been reported on HLA association and melanoma. We report here serologic and molecular analysis by polymerase chain reaction sequence-specific primers (PCR-SSP) and PCR sequence-specific oligonucleotides (PCR-SSO) of HLA class II DRB1 and DQB1 loci in 132 patients with melanoma and 102 ethnically matched controls. Molecular typing of DQB1 polymorphism showed a significant increase of DQB1 *0501 (25.0% versus 14.7%; p = 0.038). Moreover, an increase of DQB1*0301, which was present in 62.8% of patients and 54.9% of controls (p = 0.136), was noted. Because DQB1*0501 and DQB1*0301 are strongly linked to DRB1*01 and DRB1*11, respectively, both found increased in patients with melanoma, to look for a more stringent association with a particular allele specificity of the DR locus, we performed PCR-SSP high-resolution typing of DR1 and DR11 positive subjects. Results showed no significant difference between the frequencies of the alleles found in patients with respect to controls. Analysis of the distribution of DQB1*0501 and DQB1*0301 according to the AJCC clinical stage of the disease showed no significant difference in the frequency of these alleles between the localized and the metastatic form of the disease. However, none of the HLA class II alleles showed significant association after correction of the p value. These results indicate that HLA class II alleles may not contribute to a strong susceptibility to melanoma, at least in Italian patients.
Alleles↗
HLA-DRB1 and DQB1 polymorphisms in southern France and genetic relationships with other Mediterranean populations.
This study presents the results of HLA-DRB1 and DQB1 sequence-specific oligonucleotide probe (SSOP) typing for a population sample of 181 individuals originating from southern France. On the basis of allele and haplotype frequencies, we compared our population with others from the Mediterranean area. Allele frequencies are comparable to those found in other western European populations (France, Portugal, Spain) and indicate neighboring exchanges. The haplotype frequencies showed relationships with North Africans and Jewish populations, as well as the common origin of Moroccan and Lebanese Jews. Therefore, allele frequencies seem to be more able to show recent exchanges while haplotype frequencies might show ancestral relationships. These results may serve as references for future studies of HLA and disease in southern France.
Alleles↗
The nature of polymorphism of the HLA-DRB intron sequences is lineage specific.
The sequence database of HLA-DRB genes is mainly derived from mRNA analysis or has focused exclusively on the polymorphism of the 2nd exon. Little is known about the non-coding sequences of the different DRB alleles which represent about 94% of the genes. In this study we have determined the sequence of the 3' 500 bp intron 1 fragment adjacent to exon 2 in all serologically defined HLA-DRB genes and their most frequent allelic subtypes. The intron sequences turned out to be highly polymorphic. Similar to the class I introns, this variability was not characterized by random point mutations but by a highly systematic diversity reflecting the lineage-specific relationship of the HLA-DR alleles. With a few exceptions in DRBI*15, 13 and 08 as well as DRB4 and 5, the variability mirrors the serological diversity. As well as delivering insight into the genetic relationship between the different DRB alleles, these sequences will provide an extremely valuable basis for developing advanced DRB sequencing strategies for clinical purposes.
B-Lymphocytes↗
Human cytotoxic T cell responses to trinitrophenyl hapten and influenza virus. Diversity of restriction antigens and specificity of HLA-linked genetic regulation.
This report compares both the HLA restriction patterns and Ir gene regulation of human in vitro T cell-mediated cytotoxic responses to the trinitrophenyl (TNP) hapten and the type A and B influenza viruses. Comparison of the restriction patterns of these cytotoxic responses indicates that A/HK and B/HK are recognized in conjunction with polymorphic HLA-A and -B self determinants, whereas TNP is recognized in association with a more complex spectrum of self determinants. These self determinants include polymorphic HLA-A and -B determinants, polymorphic non-HLA-A and -B determinants that probably include DR antigens, and non-polymorphic determinants that appear to be species specific. Analysis of the self determinants recognized by human T cells in conjunction with influenza virus demonstrates that (a) the antigens recognized by virus-immune T cells can be distinguished from the serologically defined HLA-A and -B antigenic determinants, and (b) there may be multiple self determinants on individual HLA-A molecules that T cells can recognize in conjunction with virus. The results of family studies indicate that donors' T cells often preferentially respond to virus (and to a lesser extent TNP) in conjunction with products of one parental HLA haplotype (haplotype preference). In the family study, three HLA-identical siblings preferentially recognize paternal HLA antigens in conjunction with A/HK, and maternal HLA antigens in conjunction with B/HK and TNP, which indicates antigen-specific HLA-lined genetic control. Population studies demonstrate virus-specific differences in the ability of donors to respond to selected self HLA-A and -B antigens in conjunction with virus. These differences may be controlled by Ir genes that are distinct from HLA-A and -B, because differences are observed in the response patterns of HLA-A- and -B-matched individuals.
Antigens, Viral↗
Restriction fragment length polymorphism analysis of HLA-DR, DQ, DP and C4 alleles in Caucasians with systemic lupus erythematosus.
HLA-DR, DQ, DP and C4 null alleles were determined by restriction fragment length polymorphism (RFLP) analysis in 60 Caucasian patients with systemic lupus erythematosus (SLE) and 66 controls. DR3 (DRw17) and DQw2.1 were increased in frequency in the patients with SLE associated with the presence of C4A null genes. HLA-DP alleles determined by RFLP analysis of genomic DNA as well as of PCR amplified DNA were not associated with SLE or any clinical or autoantibody subset thereof. No DR, DQ, or C4 null gene association was found with renal or neuropsychiatric involvement or nDNA antibodies (or levels thereof). These data suggest that the primary predisposition to SLE lies with HLA-DR or C4 null alleles, and not with HLA-DP.
Alleles↗
HLA-DR and DQB1 gene polymorphism in the North-western Colombian population.
HLA-DRB1, DRB3, DRB4, DRB5 and DQB1 polymorphisms were studied using molecular methods in a population of 100 unrelated healthy individuals from an area in north-west Colombia (Medellin) inhabited by the "Paisa", a community with features of a genetically isolated group. The most frequently observed specificities at the DRB1 locus were *07 (16.4%) and *15 (12%), and at the DQB1 locus *02 (18.8%) and *03 (33.6%), of which *0302 was the most prevalent allele (14.3%). The most polymorphic specificities were DRB1*04, 13 and 11, and DQB1*06. Both the HLA-DRB1 and DQB1 loci were in linkage disequilibrium. Haplotypes were estimated using maximum likelihood methods. The most frequent two locus haplotype was DRB1*07-DQB1*02 (6.6%) and these specificities were in linkage disequilibrium. Several unusual possible haplotypes were observed. Both the HLA-DRB1 and DQB1 locus were in Hardy-Weinberg equilibrium.
Colombia↗
Restriction fragment length polymorphism analysis in the HLA class III genes of patients with diffuse panbronchiolitis.
Although diffuse panbronchiolitis (DPB) is known to be positively associated with certain major histocompatibility complex (MHC) class I antigens, e.g., HLA-B54 in Japanese patients, it is not clear whether the MHC genes predispose to the disease or are markers for other disease susceptibility gene(s). Because the HLA class III genes such as tumor necrosis factor (TNF) or the fourth component of complement (C4) are localized in the proximity of the HLA-B locus, one or more of these genes might be responsible for susceptibility to DPB. To analyze the role of HLA class III genes in DPB patients, we first evaluated the HLA-B54 association in 32 patients with DPB, and subsequently, studied the restriction fragment length polymorphism (RFLP) of the TNF-alpha and -beta (TNF-alpha/beta) genes as well as the C4A and B (C4A/B) genes in DPB patients and normal individuals. The HLA-B54 antigen was significantly more frequent in DPB patients than in normal individuals (40.3% vs 13.0%, p < 0.001), however, we did not detect a significant association between DPB and gene polymorphisms of either TNF-alpha/beta or C4A/B. Furthermore, there was no evidence of C4A gene deletion in patients with DPB. These results suggest that the HLA-B54 antigen itself might be directly involved in the pathogenesis of DPB.
Bronchiolitis↗
Functional polymorphism of the HLA-DR beta III chain.
Several clusters of class II HLA genes contribute to variation in human antigen-presenting capacity. In the HLA-DR cluster, most of the variation is due to the highly polymorphic DR beta I gene. Recent work by others has shown some nucleotide and implied amino acid sequence variation in DR beta III chains, but this variation is not known to be functionally significant. We show here that two proliferating human T-cell clones define three allelic variants of DR beta III (assignment to DR beta III based on blocking of proliferation by selected monoclonal antibodies). Thus, the DR beta III locus encodes at least three alleles that are distinguishable by human T cells and most probably contribute to the human antigen-presenting repertoire. The three DR beta III alleles subdivide the "supertypic" HLA antigen DRw52 into subtypes provisionally called DRw52.1-52.3. The DR3 haplotypes studied to date have been either DRw52.1 or 52.2; DR5 haplotypes have all (23 of 23) been 52.2; DRw6 haplotypes have included all three DRw52 subtypes, nearly half being 52.3. Our data, combined with other published data, imply that DRw8 must either have a fourth DRw52 subtype or be DR beta III null.
Alleles↗
HLA and cytokine gene polymorphisms in relation to occurrence of palindromic rheumatism and its progression to rheumatoid arthritis.
OBJECTIVE: Palindromic rheumatism (PR) is an episodic arthropathy that may precede typical rheumatoid arthritis (RA), although pathogenetic relationships between these disorders remain unclear. The predictive value for those immunogenetic risk factors implicated in RA for disease progression in PR remains to be established. A previous retrospective analysis from our group has implicated rheumatoid factor in disease progression. Our objective was to determine the contribution of HLA and cytokine gene polymorphisms implicated in RA to predisposition to PR and to progression of PR to chronic joint inflammation. METHODS: We studied 147 patients with PR seen in a tertiary referral center; 87 were selected retrospectively from the period 1986-96 using a structured selection process and 60 were selected prospectively in the period 1997-2001. Comparison groups included 149 patients with RA and 149 ethnically matched controls. Typing for HLA-DRB1 alleles and HLA-DRB1-04 subtypes was performed following polymerase chain reaction (PCR) amplification using sequence-specific primers (SSP). Cytokine genotypes were ascertained following PCR-SSP with and without digestion with restriction enzymes. Time-adjusted survival analysis (Kaplan-Meier) and multivariate logistic regression were used to assess the independent contribution of immunogenetic markers in assessing progression of PR to chronic joint inflammation. RESULTS: Thirty-one percent of patients progressed to connective tissue disease after a mean of 10.6 (retrospective group) and 3.9 (prospective group) years. A significantly increased prevalence of the shared epitope (SE) allele was noted in patients with PR (65%) versus controls (39%) (OR 2.9, 95% CI 1.8-4.6, p < 0.001). This primarily reflected increased prevalence of the DRB1-0401 and 0404 and not DRB1-01 alleles. A weak contribution to disease susceptibility was also noted with carriage of the IL4 promoter -590T (OR 1.8, 95% CI 1.1-3.0, p = 0.02) and IL4 intron 3 RP1 (OR 1.7, 95% CI 1.1-2.9, p = 0.03) alleles. The TNFa +489A allele was associated with RA (OR = 2.7, 95% CI 1.5-5.1, p = 0.001) in both SE+ and SE- patients, but not with PR. Time-adjusted and multivariate Cox regression analysis revealed that only homozygosity for SE alleles was a significant independent risk factor for disease progression to chronicity in PR (hazard ratio 2.9, 95% CI 1.2-6.9, p = 0.02). However, none of 8 patients homozygous for SE- DRB1 XP4n alleles developed chronic disease after 10 years of followup (p = 0.07). CONCLUSION: The immunogenetic risk profile for PR resembles that for RA, indicating that PR is likely not an independent entity. A significant gene dose effect for SE alleles is operative in determining risk for progression from PR to RA.
Adult↗
Structure, sequence and polymorphism in the HLA-D region.
Molecular analysis of the HLA-D region has uncovered a complex array of related genes encompassing a minimum of 6 alpha and 7 beta chain sequences. A high level of polymorphism is characteristic of the DQ alpha and beta genes, as well as DR beta. The DP genes, both alpha and beta, are also polymorphic, though to a lesser extent. The genes fit into the previously established loci: DP, DQ and DR, except for a newly-discovered sequence, DZ alpha, which is approximately equally related to all of the other alpha chain genes. Analysis of the polymorphism and evolution of the HLA-D region, by examination of the sequences, calls for several independent duplication events in the generation of this family of genes.
Base Sequence↗
HLA-G in human reproduction: aspects of genetics, function and pregnancy complications.
The non-classical human leukocyte antigen (HLA) class Ib genes, HLA-E, -G and -F, are located on chromosome 6 in the human major histocompatibility complex (MHC). HLA class Ib antigens resemble the HLA class Ia antigens in many ways, but several major differences have been described. This review will, in particular, discuss HLA-G and its role in human reproduction and in the human MHC. HLA-G seems to be important in the modulation of the maternal immune system during pregnancy and thereby the maternal acceptance of the semiallogenic fetus. Recent findings regarding aspects of HLA-G polymorphism, the possible significance of this polymorphism in respect to HLA-G function and certain complications of pregnancy (such as pre-eclampsia and recurrent spontaneous abortions (RSA)) are discussed together with possible importance to IVF. Finally, aspects of a possible role of HLA-G in organ transplantation and in inflammatory or autoimmune disease, and of HLA-G in an evolutionary context, are also briefly examined.
Female↗