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PubMed1990

HLA in juvenile dermatitis herpetiformis: clinical heterogeneity correlated with DNA and serological polymorphism.

A group of 30 Italian children affected by Dermatitis Herpetiformis (DH) was analysed for HLA region polymorphisms with both serological and DNA methods. Serological typing was performed on HLA-A, B, C, DR, DQ antigens and C4A, C4B, Bf polymorphisms. DNA RFLPs obtained with TaqI enzyme were investigated with cDNA probes specific for DR beta, DQ alpha and DQ beta genes. The results were correlated with intestinal involvement and age at onset of the disease. The following observations were made: (1) the intestinal biopsies revealed a direct correlation between degree of lesions and age at onset of DH; (2) a significantly increased relative risk (RR) was found for the following HLA antigens: A1 (RR = 2.2), B8 (RR = 6.2), Cw7 (RR = 3.9), C4AQ0 (RR = 7.4), DR3 (RR = 5.2), DR7 (RR = 4.4), DRw53 (RR = 4.7), DQw2 (RR = 6.0); (3) B8 and DR3 were significantly more frequent in patients with severe intestinal lesions; and (4) of the two DR3 subtypes revealed by RFLP typing, only 3.1 showed an increased frequency in DH patients (RR = 8.4). It is suggested that the susceptibility to Juvenile DH is determined by the same genes, within the HLA region, that are associated with Coeliac Disease.

Adolescent↗
PubMed2001

Cytotoxic T lymphocyte antigen 4 gene polymorphism confers susceptibility to type 1 diabetes in Japanese children: analysis of association with HLA genotypes and autoantibodies.

OBJECTIVE: Although the polymorphisms of the cytotoxic T lymphocyte antigen 4 (CTLA4) gene have been shown to be associated with Type 1 diabetes in Caucasians, some conflicting results have been reported among subjects of different ethnic backgrounds. We examined a CTLA4 polymorphism and its relationship to human leucocyte antigen (HLA) genotypes and autoantibodies for glutamic acid decarboxylase 65 (GAD65) and IA-2 in Japanese children with Type 1 diabetes. SUBJECTS AND MEASUREMENTS: The study group consisted of 125 childhood-onset Japanese subjects (50 males, 75 females) with Type 1 diabetes. The CTLA4 A/G polymorphism at position 49 was analysed using a PCR-restriction fragment length polymorphism (PCR-RFLP) method. The HLA-DRB1 and DQB1 genotypes were defined by DNA analysis using PCR-sequence-specific oligonucleotide (PCR-SSO) probes. The GAD65 autoantibody (GAD65Ab) and IA-2 autoantibody (IA-2Ab) titres were measured using radioimmunoassay. RESULTS: The distribution of genotype frequencies differs between subjects with Type 1 diabetes (GG: 46%, AG: 50%, AA: 5%) and controls (GG: 39%, AG: 44%, AA: 17%) (P < 0.01). The frequency of the G allele is higher in the diabetes group than in the controls (P < 0.05). When the subjects were subdivided according to HLA genotype, the two major HLA high-risk groups, with DR9-DQ9 and DR4-DQ4, that are unique to Japanese populations showed no difference in their CTLA4 polymorphism frequencies. Although no association between the CTLA4 polymorphism and the prevalence of GAD65Ab was found, CTLA4 GG subjects that had been newly diagnosed (< 9 months) had significantly higher levels of autoantibodies than AG subjects (P < 0.01). The prevalence and titres of IA-2Ab were not associated with the CTLA4 polymorphism. CONCLUSIONS: The CTLA4 gene might confer a susceptibility to childhood-onset Type 1 diabetes in the Japanese population. The association between this CTLA4 polymorphism and the HLA genotype was similar for both major groups with HLA high-risk alleles. CTLA4 might contribute to the humoral immune response to GAD in newly diagnosed subjects.

Abatacept↗
PubMed2002

Infectious complications in sickle cell disease are influenced by HLA class II alleles.

Despite systematic antibiotic therapy, severe infections (septicemia, meningitis, or osteomyelitis) are a major cause of mortality and morbidity in children with sickle cell disease (SCD). In this study, we explored the possibility that polymorphism at the human leukocyte antigen (HLA) locus might constitute an immunogenetic modifying factor to the intrinsic susceptibility to infection in patients with SCD. A cohort of 80 SCD patients living in Paris, 43 with at least one major infectious complication and 37 without infections, were typed for HLA class II loci by polymerase chain reaction-sequence-specific primers (PCR-SSP). We found that significantly more patients without infections carry the HLA class II DRB1*15 specificity than did patients with infections (21.6% in the first group, versus 4.7% in the second group; chi(2) = 10.47, p(c) = 0.01), supporting a protective effect of this allele. Conversely, significantly more patients were found to carry the DQB1*03 specificity within the group of severe infections, supporting a negative effect (34.9% versus 12.2%, chi(2) = 9.41, p(c) = 0.01). These findings suggest a direct involvement of HLA polymorphism in the development of major infections in SCD. Together with previous data on polymorphism of the Fc receptor and of the mannose-binding lectin, they provide evidence for a polygenic immunomodulation of the constitutively increased infectious risk in SCD.

Adolescent↗
PubMed1985

Use of pooled DNA samples to detect linkage disequilibrium of polymorphic restriction fragments and human disease: studies of the HLA class II loci.

A rapid method has been developed and used to search for restriction fragment length polymorphisms (RFLPs) that are in linkage disequilibrium with disease-associated loci. By using genomic blot-hybridization analysis with DQ beta-chain and DR beta-chain cDNA probes, we examined DNA polymorphisms within the HLA class II loci associated with susceptibility to insulin-dependent mellitus (IDDM). To facilitate the search for informative RFLPs, we compared pooled DNA samples from IDDM patients with pooled DNA samples from randomly selected control individuals, instead of using the conventional approach of examining DNA samples from individuals in two groups. (The conditions under which this approach is useful are treated theoretically in the Appendix.) Several specific polymorphic restriction fragments associated with IDDM were revealed by using this economical and rapid approach. The restriction enzymes and probes identified as informative in this screening were then used to analyze HLA-DR-typed IDDM families, homozygous typing cells, and unrelated individuals to determine the association of the specific restriction fragments with HLA-DR serological type and the frequency in control and IDDM populations. Some individual polymorphic fragments for which the IDDM population was enriched correlated strongly with HLA-DR3, whereas others correlated strongly with HLA-DR4. Some fragments (e.g., a 10-kilobase Taq I fragment detected with the DR beta probe) that were more prevalent in the IDDM population subdivided the serologically defined HLA-DR type and may be informative markers for IDDM susceptibility.

Cloning, Molecular↗
PubMed1986

Reduced complexity of RFLP for HLA-DR typing by the use of a DR beta 3' cDNA probe.

The polymorphism of the HLA system has been defined by alloantisera, monoclonal antibodies, MLC reactivity, protein chemistry and RFLP patterns in DNA analysis. Typing for the alleles of HLA-DR at the DNA level as an additional typing technique is useful since any nucleated cell can be used. Moreover, it is not known whether the additional polymorphism found at the DNA level in an unambiguous serotype is of functional importance and thus needs to be included in HLA-DR typing. A main problem in DNA typing is the interpretation of the complex patterns in Southern blot analysis, especially in heterozygous individuals. Therefore we constructed subprobes from full length DR beta, DQ alpha and DQ beta cDNA to reduce the number of hybridizing fragments while retaining the discriminating capacity. The clearest differences among DR alleles have been found using the restriction enzyme PvuII and the subprobe containing the 3' untranslated region of the DR beta probe. Although further characterization is necessary to be able to type at the DNA level, the simplified patterns facilitate DNA typing in heterozygous individuals for a number of haplotypes. Interestingly, the number of fragments thus obtained corresponds with the number of genes described for DR1 to DRw8 haplotypes. Based upon the finding of common hybridizing patterns in DR3, DR5 and DRw6 it may be concluded that DR3, DR5 and DRw6 have been evolved from a common ancestor. For the same reason DR4, DR7 and DRw9 may have evolved in an identical way.

Cloning, Molecular↗
PubMed2001

HLA class I diversity in Kolla Amerindians.

Human leukocyte antigen (HLA) class I polymorphism was studied within a population of 70 unrelated Kolla Amerindians from the far northwest of Argentina close to the Bolivian border. The results indicate that the HLA-A, -B, and -C alleles typical of other Amerindian populations also predominate in the Kolla. These alleles belong to the following allele groups: HLA-A*02, *68, *31, *24, HLA-B*35, *15, *51, *39, *40, *48, and Cw*01, *03, *04, *07, *08, and *15. For the HLA-A locus, heterogeneity was seen for HLA-A*02 with A*0201, *0211, and *0222; and for A*68 with *68012 and *6817, the latter being a novel allele identified in this population. Analysis of HLA-B identified heterogeneity for all Amerindian allele groups except HLA-B*48, including the identification of the novel B*5113 allele. For HLA-C heterogeneity was identified within the Cw*07, *04, and *08 groups with Cw*0701/06, *0702, *04011, *0404, *0803, and *0809 identified. The most frequent "probable" haplotype found in this population was B*3505-Cw*04011. This study supports previous studies, which demonstrate increased diversity at HLA-B compared with HLA-A and -C. The polymorphism identified within the Kolla HLA-A, -B, and -C alleles supports the hypothesis that HLA evolution is subject to positive selection for diversity within the peptide binding site.

Alleles↗
PubMed2005

HLA-DRB1 allele polymorphosm associated with susceptibility to leukemia in Han nationality of Gansu.

The study was aimed to explore the possible association between HLA-DRB1 allele polymorphism and the susceptibility to leukemia in Gansu Chinese Han nationality and to find the genes susceptible to leukemia. HLA-DRB1 genes in 74 patients with leukemia from northwestern China and 82 healthy Chinese controls were determined by polymerase chain reaction and sequence-specific oligonucleotide probe hybridizations (PCR/SSO) DNA analysis. The results showed that as compared with control, the allele frequencies of HLA-DRB1*03 (chi(2) = 8.125, P = 0.004), HLA-DRB1*07 (chi(2) = 13.526, P = 0.000), HLA-DRB1*08 (chi(2) = 18.855, P = 0.000), HLA-DRB1*13 (chi(2) = 7.039, P = 0.008) significantly increased in AML group. The allele frequencies of HLA-DRB1*07 (chi(2) = 5.689, P = 0.017), HLA-DRB1*11 (chi(2) = 7.73, P = 0.005), HLA-DRB1*12 (chi(2) = 4.234, P = 0.040), HLA-DRB1*13 (chi(2) = 38.333, P = 0.000) significantly increased in CML group. The allele frequency of HLA-DRB1*01 (chi(2) = 5.294, P = 0.021) significantly increased in ALL group. It is concluded that the susceptibility to AML in Gansu Han nationality is positively related to HLA-DRB1*03. 1*07.1*08.1*13. CML positively correlates with HLA-DRB1*07. 1*11.1*12.1*13, and ALL may be positively in relation with HLA-DRB1*01. Allele polymorphism is associated with the leukemia occurrence.

Acute Disease↗
PubMed2001

HLA-DQB1 CAR1/CAR2, TNFa IR2/IR4 and CTLA-4 polymorphisms in Tunisian patients with rheumatoid arthritis and Sjögren's syndrome.

OBJECTIVES: To evaluate the contribution of HLA class II region and the CTLA-4 gene in genetic susceptibility to rheumatoid arthritis (RA) and Sjögren's syndrome (SS) in the Tunisian population. METHODS: The polymorphisms of a (CA)n microsatellite of HLA-DQB1 CAR1/CAR2, TNFa IR2/IR4 and an (AT)n microsatellite in the 3'-untranslated region of exon 3 of the CTLA-4 gene were analysed after specific polymerase chain reaction (PCR) amplification. Typing of CTLA-4 A/G exon 1 polymorphism was achieved by the PCR-restriction fragment length polymorphism method. RESULTS: Genomic DNA from 60 patients with RA, 58 patients with SS and 150 healthy individuals was genotyped. The distribution of HLA-DQ CAR1/CAR2 allele frequencies differed between patients and controls in both diseases (RA, P<10(-15); SS, P=7.6x10(-15); RA+SS, P<10(-15)). The analysis of TNFa IR2/IR4 and CTLA-4 A/G polymorphisms did not show any differences in allele or genotype frequencies between patients and control subjects in either disease. The distribution of CTLA-4 (AT)n allele frequencies differed between patients with RA and controls (P=10(-3)), whereas no significant difference was detected between patients with SS and controls. CONCLUSION: These data suggest the involvement of HLA-DQ CAR1/CAR2 polymorphisms in genetic susceptibility to RA and SS and the participation of the CTLA-4 gene, or a gene closely associated with it, in the development of RA.

Abatacept↗
PubMed1999

Genomic organization around the centromeric end of the HLA class I region: large-scale sequence analysis.

We previously sequenced two regions around the centromeric end of HLA class I and the boundary between class I and class III. In this paper we analyze the two regions of about 385 kb and confirm, giving a new line of evidence, that the following two pairs of the genomic segments were duplicated in evolution: (i) a 43-kb genomic segment including the HLA-B gene showing the highest polymorphism among the classical HLA class I loci (class Ia) and a 40-kb segment including the HLA-C locus showing the lowest polymorphism and (ii) a 52-kb segment including the MIC (MHC class I chain related gene) B and a 35-kb segment including MICA. We also found that repetitive elements such as SINEs, LINEs, and LTRs occupy as much as 47% of nucleotides in this 385-kb region. This unusually high content of repetitive elements indicates that repeat-mediated rearrangements have frequently occurred in the evolutionary history of the HLA class Ia region. Analysis of LINE compositions within the two pairs of duplicated segments revealed that (i) LINEs in these regions had been dispersed prior to both the duplication of the HLA-B and -C loci and the duplication of the MICB and MICA loci, and (ii) the divergence of the HLA-B and -C loci occurred prior to the duplication of the MICA and MICB loci. To find novel genes responsible for HLA class I-associated or other diseases, we performed computer analysis applying GenScan and GRAIL to GenBank's dbEST. As a result, at least five as yet uncharacterized genes were newly mapped on the HLA class I centromeric region studied. These novel genes should be analyzed further to determine their relationships to diseases associated with this region.

Base Sequence↗
PubMed1999

The central MHC gene IKBL carries a structural polymorphism that is associated with HLA-A3,B7,DR15.

Susceptibility to several disorders, including insulin-dependent diabetes mellitus and multiple sclerosis, has been associated with alleles of HLA class II genes and loci in the TNF cluster in the central major histocompatibility complex (MHC) region. As recombination within this region is rare, it is difficult to determine which genes are important. This will be facilitated by the identification of functional polymorphisms. Hence we are sequencing reverse transcription-polymerase chain reaction products derived from central MHC genes in well characterized and conserved ancestral haplotypes. Here we address the IKBL gene, which lies near the TNF cluster at the telomeric end of the central MHC. Although the IKBL cDNA sequence was conserved between most ancestral haplotypes, a synonymous nucleotide substitution, a 3' untranslated region substitution, and a single nonsynonymous substitution were identified. The latter (IKBL+738) was present in multiple examples of the 7.1 haplotype [HLA-A3, B7, DR2 (DR15)] and resulted in a cysteine to arginine substitution in a predicted protein kinase C phosphorylation site. This polymorphism did not occur in 18 other common haplotypes from the 10th International Histocompatibility Workshop and thus appears haplospecific. A role for IKBL+738 in the association between HLA-A3,B7,DR2(DR15) and susceptibility to multiple sclerosis is discussed.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Allelic polymorphism in introns 1 and 2 of the HLA-DQA1 gene.

Human leukocyte antigen (HLA) class II antigens are highly polymorphic membrane glycoproteins, encoded by the A and B genes of DR, DQ, and DP. The polymorphism is mainly located in exon 2, with the exception of DQA1. Of the 27 DQA1 alleles presently known, 18 cannot be identified on the basis of exon 2 alone, but need additional information from the other exons. DQA1 has been reported to be the most ancient class II gene. For evolutionary comparison and to assess the degree of polymorphism outside the exons, the sequences of introns 1 and 2 were determined from 30 different cell lines, encompassing 15 different DQA1 alleles. The sequences revealed major nucleotide differences between the different lineages, whereas within each lineage few differences were present. Phylogenetic analysis of intron and exon sequences confirmed this lineage specificity. Altogether, the present data indicate that the HLA-DQA1 lineages represent ancient entities. The observed variation of the introns in alleles with identical exon sequences implicates conservative selection of the exons within a given lineage. Intron sequences may provide the means to set up an accurate typing system.

Base Sequence↗
PubMed2003

[The genetic characteristic of HLA-DRB1 locus in the Jiangsu-Zhejiang-Shanghai Han population and a comparison of its frequency distribution with that of other populations].

OBJECTIVE: To investigate the genetic polymorphism of HLA-DRB1 locus in Jiangsu-Zhejiang-Shanghai Han population and analyze the characteristic of the allele frequency distribution in comparison with that of other populations. METHODS: The technique of polymerase chain reaction-sequence specific primers (PCR-SSP) and reverse polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) was adopted in genotyping a sample of 626 unrelated healthy individuals collected from a Chinese Han population in Jiangsu-Zhejiang-Shanghai area. HLA-DRB1*0101-1001, DRB3, DRB4 and DRB5 were detected. The allele frequency of HLA-DRB1 was calculated, and the allele frequency distribution of HLA-DRB1 in this population was compared with the results from other populations. RESULTS: HLA-DRB1*0101, 0301, 0701, 09012, 1001, 1201, 1202, 1301/02, 1303/04, 1401/04/05, 1402/03/1305, 1501/02, 16021 and 04xx, 08xx were detected in Jiangsu-Zhejiang-Shanghai Han population. The common HLA-DRB1*allele included 09012(17.97%), 04xx(12.53%), 1202(11.42%) and 1501/02(11.02%). The polymorphism information content is 0.9024, and expected heterozygosity is 0.9634 in Jiangsu-Zhejiang-Shanghai Han population. CONCLUSION: The HLA-DRB1 distribution of Jiangsu-Zhejiang-Shanghai Han population shares some genetic characteristic with other Han populations, but it exhibits its own characteristic, suggesting the intermediate state of this population between the southern and northern Han populations. The polymorphism of HLA-DRB1 of Jiangsu-Zhejiang-Shanghai Han population is the most abundant one in this study.

China↗
PubMed1991

Effect of natural polymorphism at residue 86 of the HLA-DR beta chain on peptide binding.

Class I and class II MHC glycoproteins are highly polymorphic molecules that bind antigenic peptides and present them on cell surfaces for recognition by T lymphocytes. Even though MHC polymorphism has long been known to affect both peptide binding and recognition by the TCR, the role of individual amino acids of MHC proteins in these interactions is poorly understood. To examine the effect of a small number of amino acid residues on T cell stimulation, B lymphoblastoid cell lines homozygous for the closely related DR1 subtypes, Dw1 and Dw20, and the DR4 subtypes, Dw4 and Dw14, were compared for their ability to present an immunogenic influenza hemagglutinin peptide (HA307-319) to an Ag-specific, DR1,4-restricted T cell clone. B cell lines expressing DR1 Dw20 and DR4 Dw14 presented HA307-319 much less efficiently than DR1 Dw1 and DR4 Dw4 and bound a biotinylated analogue of the same peptide less well. Analysis of DRB1 gene sequences suggested that polymorphism at residue 86 had a major effect on peptide binding. Differences in binding of a set of HA307-319 analogues biotinylated at each residue to cells expressing DR1 Dw1 and DR1 Dw20 suggested that the polymorphism affected the interactions of many peptide residues with the class II molecule. In inhibition assays, DR1 Dw1 and DR4 Dw4 were shown to differ from DR1 Dw20 and DR4 Dw14 in their length requirements for peptide binding. Using a larger panel of homozygous B cell lines expressing many class II haplotypes, a Ser-309 substituted HA307-319 analogue was shown to bind to most B cell lines expressing Val-86 containing alleles (including DR1 Dw20 and DR4 Dw14) but failed to bind most B cell lines expressing Gly-86 alleles (including DR1 Dw1 and DR4 Dw4). The results indicated that polymorphism at residue 86 influenced the specificity and affinity of peptide binding and affected the conformation of peptide-DR protein complexes without completely eliminating T cell recognition.

Alleles↗
PubMed1993

Classification of mutations at the HLA-A locus by use of the polymerase chain reaction.

We investigated whether the polymerase chain reaction (PCR) could be used to determine the mechanism of mutation in lymphocyte clones mutated at the HLA-A locus. Three polymorphisms, at Factor XIIIA, D6S109, and intron 3 of the HLA-A gene, were used to study a series of clones previously characterised by Southern blotting (SB) at multiple loci on chromosome 6. For detection of loss of heterozygosity, the results of PCR and SB were concordant in 140 of 141 clones when polymorphism in the Factor XIIIA region was studied and in 144 of 145 clones when polymorphism in the HLA-A gene was studied. For classification of the mechanism of mutation, PCR and SB gave the same result in 88 of 92 clones (96%) when a combination of the HLA-A and Factor XIIIA polymorphisms was used and in 46 of 47 clones (98%) when a combination of the HLA-A and D6S109 polymorphisms was used. The results indicate that PCR provides a simple and reliable method for categorising mutations at the HLA-A locus as arising from mitotic recombination, deletion, or from presumptive minor changes within the gene. Rare events such as gene conversion, nondisjunction, or large deletions extending to the telomere will be misclassified. However, such events are rare for mutations at this locus.

Base Sequence↗
PubMed1983

Analysis of human class I antigens by two-dimensional gel electrophoresis. I. Polymorphism, evidence for additional (non-HLA-A, B, C) gene products, and identification of variant HLA-A, B antigens.

Class I antigens were isolated by immunoprecipitation from cell extracts prepared from mitogenically stimulated and internally radiolabeled peripheral blood lymphocytes (PLBs). The precipitating antibodies used are monomorphic and recognize a determinant on the heavy chain of HLA-A, B, C antigens regardless of their allelic specificities when complexed with beta 2m, or determinants on beta 2m itself. Comparison of class I molecules isolated from 25 different homozygous typing cells (HTC) and analyzed by two-dimensional (2-D) gel electrophoresis allowed the identification of those HLA-A, B locus specificities most common in the European Caucasoid population. Class I antigens isolated from HTC that are HLA identical are biochemically indistinguishable also. Evidence was obtained for the expression of additional class I antigens besides the HLA-A, B, C locus products: for some haplotypes, up to six class I genes may be active in mitogenically activated PBLs.No differences in molecular weight and isoelectric point of the class I heavy chains were observed between the antigens recognized by W6/32, the anti-heavy chain reagent, and anti beta 2m reagents. The nature of the mitogenic stimulus, i.e., pokeweed mitogen or phytohemagglutinin, was irrelevant with respect to the class I antigens isolated by this method. Using the HTCs as reference, a panel of HLA-B27 positive heterozygous cells was analyzed. Two types of HLA-B27 antigens, distinct by CML typing were represented. These two forms differed also in their biochemical properties. In addition, we obtained evidence for the existence of an A2 variant. This finding was likewise confirmed by CML typing.

Electrophoresis, Agar Gel↗
PubMed2003

KIR in type 1 diabetes: disparate distribution of activating and inhibitory natural killer cell receptors in patients versus HLA-matched control subjects.

Killer cell immunoglobulin-like receptors (KIRs) modulate natural killer cell and T-cell function by interacting with HLA class 1 ligands on target cells. Both KIR and HLA are highly polymorphic. We studied the influence of KIR and HLA class 1 genes on the susceptibility to develop type 1 diabetes. The results showed increased numbers of activating KIR genes in patients compared with control subjects (P = 0.049). The combination of the activating KIR2DS2 gene, together with its putative HLA ligand, was present more frequently in patients than in diabetes high-risk HLA-matched control subjects (P = 0.030). Moreover, our results imply that an increase in activating KIR2DS2-HLA ligand pairs combined with a lack of inhibitory KIR-HLA ligand pairs is associated with an additional risk to develop type 1 diabetes in individuals with diabetes high-risk HLA alleles (P = 0.035). We propose that the genetic imbalance between KIR and their HLA class 1 ligands may enhance the activation of T-cells with a low affinity for pancreatic self-antigens, thereby contributing to the pathogenesis of type 1 diabetes.

Adolescent↗