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PubMed1992

HLA-DP region gene polymorphism in primary IgA nephropathy: no association.

Many features suggest that a genetically mediated abnormality of the IgA immune response is central in the pathogenesis of IgA nephropathy (IgAN). Candidate disease susceptibility genes include those encoding the MHC class II antigens, HLA-DR, -DQ, and -DP, and we have recently described an HLA-DQB1 association in IgAN. Polymorphisms of the HLA-DP region loci have been shown to associate with autoimmune diseases which share immunological features with IgAN; coeliac disease (CD) and dermatitis herpetiformis (DH). We have therefore examined restriction fragment length polymorphisms (RFLPs) of the DP alpha and DP beta chain genes (DPA1 and DPB1 respectively) in IgAN, and have studied three caucasoid populations (North, Mid, Southern Europe) to determine whether ethnic variation in genetic susceptibility exists. DNA was extracted from blood (IgAN, UK n = 89, Italy n = 75, Finland n = 49; Controls, UK n = 99, Italy n = 54, Finland n = 45), and studied by Southern blot hybridization techniques using the restriction enzymes BgI II and Msp I and cDNA 32P-labelled DPA1 and DPB1 probes respectively. The frequency distribution of the DPA1 and DPB1 fragments was similar between the three caucasoid IgAN patient groups compared to their respective controls. There was no association of DPA1 or DPB1 RFLPs with clinical features. These results suggest that HLA-DP region genes are not important in conferring disease susceptibility to IgAN and do not influence clinical disease expression. Moreover, different immunogenetic mechanisms operate in IgAN, CD, and DH.

Glomerulonephritis, IGA↗
PubMed2005

[HLA class I and II polymorphism and haplotypes in Guangdong Han population].

OBJECTIVE: To analyze the polymorphism and haplotypes of HLA class I and II in Guangdong Han population and detect the HLA-A, B, Cw and DRB1 allele frequencies. METHODS: An auto semi-quantitative PCR-sequence speacific oligonucleotide probe(PCR-SSOP) method was adopted in exploring the HLA-A, B, Cw and DRB1 genotypes of the samples from 160 bone marrow donors. RESULTS: Twelve HLA-A, 23 B, 11 Cw and 13 DRB1 alleles were obtained. A total of 9 HLA-A-B, 20 Cw-B, 7 A-Cw, and 8 A-DRB1, 9 B-DRB1, 10 Cw-DRB1 haplotypes were found. CONCLUSION: HLA class I and II alleles in Guangdong Han population have plenty of polymorphisms. The haplotype distribution possesses territory characteristic.

Asian People↗
PubMed1988

Specific restriction fragment length polymorphism on the HLA-C region and susceptibility to psoriasis vulgaris.

In psoriasis vulgaris, the HLA class I Cw6 specificity has previously been recognized as the most commonly associated antigen serologically. This study was carried out to investigate whether or not the gene controlling the susceptibility to psoriasis vulgaris existed on the HLA, especially the HLA-C region. At first, we analyzed the restriction fragment length polymorphism (RFLP) of 13 patients with psoriasis vulgaris and 6 healthy controls who were all positive for at least one allele of HLA-Cw6. To characterize RFLP in psoriasis patients who did not have HLA-Cw6, 12 patients and 10 healthy controls who had HLA-Cw7 were also examined. Southern hybridization of genomic DNA demonstrated that DNA polymorphisms of the HLA-C antigen gene could not be found in any psoriasis vulgaris patient whether HLA-Cw6 or Cw7. However, a 4.5 kb BamHI fragment and a 3.1 kb PstI fragment were lacking in some healthy controls who had either HLA-Cw6 or Cw7. This study suggests that the presence of RFLP in the HLA-C gene is associated with psoriasis vulgaris. These specific fragments may help predispose individuals to psoriasis vulgaris, or may be essential for the development of the disease.

DNA↗
PubMed1990

HLA-DR antigens and HLA-DQ beta chain polymorphism in susceptibility to rheumatoid arthritis.

Forty four patients with rheumatoid arthritis (RA) were studied for HLA-DR antigens and for HLA-DQ beta chain gene restriction fragment length polymorphism using DNA hybridisation. A significant increase in the prevalence of the DR4 antigen and a tendency towards an increase of DR1 was found in patients with RA. No allelic form of HLA-DQ restriction fragment length polymorphism patterns was increased, but the prevalence of an allele characterised by a combination of 7.5 and 3 kb fragments was decreased among patients with RA. The DQw8 subtype represented by a 12 kb fragment was the most common DR4 associated allele, and a 3.7 kb fragment related to DQw7 was found in only 5/25 (20%) DR4 positive patients and 2/12 (17%) controls. The results support the hypothesis that RA susceptibility factors are primarily located within HLA-DR genes but HLA-DQ genes may have a role in protection from the disease.

Arthritis, Rheumatoid↗
PubMed2005

Beyond the HLA typing age: genetic polymorphisms predicting transplant outcome.

Although histocompatibility testing and matching for histocompatibility leukocyte antigens (HLA) remains the "state of the art" for determining donor selection, non-HLA encoded genes such as those for minor histocompatibiity antigens also play an important role in determining haematopoietic stem cell transplantation (HSCT) outcome. Single nucleotide polymorphisms (SNPs) within the promoter regulatory regions of non-HLA encoded genes such as those for cytokines and cytokine receptors which regulate the production of such molecules may also play a role in determining the extent of post-transplant complications. Mannose binding lectin genes (MBL) and other genes such as those for myeloperoxidase (MPO) and Fcgamma receptor may aid in the control of infection post transplant. This review will summarise the latest research concerning this area of predicting HSCT outcome and indicate the potential clinical use of the results.

Graft Survival↗
PubMed2001

HLA-DPA1 and DPB1 polymorphism in four Pacific Islands populations determined by sequencing based typing.

Class II HLA-DP antigens are heterodimers comprised of alpha and beta chains coded by HLA-DPA1 and HLA-DPB1 genes. Both genes are polymorphic with substantial variation between different populations world wide. This work describes DPA1 and DPB1 polymorphism in four Pacific Island populations of Cook Islands, Samoa, Tokelau and Tonga, living in New Zealand. Using sequencing based typing four DPA1 alleles and twelve DPB1 alleles were observed in total among the four populations. There are two predominant DPA1 alleles DPA1*01031 and DPA1*02022 and three predominant DPB1 alleles DPB1*02012, DPB1*0401 and DPB1*0501. Fourteen DPA1-DPB1 haplotypes in total are present in these four populations with three predominant haplotypes: DPA1*02022-DPB1*0501, DPA1*01031-DPB1*02012, and DPA1*01031-DPB1*0401. Strong positive and negative disequilibrium was observed for individual DPA1-DPB1 haplotypes. Significant differences in DPA1 and DPB1 allele and haplotype frequencies were observed between Tokelauan and other three populations. Phylogenetic analysis of genetic distances between the four Pacific Island populations and other Asian Oceanian populations have shown that Cook Islanders, Samoans and Tongans are more closely related to Asian populations whereas Tokelauans cluster towards non-Austronesian populations of Papua New Guinea Highlanders and Australian Aborigines.

Algorithms↗
PubMed1999

Limited polymorphism in the HLA-DOA gene.

The HLA-DO molecule, a heterodimer consisting of two novel members of the class II gene family, DOA and DOB, has recently been suggested to function as an important modulator in the HLA class II restricted antigen presentation pathway by interaction with the HLA-DM molecule. In this study, we have analyzed genetic polymorphism and allelic variation of the HLA-DOA gene in 37 HLA class II homozygous typing cells using the direct DNA sequencing technique. As a result, we recognized at least eight allelic variations, DOA*01011, *0101201, *0101202, *0101203, *01013, *0101401, *0101402 and *01015. None of them, however, result in amino acid substitution. The HLA-DOA gene has been identified in other mammals as well, and the nucleotide sequences were well conserved among these species. These results suggest that the DOA molecule has undergone strong selective pressure to preserve functional structure and conformation required for interaction with the DM molecule, preventing non-synonymous amino acid substitution.

Alleles↗
PubMed2002

Pyrosequence-based typing of alleles of the HLA-DQB1 gene.

DNA typing of alleles of the highly polymorphic HLA-DQBI gene was performed by Pyrosequencing using purified DNA from the 11th International Histocompatibility Workshop human cell lines and samples from the Children's Hospital of Pittsburgh registry of diabetics and their first-degree relatives. Pyrosequencing was optimized for genotyping exon 2 of the HLA-DQB1 gene, but the procedure should be applicable to other HLA loci. The 47 HLA-DQB1 alleles were readily identifiable, as were the 1,128 potential allelic heterozygous combinations. The method required PCR conditions that specifically amplified DQB1 but not the pseudogene, DQB2. The new method of pyrosequence-based typing can be performed in 96- or 384-well format. The 61 polymorphic residues of DQB1 exon 2 were identified within four pyrosequencing reactions, obtained by a 70-nucleotide read length in each reaction, in about an hour's time. Allelic combinations of HLA-DQB1 most frequentlyfound in the population of diabetics and their immediate family members were analyzed and successfully compared to typing of the DQB1 alleles by sequence-specific oligonucleotide probe protocols. Pyrosequence-based typing is compatible with genotyping of allelic combinations expected from heterozygous individuals, resulting in nucleotide resolution of the highly polymorphic HLA system. Using pyrosequencing, more than 750 sample wells can be processed in a working day, resulting in the identification of more than 50,000 bases.

Alleles↗
PubMed1986

[Analysis of HLA-DQWa antigen ethnic polymorphism among a Japanese and Caucasian population and an association with Harada's disease].

A novel HLA-DQ antigen, DQWa was analysed with its serological, immunochemical, and molecular biological polymorphism. Furthermore, A disease association with DQWa was analysed by investigating HLA antigen frequencies of 24 patients with Harada's disease. DQWa was in linkage disequilibrium mainly with DR4-Dw15 in Japanese, and with DRw8 -Dw8 in Caucasians. The former haplotype was observed only in Japanese. A significant increase of DQWa was observed in the patients with Harada's disease (73.9% compared with 35.9% of the control, chi 2 = 9.77, P less than 0.005, Pc less than 0.05, Relative risk = 5.17). DQWa antigen molecules were different from each other between Japanese and in Caucasians, when they were analysed immunochemically by two dimensional electrophoresis, or molecular biologically by restriction fragment length polymorphism analysis. These results suggest that HLA-DQWa antigen may play a role in the pathogenesis of Harada's disease, which is seen only in Japanese.

Asian People↗
PubMed1990

HLA DQ region gene polymorphism associated with primary IgA nephropathy.

IgA nephropathy (IgAN) has been associated with HLA-DR4. We have recently described two non-allelic Taq I DQ beta gene-associated fragments sized 2.0 kb (T2) and 6.0 kb (T6), which strongly associate with DR4. T2 represents a polymorphism of the DQ beta gene and has been redesignated DQw8 (10th International HLA Workshop). The origin of the T6 fragment has not been determined, but probably represents a polymorphism of either the DQ beta or DX beta gene. When present together T2 and T6 define a subgroup of DR4 subjects at high risk of developing autoimmune disease. We have, therefore, studied DQ beta gene polymorphisms in IgAN. The DR antigen distribution was similar in IgAN and normal controls. The T2+/T6+ phenotype was present in 49% patients with IgAN compared to 15% of controls [P less than 0.0001, chi 2 = 32.8, Cramer's V = 0.41; relative risk = 5.5 (range, 2.8-11.0)]. Seventy-two percent of DR4+ IgAN patients and 29% of DR4+ controls were T2+/T6+ (P = 0.007, chi 2 = 17.0). These findings confirm the hypothesis that disease susceptibility genes are important in IgAN, and suggest that the putative gene(s) are located within or near to the DQ subregion. Moreover, similar DQ beta gene associations have been found in IDDM and pemphigus vulgaris, pointing to a common immunogenetic mechanism predisposing to several autoimmune diseases.

Blotting, Southern↗
PubMed1993

HLA class I, II, and III polymorphism in Italian patients with sarcoidosis. The Pavia-Padova Sarcoidosis Study Group.

We studied the HLA polymorphisms (class I, II, and III) in 107 Italian patients with biopsy specimen-proven sarcoidosis in order to investigate the immunogenetic background of this disease. The mean age of onset of the disease was 36.08 +/- 12.4 years. Four patients (3.73 percent) were in radiologic stage 0, 38 patients (35.51 percent) were in radiologic stage I, 40 patients (37.38 percent) were in stage II, and 25 (23.36 percent) were in stage III. Thirty-eight patients (35.51 percent) had one or more extrapulmonary localization(s) of the disease. Positive association between sarcoidosis and HLA-B8 (chi 2 = 6.07, p = 0.0127, RR = 1.91) was confirmed. Regarding the age of onset of the disease, HLA-B35 was more frequent (chi 2 = 7.34, p = 0.0056, pc < 0.05, RR = 4.62) in patients with early onset of symptoms and/or signs, before the mean age of 36 years. With reference to the radiologic stage of the disease, HLA class II marker DR3 was more frequent in patients with stage I (chi 2 = 7.22, p = 0.0061, pc < 0.05, RR = 7.08). No significant relationship was found between sarcoidosis and HLA class III markers. These results seem to confirm an association of sarcoidosis with HLA classic genes and can sustain the hypothesis of a genetic heterogeneity of this disease.

Adult↗
PubMed1994

Structural and functional analysis of HLA-DR beta-promoter polymorphism and isomorphism.

Evolutionary relatedness among the highly polymorphic DR beta genes has been established based on shared nucleotide sequences and structural organization of DR beta loci. The evolution of promoter regions of the B1*0701, B1*0101, B1*1501, B5*0101 genes was analyzed by cloning and sequencing. This shows that the polymorphism and isomorphism of HLA DR beta genes extend into the 5' flanking promoter region of the genes and that evolutionary relatedness also exists among the DR beta gene promoters. This suggests that DR beta gene promoters and coding regions coevolved. The effect of the naturally occurring nucleotide substitutions in the polymorphic and isomorphic DR beta promoters on transcriptional activity has been determined in a transient expression system. The transcriptional activity of two polymorphic DR beta promoters, B1*1501 and B1*0701, and two isomorphic DR2 promoters, B1*1501 and B5*0101, is the same for these promoters. Together these data suggest that naturally occurring substitutions do not significantly affect the transcriptional activity of these promoters.

Amino Acid Sequence↗
PubMed2000

HLA haplotypes are associated with differential susceptibility to Trypanosoma cruzi infection.

We explored a possible role of HLA class II genes in determining the susceptibility to Trypanosoma cruzi infection as well as in the development of chagasic heart disease in a rural mestizo population from Arequipa (Southern Peru). HLA-DRB1 and DQB1 polymorphisms were determined in 85 seropositive (asymptomatic, n=52; cardiomyopathic, n=33) and 87 seronegative individuals. We observed that the DRB1*14-DQB1*0301 haplotype correlates with not having T. cruzi infection in a highly endemic area (OR= 0.26 (0.124.63); Pc=0.01). This protective association is a dominant trait. We found no differences in the allelic or haplotypic distributions we examined between asymptomatic and cardiomyopathic patients in this population. Our data offer indirect but compelling evidence that polymorphism in HLA region is involved in a differential susceptibility to T. cruzi chronic infection.

Adolescent↗
PubMed1988

Linkage of HLA-DR beta specific restriction fragment length polymorphisms with Graves' disease.

HLA-DR3 positive patients with Graves' disease (6 homozygotes, 7 heterozygotes, i.e. yielding 19 haplotypes) were studied by restriction fragment length polymorphism analysis using TaqI as restriction enzyme in order to look for polymorphisms in the HLA-DR3 allele of the human major histocompatibility complex. Polymorphic TaqI fragments of 11.6, 9.8 and 5.8 kb, each corresponding to HLA-DR beta sequences, were shown to differ in their prevalence in patients with Graves' disease and controls. The prevalence of DR3 polymorphisms in a total of 35 HLA-DR3-containing haplotypes was markedly different within patients with Graves' disease and Caucasian controls. Whereas a 11.6 kb fragment was rare in Graves' disease (2/19 haplotypes vs 8/16 in controls), the inverse ratio was found for a 9.8 kb fragment, with a prevalence of 17/19 and 8/16 haplotypes, respectively. A polymorphic fragment of 5.8 kb was exclusively seen in two DR3-containing haplotypes of patients with Graves' disease. Our data provide evidence that a DNA polymorphism of the HLA-DR beta genes, which is also reflected at the product level, is linked to Graves' disease.

Cell Line↗
PubMed1999

Interaction between tumor necrosis factor microsatellite polymorphisms and the HLA-DRB1 shared epitope in rheumatoid arthritis: influence on disease outcome.

OBJECTIVE: To investigate whether interactions between tumor necrosis factor (TNF) microsatellite polymorphisms and the HLA-DRB1 shared epitope (SE) are associated with disease severity in rheumatoid arthritis (RA), and to determine if such associations are the same in male and female patients. METHODS: Genotyping for the TNFa microsatellite and HLA-DRB1 was carried out on 157 RA patients with established disease (duration >5 years). Disease severity measures included radiographic damage (the Larsen method), functional assessment by the Health Assessment Questionnaire, history of joint surgery, and global appraisal of outcome by means of a visual analog scale score. The association of severity measures with TNFa microsatellite polymorphisms stratified by SE status, and the interaction between TNFa and the SE, were investigated using stratified analyses and multiple or logistic regression analyses. RESULTS: No significant associations were observed between any single TNFa microsatellite polymorphism and disease severity, although preliminary evidence for an interaction between TNFa6 and TNFa11 was obtained. In the presence of the SE, a significantly worse outcome was associated with individuals carrying TNFa6, and a significant interaction (P = 0.04-0.006) was found between these alleles for all the outcome measures examined except history of joint surgery. In the absence of the SE, the TNFa6 allele was associated with significantly better outcome scores. When examined by sex, significant associations between the TNFa6/SE haplotype and disease outcome measures were found only in females. No statistically significant interactions were found in males, although the TNFa6/SE haplotype was still associated with the worst outcome scores. CONCLUSION: The association of the SE with disease severity in RA is influenced by an interaction with the TNFa6 microsatellite polymorphism. This interaction appears to be acting predominantly in female patients, although the trend is similar in the smaller percentage of males carrying the TNFa6/SE haplotype.

Adult↗
PubMed1991

HLA-DR and -DQ gene polymorphism in West Africans is twice as extensive as in north European Caucasians: evolutionary implications.

The HLA genes are the most polymorphic coding loci known in humans. DRB-DQA-DQB gene polymorphism was investigated by Taq I restriction fragment length polymorphism analysis in more than 700 West Africans and found to be almost twice as extensive in West Africans as in North European Caucasians. This finding indicates that Africans comprise the oldest and genetically most diverse human population and supports the hypothesis of the occurrence of a population bottleneck in the emergence of the White race. As in Caucasians, less than one-third of possible cis-encoded DQA-DQB combinations were encountered, indicating constraints on the pairing of DQ alpha and beta polypeptides. Heterozygote advantage (i.e., positive selection) was found for DRB, DQA, and DQB alleles as well as for DQA-DQB combinations. However, in West Africans as well as in North Europeans the observed frequencies of DRB-DQA-DQB homozygotes were close to neutrality expectations. Although the hypothesis that HLA polymorphism is maintained by parasite-driven overdominant selection is attractive, there is little evidence to support that view. We propose instead that one of the forces maintaining a low frequency of HLA homozygotes might be a decreased likelihood of potentially autoreactive T-cell clones escaping thymic selection in HLA heterozygotes. This would be consistent with the central role of HLA molecules as self/non-self discriminators.

Africa, Western↗
PubMed1998

HLA-DRB1, -DQB1 and -DPB1 polymorphism in the Slovak population.

HLA-DRB1, -DQB1 and -DPB1 allele frequencies were investigated in a sample of the Slovak population by PCR-SSP and PCR-RFLP methods. The most frequent DRB1 alleles were DRB1*1101-5 (0.2038), DRB1*0701-2 (0.1423), and DRB1*1501-2 (0.1231). The most rare alleles found were DRB1*0901 (0.0038), and DRB1*1201 (0.015). The most common DQB1 alleles were DQB1*0301 (0.2448), DQB1*0201 (0.2098), and DQB1*0501 (0.1119), respectively. The alleles with the least occurrence rate were DQB1*0601 (0.0035) and DQB1*0401 (0.007). The most common DPB1 alleles found were DPB1*0401 (0.4329), DPB1*0402 (0.2089), and DPB1*0201 (0.1438), respectively. The least frequent alleles were DPB1*0601, *1101, and *1501 (0.0034). Allele frequencies found in our study were compared to those in Czech, Austrian, and German populations. No statistically significant differences were observed.

Alleles↗