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HLA class II (DR and DQ) antigen associations in idiopathic dilated cardiomyopathy. Validation study and meta-analysis of published HLA association studies.

We previously reported antigen frequency differences for HLA-DR4 and HLA-DRw6 between idiopathic dilated cardiomyopathy (IDC) patients and healthy controls in a pilot study. To confirm these findings, we undertook an independent study with a prospective hypothesis regarding the frequencies of DR4 and DRw6; typing for a second family of class II antigens (HLA-DQ) was included because of the proximity of the DQ loci to the DR loci and the strong linkage disequilibrium between some of the DR and DQ alleles. Comparing a new consecutive series of IDC patients (n = 41) and healthy blood bank controls (n = 53), we confirmed an increase of DR4 antigen frequency in patients (49% versus 21%, p less than 0.005). A trend toward decreased expression of DRw6 among patients was also noted (10% of patients versus 23% of controls). HLA-DQw4 was significantly elevated in patients compared with controls (27% versus 6%, p less than 0.005; relative risk, 6.1; etiologic fraction, 0.22). We identified the combined DR4-DQw4 haplotype in five of 41 Caucasian IDC patients (12%) and none of 53 controls (p less than 0.007). A comparison of specific antigen frequencies between the preliminary and validation studies did not reveal significant differences; therefore, the data from the two studies were examined in combination. For the combined studies, DR4 was elevated (51% versus 27% in controls, p less than 0.001), and DRw6 was decreased (9% versus 24% in controls, p less than 0.01). The relative risk for DR4 was 2.8, and the etiologic fraction was 0.33.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Dilated↗

Association of high HIV-1 RNA levels and homozygosity at HLA class II DRB1 in adults coinfected with Mycobacterium tuberculosis in Harare, Zimbabwe.

HIV-1 mRNA levels (virus load) were quantified for 191 pulmonary tuberculosis (TB) patients and 132 HIV-1 seropositive controls. Human leukocyte antigen (HLA) class I and II genes were typed for 188 patients and 121 HIV-1 seropositive controls. The mean log virus load was higher among cases than HIV-1 seropositive controls (p < 0.0001). Among the controls, mean log virus load was higher among males than females (p = 0.04). There was no association between virus load and homozygosity at HLA class I and II among the controls. In contrast, among the cases, HLA-DRB1 homozygosity was associated with high virus load (p = 0.008), conferring risk for rapid progression to AIDS, thus lending support to the heterozygote advantage hypothesis. The observed decreased virus load in HLA-DRB-1 heterozygotes may be due to a better control of M. tb. infection in the context of HIV-1 disease.

Acquired Immunodeficiency Syndrome↗

Association of maternal histocompatibility at class II HLA loci with maternal microchimerism in the fetus.

For investigating the possible influence of maternal-fetal HLA compatibility on maternal microchimerism, DNA samples from blood of 120 maternal-fetal pairs were genotyped at two polymorphic loci: glutathione-S-transferase M1 (GSTM1) and angiotensin-converting enzyme (ACE). Informative pairs (mother heterozygous/fetus homozygous at one of the two loci) were then tested by quantitative real-time PCR for the noninherited maternal allele(s) and genotyped at the HLA-A, B, and C class I loci and/or at the DRB1 and/or DQB1 class II loci. Small numbers of maternal cells were detected in the circulation of 16 of the 30 informative second- and third-trimester fetuses. Comparison with HLA data suggested an association between microchimerism and maternal compatibility at the class II DRB1 and/or DQB1 HLA loci and with the maternal HLA-DQB1*0301 allele. There was no relationship between maternal microchimerism and maternal-fetal HLA compatibility at other HLA loci or with gestational age, fetal anomalies, or red cell or platelet isoimmunity.

Adult↗

An HLA class II region restriction fragment length polymorphism (RFLP) in patients with dermatitis herpetiformis: association with HLA-DP phenotype.

Dermatitis herpetiformis (DH) is characterized in part by an associated gluten-sensitive enteropathy (GSE), and a strong association with the HLA antigens HLA-A1, -B8, -DR3, and -DQw2, essentially identical to that seen in patients with isolated GSE (celiac disease). A 4.0-kb RsaI RFLP has been identified using a DQ beta-chain cDNA and localized to the HLA-DP beta-chain region. This RFLP has been found more frequently in patients with isolated GSE than in normal HLA matched controls. We have analyzed genomic DNA from 24 patients with DH and 15 HLA-matched controls to determine if this 4.0-kb RsaI RFLP was present in patients with DH. Twenty-one of 24 (87%) of patients with DH were found to have this RFLP as compared to 7 of 10 (70%) HLA-DR3, -DQw2 matched control subjects (p = 0.23). Thus, the 4.0-kb RsaI RFLP detected in patients with isolated GSE is also present in patients with DH; however, its frequency in DH patients does not differ significantly from that of HLA matched controls. Family studies of patients with DH revealed that although the 4.0-kb RsaI RFLP segregated with the HLA-A1, -B8, -DR3, -DQw2 haplotype in one family, it did not segregate with this disease-associated haplotype in two other families. In both patient and control populations, this RFLP was associated with HLA-DPw1 or -DPw3 phenotypes; 25 of 26 (96%) HLA-DPw1 or -DPw3 subjects were found to have this RFLP compared to only 1 of 6 (17%) who did not express HLA-DPw1 or -DPw3 (pc = 0.0009). These population and family data suggest that this 4.0-kb RsaI RFLP is primarily associated with the HLA-DPw1, -DPw3 phenotype, rather than the clinical manifestations of DH. These data further document that the strongest association of DH with HLA antigens remains with HLA-DQw2 and HLA-DR3 antigens.

Cell Line↗

[Class II HLA antigens in patients with multiple sclerosis from Warsaw and Gdansk regions].

An investigation of class II histocompatibility antigens was carried out in patients with definite diagnosis of multiple sclerosis (MS) according to Poser's criteria. There were 42 patients from Warsaw and 98 patients from Gdańsk. Histocompatibility antigens were assayed with microlymphocytotoxicity test. 6 antigens on locus DR and 1 antigen on locus DQ were evaluated. The antigen frequencies were compared in the two groups using the chi-square test. The antigen HLA-DQw1 occurred significantly more frequently in MS patients compared to healthy control group. Antigens HLA-DR2 and DR3 occurred more frequently in patients from Gdańsk than Warsaw region.

Adult↗

Extensive HLA class II studies in 58 non-DRB1*15 (DR2) narcoleptic patients with cataplexy.

Narcolepsy is a sleep disorder that has been shown to be tightly associated with HLA DR15 (DR2). In this study, 58 non-DR15 patients with narcolepsy-cataplexy were typed at the HLA DRB1, DQA1 and DQB1 loci. Subjects included both sporadic cases and narcoleptic probands from multiplex families. Additional markers studied in the class II region were the promoters of the DQA1 and DQB1 genes, two CA repeat polymorphisms (DQCAR and DQCARII) located between the DQA1 and DQB1 genes, three CA repeat markers (G51152, T16CAR and G411624R) located between DQB1 and DQB3 and polymorphisms at the DQB2 locus. Twenty-one (36%) of these 58 non-DR15 narcoleptic patients were DQA1*0102 and DQB1*0602, a DQ1 subtype normally associated with DRB1*15 in DR2-positive narcoleptic subjects. Additional microsatellite and DQA1 promoter diversity was found in some of these non-DR15 but DQB1*0602-positive haplotypes but the known allele specific codons of DQA1*0102 and DQB1*0602 were maintained in all 21 cases. The 37 non-DQA1*0102/DQB1*0602 subjects did not share any particular HLA DR or DQ alleles. We conclude that HLA DQA1*0102 and DQB1*0602 are the most likely primary candidate susceptibility genes for narcolepsy in the HLA class II region.

Cataplexy↗

Frequency and associations of HLA class II TaqI allogenotypes in the Northern Ireland population.

HLA-DR allogenotyping was performed on a panel of 1019 Caucasian individuals from the Northern Ireland population, of whom 150 were also HLA-DQ allogenotyped, using a single enzyme (TaqI)/multiple probe system. TaqI/DR beta restriction fragment length polymorphisms correlate well with the serologically defined specificities and in addition detect further subtypes of these associated with DQ or Dw specificities. The most frequent DR beta allogenotypes were DR beta 15, DR beta 4, and DR beta 17 (Dw24). The frequency of the subtypes of DR beta 4 associated with DQ beta 3 (TA10+) was higher than that reported elsewhere for Caucasian populations, whereas the frequency of the subtypes of DR4 beta associated with DQ beta 3(TA10-) was subsequently reduced. The subtypes of DR beta 4 associated with DQ beta 3 (TA10+) were strongly associated with B44. The TaqI/DX alpha gene polymorphisms, as revealed by the DQ alpha cDNA probe, were found to be associated with DR beta allogenotypes.

Blood Donors↗

Molecular characterization of three HLA class II molecules on DR4 and DRw9 haplotypes: serologic and structural relationships at the polypeptides level.

By using alloantisera, three distinct HLA-D/DR region-encoded class II molecules were identified from cells carrying the HLA-DR4 and DRw9 haplotypes. Both DRw-53 and DQw3 molecules that bear the "supertypic" specificity were isolated independently from the DR antigen. The light chains of the DR4 antigens from different HLA-D types were distinct from one another, whereas the DRw53 molecules had identical charge and molecular weight in both heavy and light chains. On the other hand, the DQw3 molecules from the DR4 cell lines (Dw4 and Dw 10) were apparently identical but were polymorphic at least in the light chains among the DR4, DR5, and DRw9 haplotypes. In addition, monoclonal antibodies which specifically precipitate DR4 and DQw3 molecules have been isolated. The variable extent of homogeneity and diversity of three class II molecules may aid in our understanding of the role of class II antigens in the human immune regulation.

Antibodies, Monoclonal↗

Transcription of HLA class II genes in the absence of B-cell-specific octamer-binding factor.

HLA-DR and other human class II histocompatibility genes are expressed by Epstein-Barr virus-transformed B-lymphocyte cell lines but not by most T-cell leukemia lines. We determined by transcriptional run-on experiments that regulation of class II expression in these cells is at the level of gene transcription; nuclei isolated from B-cell lines actively transcribe class II mRNA, whereas nuclei from non-class II-expressing T-cell lines and from the class II transactive factor-deficient B-cell mutant 6.1.6 do not. In searching for DNA-binding proteins which might regulate transcription, we found both a ubiquitous (B1) and a B-cell-specific (B2) factor which bind to the octamer sequence ATTTGCAT 52 base pairs 5' of the cap site in the DR alpha gene. We examined the relationship of these factors to DR alpha transcription. HUT-78, a T-cell line which expresses class II mRNA constitutively, contains only the ubiquitous B1 octamer-binding factor also found in non-class II-expressing T-cell leukemias. Human fibroblast, HeLa, and melanoma cell lines similarly contain only the ubiquitous factor, even when these cells are induced to express class II mRNA by treatment with gamma interferon. Both B1 and B2 binding factors are present in the B-cell mutant 6.1.6, which nevertheless fails to transcribe class II mRNA. Although we have not ruled out the requirement of B-cell-specific octamer-binding factor B2 for class II expression in B cells, it is clear that in other cells substantial DR alpha transcription occurs in the absence of this factor.

B-Lymphocytes↗

HLA-class II genes modify outcome of Toxoplasma gondii infection.

Associations between Human Leukocyte Antigen (HLA) (i.e. human major histocompatibility complex [MHC]) genes and susceptibility to infections and inflammatory processes have been described, but causal relationships have not been proven. We characterized effects of HLA-DQ alleles on outcome of congenital toxoplasma infection and found that among Caucasians, the DQ3 gene frequency was significantly higher in infected infants with hydrocephalus (0.783) than infected infants without hydrocephalus (0.444) or published normal controls (0.487). We then developed a novel animal model to definitively determine the effect of these HLA DQ molecules on the severity of toxoplasmosis. Human MHC-Class II transgenes reduced parasite burden and necrosis in brains of mice infected with Toxoplasma gondii. Consistent with the observed association between DQ3 and hydrocephalus in human infants, in the murine model the DQ3(DQ8; DQB1*0302) gene protected less than DQ1 (DQ6; DQB1*0601). Our findings definitively prove a cause and effect relationship between human MHC genes and resistance to infection, provide novel means to characterise human immune responses that are protective or pathogenic in infections, and are important for vaccine development.

Animals↗

Complete nucleotide sequence of a functional HLA-DP beta gene and the region between the DP beta 1 and DP alpha 1 genes: comparison of the 5' ends of HLA class II genes.

The complete nucleotide sequence of an HLA-DP beta 1 gene and part of the adjacent DP alpha 1 gene, up to and including the signal sequence exon, were determined. The sequence of the DP beta 1 gene identified it as the DPw4 allele. The six exons of the DP beta 1 gene spanned over 11,000 bp of sequence. The arrangement of the gene was broadly analogous to genes of other class II beta chains. The beta 1 exon was flanked by introns of over 4 kb. Comparisons with published sequences of cDNA clones indicated that an alternative splice junction, at the 3' end of the gene, is used in at least one allele. Variation in choice of splice junction indicates an additional mechanism for allelic variation in class II genes. The sequence also indicated that the DP beta 1 and DP alpha 1 genes are separated by only 2 kb at their 5' ends. Comparison of the 5' ends of the DP alpha 1 and beta 1 genes with other class II sequences, including the DZ alpha gene, showed conservation of several blocks of sequences thought to be involved in control of expression. Some areas of the introns were partially conserved in the DQ beta gene, and several other intron sequences were homologous to sequences found in other unrelated genes.

Alleles↗

Gold induced nephropathy in rheumatoid arthritis and HLA class II genes.

OBJECTIVES: To elucidate the role of HLA-DRB, -DQA, and -DQB genes in patients with rheumatoid arthritis (RA) who developed gold induced nephropathy. METHODS: Southern blot analysis of HLA-DRB, -DQA, and -DQB genes was performed on DNA from 27 patients with RA with gold induced nephropathy, 37 patients with RA who were treated with gold but did not develop nephropathy, and 122 ethnically matched normal subjects. RESULTS: The 4.7 kb DQA1/Taq I band associated with DQA1*0501 and DR3 and DR5 was found in 16 (59%) patients with gold induced nephropathy compared with five (14%) patients without gold induced nephropathy. CONCLUSION: It is concluded that HLA-DQA region genes may be an important susceptibility factor for the development of gold induced nephropathy in patients with RA.

Arthritis, Rheumatoid↗

HLA class II DNA genotypes in Graves' disease: clues to inheritance of the HLA-linked component of susceptibility.

Restriction fragment length polymorphism analysis using DQ alpha, DQ beta and DR beta cDNA probes was performed in Graves' disease patients and control subjects. The following restriction fragment patterns were increased in frequency in patients compared with control subjects: 10 + 7.0 + 4.0kb DR beta/TaqI fragments (66% vs 32%; P less than 0.01; corrected P less than 0.06), 7.0 + 4.0kb DQ beta/BamHI fragments (55% vs 15%; P less than 0.001; corrected P less than 0.006), and a DQ alpha/TaqI 4.6kb fragment (75% vs 36%; P less than 0.005; corrected P less than 0.02). These associations could be accounted for by the known association of the B8-DR3 haplotype with the disorder. No non-DR3-related restriction fragment pattern was associated with the disease using any of the probes with restriction enzymes TaqI and BamHI. The 10 + 7.0 + 4.0kb DR beta/TaqI restriction pattern was identified in 23 of 35 Graves' disease patients. All 23 subjects were heterozygous for this pattern. This was inconsistent with simple recessive inheritance of the DR3-associated component of disease susceptibility (P = 0.01). The implications of these findings are discussed with reference to models for the inheritance of the HLA-linked component of Graves' disease susceptibility.

DNA Probes, HLA↗