HLA class II allelic variation and susceptibility to pemphigus vulgaris.

Abstract

The autoimmune dermatologic disease pemphigus vulgaris (PV) is associated with the HLA serotypes DR4and DRw6. Susceptibility to PV could be conferred either by sequences shared between the DR4 and DRw6 haplotypes or by different sequences in these haplotypes. We have examined the distribution of DR and DQ fl-chain and DQ a-chain alleles in PV patients and in control subjects by hybridization with oligonucleotide probes and sequence analysis of in vitro ampli- (8). In population studies, PV is strongly associated with the serotypes HLA-DR4 and HLADRw6 (9, 10), with <5% of the patients possessing neither marker. Disease associations with two different HLA haplotypes could mean either that these two haplotypes share a common allele or epitope or that different alleles in the two haplotypes can confer disease susceptibility.As noted above, molecular analysis of serologically defined class II haplotypes (e.g., DR4 and DRw6) has revealed significant variation at the DR and DQ loci. Sequence analysis of class II genes from various haplotypes demonstrated that a DR/I epitope at amino acid positions 67-71 (termed here "IDE", based on one-letter symbols for Ile-67, Asp-70, and Glu-71) was shared between a subset of DR4 haplotypes ("DwlO") (11) and a subset of DRw6 haplotypes (DRw13) (ref. 12 and unpublished data). This observation suggests that these shared polymorphic residues of the DR,8I chain, which determines the DR specificity, may contribute to PV autoimmunity and account for both the DR4-and the DRw6-associated susceptibility. However, Szafer et al. (10) reported that specific restriction-fragment length polymorphisms (RFLPs) detected with a DQP cDNA probe subdivided the DR4 and DRw6 haplotypes and showed significantly higher associations with PV than did the serologic markers. Analysis of allelic coding-sequence variation in patients and in controls is needed to identify the putative class II alleles or epitopes that contribute to PV.Sequence analysis of DR,3I, DRfIII, and DQB alleles from three U.S. DR4+ PV patients (DR4/4, -4/5, and -4/5) revealed that all the patients had the Dw1O DRf3I allele (13) found in only 10o of U.S. DR4+ controls (14). Further, three of the four DQP alleles from the DR4 haplotypes were the DQB3.2 allele present in 60-80% of control DR4 haplotypes. These sequence data, although obtained from only three patients, suggest that, for the DR4 susceptibility to PV, the Dw1O DR,6I allele may contribute to autoimmunity but that the DQ, allele does not. These data were obtained by using the polymerase chain-reaction (PCR) method for the in vitro amplification of specific genomic sequences (15)(16)(17).We report here the use of sequence-specific oligonucleotide (SSO) probes to determine the distribution of DR4 DRBI and DQB alleles in a panel of PV patients and controls. The frequency of the IDE sequence in patient and control DRw6 haplotypes was also determined, to test the "shared epitope" model of PV susceptibility. In addition, we describe the Abbreviations: PV, pemphigus vulgaris; ...

Specific HLA-DQB and HLA-DRB1 alleles confer susceptibility to pemphigus vulgaris.

“…Thus, the observed distribution of DRBI and DQB alleles among DR4+ PV patients and controls suggested that the Dw10 DRB1 allele was responsible for the observed association with DR4. The Dw1O DRBJ allele differs from the other DRBJ alleles of the DR4 haplotype in the third hypervariable region in containing the "IDE" (Ile-67, Asp-70, and Glu-71) epitope which is, therefore, implicated in the susceptibility of DR4' individuals to PV (10)(11)(12). Although the same IDE epitope is found in the third hypervariable region of the most-common DRw6 DRBI allele, 6A (Fig.…”

“…Analysis of PCRamplified DNA from a panel of DR4' PV patients and controls with a set of DRBJ SSO probes revealed that nearly all (>95%) DR4+ PV patients carried the Dw10 DRBI allele, while the frequency of the oligonucleotide-defined DwJO DRBE allele in the HLA-matched control group was 5% (U.S. controls) (9) and 60% (Israeli Jewish controls) (10). In addition, sequence and SSO analysis of the DQB allele carried by the DR4+ PV and control groups showed that 92% of both patients and controls contained the DQB3.2 allele (10).…”

“…This allele differed from another common DQB allele (DQBJ.1) by only a valineto-aspartic acid substitution at position 57 of the DQ 1 chain and is associated with the Dw9 subtype of DRw6. Some individuals in both the patient (n = 3) and control (n = 1) population failed to hybridize to either of the two probes (CRX02 and CRX03) used to distinguish the sequences around codon 57 (10). We speculated that these DQB alleles might represent uncharacterized sequence polymorphisms (10 (13).…”

“…Some individuals in both the patient (n = 3) and control (n = 1) population failed to hybridize to either of the two probes (CRX02 and CRX03) used to distinguish the sequences around codon 57 (10). We speculated that these DQB alleles might represent uncharacterized sequence polymorphisms (10 (13). The DRBI 6C allele was derived from the DRw6+ homozygous typing cell (HTC) "Amala."…”

“…Amplified DNA was analyzed by filter dot-blot hybridization with SSO probes as described (8,10; Table 1 (9,10), which amplify all DRB loci and alleles. The upper row of samples was amplified with the DRw6 DRBI-specific primers CRX11/GH50.…”