FULL-LENGTH CDNA NUCLEOTIDE-SEQUENCE OF A SEROLOGICALLY UNDETECTABLE HLA-DQA1 ALLELE - HLA-DQA1-ASTERISK-LA

This study describes the characterization of a serological HLA-DQ ''bl ank'' specificity that segregates with the HLA-A2, -B7, -DR14, -DR52 h aplotype. Although conventional serological typing techniques could no t detect an HLA-DQ product on the haplotype positive for the HLA-DQ '' blank'' specificity. sequence-specific oligonucleotide (SSO) dot-blot analysis demonstrated the presence of the HLA-DQA101 and HLA-DQB1*05 alleles. Full-length cDNA nucleotide sequence analysis revealed that t he HLA-DQB1 allele that segregated with the HLA-DQ ''blank'' specifici ty was identical to HLA-DQB105031. As for the HLA-DQA1 allele, one nu cleotide substitution distinguished the HLA-DQA1 ''blank'' allele from HLA-DQA10104. In exon 2 at nucleotide position 301 a C was substitut ed for a T (Arg-->Cys). Pending official recognition by the WHO Nomenc lature Committee, this HLA-DQA1 ''blank'' allele is termed HLA-DQA1'' LA''. Furthermore, it is postulated that the introduction of cysteine at amino acid position 102 abrogates the classical HLA-DQ1 specificity .