HLA CLASS-II GENES AND ANTIBODIES AGAINST RECOMBINANT U1-NRNP PROTEINS IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

To investigate a possible involvement of HLA-class II alleles in the g enetic predisposition for the formation of anti-U1-nRNP antibody in sy stemic lupus erythematosus (SLE), genomic DNA of 178 patients was type d for the DRB1, DQA1 and DQB1 alleles using a polymerase chain reactio n (PCR) and non-radioactive-oligonucleotide typing. Antibodies against recombinant U1-nRNP proteins (U1-A-, U1-C- and 70K-protein) were dete rmined by ELISA. Anti-U1-C antibody was found in 26 (14.7%), anti-U1-A in 34 (19.2%) and anti-70K in 17 (9.6%) patients. A joint occurrence was observed for these antibodies against the recombinant U1-nRNP prot eins: anti-U1-C and anti-U1-A antibodies occurred together more freque ntly than alone and than together with anti-U1-70K antibodies. The fre quency of DRB104 was slightly increased in the patients with anti-U1- C as compared to the patients without anti-U1-C (P<0.05, Pcorr = n.s., RR = 2.4). The DQA10301 allele, which is in linkage disequilibrium w ith DRB104, is found more frequently in anti-U1-C-positive than in an tibody-negative patients. The DQB10303 allele, detected in 12 of 176 SLE patients, was absent in the patients with any of the antibodies ag ainst the U1-nRNP proteins. All these deviations may be due to chance alone. We concluded that the presence of antibodies against recombinan t U1-nRNP proteins was not significantly associated with any HLA DRB1, DQA1 and DQB1 allele in our group of SLE patients.