NO DIRECT CORRELATION BETWEEN HLA-DPB1 AND ANTIBODIES AGAINST RECOMBINANT RO (SS-A) LA(SS-B) PROTEINS IN SYSTEMIC LUPUS-ERYTHEMATOSUS/

We investigated the association of HLA-DPB1 alleles with the occurrenc e of autoantibodies against Ro (SS-A) or La (SS-B) using recombinant 5 2 kD-Ro, 60 kD-Ro and La proteins in 177 German patients with systemic lupus erythematosus (SLE). A significant increase in the frequency of DPB10101 is observed in SLE patients compared to healthy controls (P (corr.) .<0.004). Antibodies against 52 kD-Ro, 60 kD-Ro and La are tes ted by ELISA and are found with a frequency of 25.4%, 33.9% and 17.5% in the patients, respectively. An association with HLA-DPB10101 is ob served for antibodies against La (P<0.01) and 52 kD-Ro (P<0.01), but n ot for 60 kD-Ro in the absence of La/52 kD-Ro. Since there is a strong linkage disequilibrium between DPB10101 and DR3 in the normal popula tion and in SLE patients, and since there is an association between DR 3 and SLE, as well as between DR3 and the occurrence of recombinant Ro /La antibodies in SLE patients, we investigated whether DPB10101 is a ssociated per se or via linkage disequilibrium with DR3. DPB10101 in the absence of DR3 is not more common in patients than in controls and not in patients with autoantibodies to Ro and La than without antoant ibodies. We conclude that there is no evidence for a direct involvemen t of DPB10101 in the production of Ro/La autoantibodies in SLE patien ts.