OCCURRENCE OF AUTOIMMUNE-DISEASES AND RELATIONSHIP OF AUTOANTIBODY EXPRESSION WITH HLA PHENOTYPES IN MULTICASE RHEUMATOID-ARTHRITIS FAMILIES

Presence of autoimmune diseases and relationship of autoantibody expre ssion with HLA association has been studied in 44 multicase rheumatoid arthritis (RA) families of Asian Indian origin. An increased prevalen ce of systemic lupus erythematosus (SLE) was observed in relatives (2. 3%). Although HLA-DR4 segregated preferentially with seropositivity in general, no difference was observed among seropositive versus seroneg ative RA. On the other hand, no HLA association was observed with ANF positivity in these families. An increased frequency of DR7 in the ANF negative and RF negative group of RA patients compared to positive gr oups suggests that it may act as protective element for the developmen t of autoantibodies in RA. An increased occurrence of DR4 in relatives affected with SLE was observed. While RA segregated mostly with HLA-D R4 in these families, autoimmune thyroid disease and insulin dependent diabetes mellitus (IDDM) segregated with HLA-DR3 suggesting the invol vement of at least two sets of HLA-linked autoimmunity favouring susce ptibility genes in the Indian population.