Anti nucleic acid antibodies in systemic lupus erythematosus patients and their families. Incidence and correlation with lymphocytotoxic antibodies

Abstract

Anti-RNA antibodies were found in 82% of 28 systemic lupus erythematosus (SLE) probands and in 16% of 124 of their family members. The incidence in 76 control family members was only 5%. In the SLE family members, the antibodies were found exclusively in 21% of the 94 close household contacts of the probands. The incidence of anti native DNA (nDNA) antibodies was 68% for the SLE probands. The incidence of anti-nDNA antibodies in close household contacts of the probands was 6%, which was not significantly different from the 1% incidence found in control families. Lymphocytotoxic antibodies occurred in 57% of the SLE family members as a whole and in 68% of the close household contacts. In the SLE probands, lymphocytotoxic antibodies correlated with anti single stranded RNA (poly A) and anti-nDNA but not with anti double stranded RNA (poly Axpoly U). On the other hand, lymphocytotoxic antibodies in the household contacts correlated with anti double stranded RNA (poly Axpoly U) but not with anti poly A or anti nDNA. The anti-RNA antibodies were present in consanguineous household contacts but not in nonconsanguineous household contacts. These findings strengthen the hypothesis that both an environmental agent, possibly a virus, as well as the genetic response are important in the pathogenesis of SLE. Family members may, therefore, be a logical population in whom to search for specific antibodies to a viral agent.