Incidence and Correlation with Lymphocytotoxic Antibodies

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. Received for publication 25 April 1975 and in revised form 9 July 1975. INTRODUCTION Immunologic and viral factors are important in the etiology and pathogenesis of systemic lupus erythematosus (SLE)1 (1-3). Studies in the New Zealand black (NZB) mouse (4) as well as in the dog model for SLE (5) have implicated viral factors in the etiology and pathogenesis of the disease that develops in these animals. Lymphocytotoxic antibody is found both in the NZB mouse (6) and in a large percentage of SLE patients (7). It also occurs in a significant proportion of family members of SLE patients, especially in individuals with close household contact (8). SLE patients have elevated antibody titers to a variety of viruses (9, 10), to reovirus RNA (11), and to singleand doublestranded RNA (12). Similar anti-nucleic acid antibodies, both anti-RNA and anti-DNA, are found in the NZB mouse model for SLE (13). The present study had two purposes: to determine if anti-nucleic acid antibodies occur in lupus family members, and if so, whether any correlation exists between specific anti-nucleic acid antibodies and lymphocytotoxic antibodies either in the SLE patients or in their relatives.