Lymphocytotoxic antibodies in SLE patients and their relatives.

A search for lymphocytotoxic antibodies in 50 SLE patients and in 109 of their blood relatives revealed an incidence of cold-reacting antibodies of 80% and 39% respectively, as compared with 15% in 110 normal blood donors paired for age, sex, and racial origin. The antibodies were also present in 7 of 18 (39%) of the spouses of SLE patients. Lymphocytotoxic antibodies exhibited broad reactivity in all groups, although positive SLE sera showed a tendency to react with a wider variety of lymphocytes and to present higher titers than positive sera from the other groups tested.