Clinical and serological differences between systemic lupus erythematosus patients with antibodies to Ro versus patients with antibodies to Ro and La.

Among 55 systemic lupus erythematosus patients having antibodies to Ro and/or La, two major groups were distinguished by titration of sera in counterimmunoelectrophoresis. The first group (30 patients) had antibodies to Ro alone. This was associated with a high incidence of antibodies to DNA (77%) and serious renal disease (53%). The second group (23 patients) had antibodies to Ro and La, and this was associated with a lower incidence of antibodies to DNA (30%) and a very low incidence of nephritis (9%). In this group a phenomenon of linkage of anti- Ro and anti-La titers was observed. Additionally two patients with only anti-La were found. Neither had clinically apparent renal disease. Thus, systemic lupus erythematosus patients with anti-Ro fall into two subgroups that differ considerably in their prevalence of anti-DNA and serious renal disease.