Comparison of clinical and serologic markers in systemic lupus erythematosus and overlap syndrome: a review of 247 patients.

To evaluate the relationship between clinical manifestations and serologic markers in patients with systemic lupus erythematosus (SLE) and patients with an overlap syndrome, we reviewed the charts of 247 such patients who had been examined between 1975 and 1979. All patients with an overlap syndrome had a high frequency of arthritis and Raynaud's phenomenon and a low frequency of renal disease regardless of the presence or absence of antibody to nuclear ribonucleoprotein (anti-nRNP) and antibody to Sm antigen (anti-Sm). The presence or absence of anti-nRNP and anti-Sm did not distinguish whether a patient had SLE or an overlap syndrome and could not be used to predict clinical manifestations of disease.