To analyse the clinical features and pathogenesis of overlapping features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), termed 'Rhupus syndrome'.
Twenty-four patients with Rhupus syndrome were identified over the last two decades. The clinical features of these patients were described and the literatures about this disease were reviewed.
Twenty-four patients (twenty-three women, one man) were enrolled with an average age of 45.5 years. The mean age at presentation was 36.8 years. Nineteen of the patients initially present with erosive RA and developed SLE over about 7.7 years. In 14 patients who had convincing personal histories, 4 had pregnancies, 2 had dysmenorrhea and one had ovary cyst before poly arthritis developed. Ten of these patients were associated with menopause during transitions from RA to SLE. Expression frequencies of RA associated antibodies were similar as other RA patients. SLE associated manifestations were moderate in Rhupus syndrome especially severe renal damage. Hematopoietic system manifestations were prominent in this population.
Most of the Rhupus syndrome patients firstly presented with RA and showed less SLE associated severe damages. Sex hormone factor might be associated with the incidence of the disease.