INTRODUCTION: Rheumatologic findings may be the first manifestation of primary humoral immunodeficiencies. The frequency of selective IgA deficiency in patients with juvenile idiopathic arthritis (JIA like) and juvenile systemic lupus erithematosus (JSLE) is 2% to 4% and 1% to 4%, respectively. OBJECTIVE: To describe patients with primary humoral immunodeficiencies associated with arthritis and to determine the prevalence of selective IgA deficiency within JIA and JSLE patients. PATIENTS AND METHODS: From January 1983 to December 2006, 4.876 patients were followed at the Pediatric Rheumatology Unit. A retrospective evaluation was performed in patients that presented arthritis as the first clinical manifestation of immunodeficiency. The humoral immunodeficiencies were classified into selective IgA deficiency, hypogammaglobulinemia and IgG subclass deficiency. RESULTS: Eleven patients (0.2%) had primary immunodeficiency: selective IgA deficiency occurred in 8, common variable immunodeficiency in two, and IgG subclass deficiency in one. Five of the 11 patients had an acute arthritis and six patients a chronic nonerosive arthritis (JIA-like). From the 253 JIA patients evaluated, 70 had IgA level evaluation done and 6 (8.5%) presented complete IgA deficiency (serum IgA < 7 mg/dl) (JIA-like). From the 45 JSLE patients with IgA levels evaluated, 3 (6.6%) had selective IgA deficiency diagnosis. CONCLUSION: The present study showed a low prevalence of humoral immunodeficiency in patients with rheumatic diseases. However, this association suggests that similar defects in immune response could be related to both diseases and that prospective studies are needed to elucidate this hypothesis.
arthritis; juvenile idiopathic arthritis; juvenile systemic lupus erythematosus; immunodeficiency