Cardiac tamponade due to systemic lupus erythematosus in a 7-year-old boy with selective IgG subclass deficiency

Systemic lupus erythematosus (SLE) was observed in a 7-year-old boy with IgG₂ and IgG₄ subclass deficiencies who had been treated with immunoglobulin (100–200 mg/kg/4 weeks) since 2 years of age. The mother and the half-brother displayed the same deficiency. Serum IgG mainly consisted of IgG₁ (98.9%) during the acute phase of SLE due to transient IgG₃ deficiency. While he had no common manifestations of SLE such as arthritis or nephropathy, he developed cardiac tamponade due to massive pericardial effusion. Conclusion The clinical features of SLE in the present case such as the development of cardiac tamponade and the absence of renal involvement may result from the markedly imbalanced IgG subclass distribution among auto-antibodies. Received: 20 May 1997 and in revised form: 7 October 1997 / Accepted: 21 October 1997