A case of infantile systemic lupus erythematosus with severe lupus nephritis and EBV infection.

Infantile systemic lupus erythematosus (iSLE) is extremely rare. Patients with iSLE usually become severely unwell and have poor prognosis. Epstein-Barr virus (EBV) infection has been implicated in the development of SLE in both adults and children. Recently, we experienced a case of iSLE with severe lupus nephritis (LN) and EBV infection. A 14-month-old Japanese boy was diagnosed with iSLE according to the American Rheumatism Association criteria. Renal biopsy showed LN classified as International Society of Nephrology/Renal Pathology Society class IV-G (A), and liver biopsy showed lupus hepatitis. Steroid pulse treatment resulted in improvement of the levels of serological markers of SLE such as double-stranded DNA and complement, but his proteinuria worsened and he developed acute nephritic-nephrotic syndrome. Monthly intravenous cyclophosphamide (IVCY) therapy dramatically reduced his proteinuria and led to complete remission (urinary protein/creatinine ratio <0.1 mg/mg), with gradual improvement in levels of serological markers. EBV antibody titers and EBV polymerase chain reaction (PCR) of peripheral blood lymphocytes suggested that the onset of iSLE might have been associated with EBV infection. At his 2-year follow-up visit, he was healthy and remained in complete remission. We conclude that IVCY treatment might be well tolerated and effective in cases of iSLE. EBV infection might play an important role in the pathogenesis of iSLE.