Severe Hypogammaglobulinemia Associated with Active Lupus Nephritis Treatment Resulting in Cytomegalovirus Infection

Patients with severe active lupus nephritis (LN) require immunosuppressive therapy to induce remission. However, the development of profound hypogammaglobulinemia causing cytomegalovirus (CMV) disease is a rare occurrence during standard immunotherapy. A 27-year-old woman who presented with active LN along with moderate renal impairment was treated with of mycophenolate mofetil (MMF) and methylprednisolone. MMF was soon switched with low-dose intravenous (IV) cyclophosphamide (CYC) owing to the development of posterior reversible encephalopathy syndrome and deterioration of renal function requiring hemodialysis. After two cycles of IV CYC, she developed CMV colitis and pneumonia. Although her serum immunoglobulin (Ig) concentrations before receiving immunosuppressive treatment were normal, they were profoundly reduced at CMV disease onset and continued to maintain low level for 30 months. Severe hypogammaglobulinemia can occur during standard therapy for LN, especially in patients with impaired renal function, pointing out the importance of close monitoring of Ig levels and CMV infection.