Sustained hypogammaglobulinemia under rituximab maintenance therapy could increase the risk for serious infections: a report of two cases.

We report two patients with granulomatosis with polyangiitis in remission with rituximab maintenance therapy with sustained hypogammaglobulinemia. Both patients had serious infections and were admitted to the intensive therapy unit. The patients had at least low IgM levels prior to the initiation of rituximab. They received cyclophosphamide and prednisolone at induction and at maintenance. They had lung affection, low level of both IgM and IgG and a cumulative dose of rituximab over 7 g at the time of the severe infection. Our patients have features similar to common variable immunodeficiency patients, and therefore prolonged very low levels of immunoglobulins could heighten the risk for severe infections.