The combination of two chemotherapeutic drugs, fludarabine and cyclophosphamide (FC), with the rituximab (RTX) – FCR – in the treatment of chronic lymphocytic leukemia (CLL) is associated with a high complete remission rate. In recent years FCR has become the first-line choice for CLL patients under 65 year of age. Delayed leucopenia has been described in rituximab-treated CLL patients. However among reported cases, the late onset and progressive lymphopenia was not noticed in individuals with CLL.
The present study reports the case of a 53-year-old Caucasian man who developed prolonged progressive lymphopenia after 18 weeks RTX treatment-free period. Irrespective of no drug intake, in 13-week follow up, the amount of B lymphocytes as well as the serum levels of IgG decreased (93.22% and 20% reduction, respectively). Progressive neutropenia with hypogammaglobulinemia has constantly intensified leading to the necessity of gamma globulin supplementation and administration of granulocyte colony-stimulating factor (G-CSF). The present findings suggests that FCR therapy in some individuals may lead to the induction of persistent alteration of the cellular and humoral immunity.