Hypogammaglobulinemia and Anti-CD20 Therapy-Induced Acute Thrombocytopenia: Perhaps More than a Coincidence?

Introduction: The development of secondary hypogammaglobulinemia (sHGG) because of tumor treatment and/or the primary underlying hematologic disorder holds substantial clinical significance. B-cell-derived malignancies and anti-CD20 monoclonal antibodies (mAbs) represent important risk factors for the development of sHGG. In addition, the occurrence of acute thrombocytopenia (AT) induced by anti-CD20 therapy is a known, albeit rare, phenomenon.

Case presentation: A 54-year-old patient experiencing the first relapse of classical follicular lymphoma has commenced salvage therapy following the R-DHAP protocol. After rituximab infusion, platelet count dropped from 116 × 109/L to 13 × 109/L within 24 h. Reduced immunoglobulin G levels indicated moderate HGG; thus, we immediately administered intravenous immunoglobulins (IVIg). Within 5 days after initiation of IVIg, platelet count increased and stabilized at >50 × 109/L.

Conclusions: It seems possible that anti-CD20 mAbs act like or activate similar mechanisms as autoantibodies in immune thrombocytopenia (ITP). Assuming that anti-CD20 therapy-induced AT is an ITP-like condition, HGG could be considered a potential risk factor. Thus, appropriate treatment of HGG with IVIg prior to anti-CD20 mAb therapy could potentially alleviate anti-CD20 therapy-induced AT.