Successful treatment of X-linked lymphoproliferative disease (XLP) with anti-CD20 monoclonal antibody (Rituximab) followed by mismatched unrelated cord blood transplantation

A 4-year-old boy with X-linked lymphoproliferative disease (XLP) developed life-threatening acute lymphoproliferative crisis and failed to respond to conventional treatment of dexamethasone and etoposide. With the knowledge that uncontrolled alloreactive cytotoxic T-cell responses triggered by EBV-transformed B cells is the main cause of XLP, anti-CD20 monoclonocal antibody (Rituximab) which directed against B lymphocytes was use to damp down the patient's dysregulated immune response. He responded well to this novel approach and entered into complete remission with this treatment. His inherited immuno-deficient genetic defect was subsequently corrected by unrelated cord blood transplantation.