Irreversible marrow aplasia after single course of 2-chlorodeoxyadenosine for hairy cell leukaemia preceding by A pandemic 2009-H1N1-associated pneumonia.

Hairy cell leukaemia (HCL) is a rare, indolent lymphoproliferative disorder characterized by varying degrees of cytopenias and the presence of malignant B cells with cytoplasmic projections. Cladribine (2-chlorodeoxyadenosine, 2-CdA) is an adenosine deaminase-resistant purine analogue and has been shown to be very effective as a first-line therapeutic option for HCL. The therapy with 2-CdA is found to be well tolerated with a paucity of toxicity. The common side effects include immunosuppression and reversible myelosuppression. We report a HCL patient with A pandemic 2009-H1N1-associated pneumonia who fully recovered after oseltamivir and antibiotics. The subsequent treatment with single 5-day course of 2-CdA resulted in persistent marrow aplasia with fatal systemic aspergillosis.