Transient eosinophilia in a patient with hairy-cell leukaemia treated with 2-chlorodeoxyadenosine.

Eosinophilia may be associated with various pathologic states such as malignant disorders, atopic and parasitic diseases, certain infections, as well as drug reactions. We describe a case of a 48-year-old patient who was submitted to a single-course therapy with 2-chlorodeoxyadenosine because of hairy-cell leukaemia and previously did not respond to splenectomy. After the treatment marked transient eosinophilia appeared which preceded the achievement of complete remission. It is supposed that eosinophilia might have been caused by the release of cytokines from damaged leukaemic cells.