Transient regression in lymphocyte count in B-cell chronic lymphocytic leukemia after viral infection

Transient regression in the lymphocyte count of a patient with B-cell chronic lymphocytic leukemia (B-CLL) after viral infection is reported. A similar event occurred under natural interferon-α (IFN-α) treatment. It was confirmed that the event was not caused by a direct cytotoxic effect of IFN-α by analyzing the DNA fragmentation to estimate apoptotic and necrotic cell death before and after the administration of IFN-α. The study also suggested that the event was not caused by a cytostatic effect of IFN-α.