Effect of treatment on Sézary cell count, histone acetylation, and lymphoma cells.

The graphs represent the WBC, absolute granulocyte count, and Sézary cell counts of patient 1 (panel A) and 2 (panel B) in response to treatment with depsipeptide. The x-axis indicates the days of the cycle; the arrows in the chart indicate the days that depsipeptide was administered. Below are peripheral mononuclear cells following fluorescent labeling with anti–acetyl histone H3. The majority of the cells are Sézary cells taken from the patients prior to infusion of depsipeptide, at the completion of the 4-hour infusion and (in panel B) at 24 hours after initiation of the infusion. In panel C, the section on the left was from a fine-needle aspiration biopsy prior to the initiation of therapy and demonstrates atypical lymphocytes with enlarged hyperchromatic nuclei and scant deep basophilic cytoplasm (Diff-Quick × 400). The section on the right was obtained after administration of the second dose of the first cycle and has cells with vacuolization of cytoplasm and fragmentation of nuclei (Diff-Quick × 400).