Extracorporeal photopheresis in Sezary syndrome: hematologic parameters aspredictors of response

Data were analyzed from 23 patients with Sezary syndrome (defined by erythr oderma, more than 10% circulating atypical mononuclear cells, and periphera l blood T-cell clone) undergoing monthly extracorporeal photopheresis as th e sole therapy for up to 1 year. The cohort showed a significant reduction of skin scores during treatment (P = .001). Thirteen patients (57%) achieve d a reduction in skin score greater than 25% from baseline at 3, 6, 9, or 1 2 months (responders). Reduction in skin score correlated with reduction in the Sezary cell count as a percentage of total white cell count (P = .03). Responders and nonresponders were compared. None of the measured parameter s was significantly different between the 2 groups. It was assessed whether any of the baseline parameters predicted outcome. A higher baseline lympho cyte count was significantly associated with a decrease in skin score at 6 months (P < .05). A higher baseline Sezary cell count as a percentage of to tal white cell count predicted a subject was more likely to be a responder after 6 months of treatment (P = .021). No other parameters predicted respo nder status. These data show that the modest falls in CD4, CD8, and Sezary cell counts were seen in all patients and might have resulted from lymphocy te apoptosis. This mechanism could explain the more favorable response seen in patients with higher percentages of Sezary cells in the peripheral bloo d. Alternatively, minimum tumor burden might be required for the induction of a cytotoxic response. Analysis of tumor-specific cytotoxic T cells is ne eded to Investigate these possibilities further. (C) 2001 by The American S ociety of Hematology.