Extracorporeal Photopheresis of Cutaneous T-Cell Lymphoma Is Associated with Reduction of Peripheral CD4+ T Lymphocytes

Abstract

Background: Extracorporeal photopheresis (ECP) has been successfully introduced for the treatment of cutaneous T-cell lymphoma; however, the mechanism(s) of its action is (are) unknown. Objective: To investigate the effects of ECP on the immune system of patients with cutaneous T-cell lymphoma. Methods: Clinical response and changes of lymphocyte subpopulations in 20 patients with cutaneous T-cell lymphoma under ECP monotherapy or combined regimens were evaluated and compared after 3, 6 and 12 ECP cycles. Results: Thirteen of 20 patients showed a ≥50% reduction of skin lesions after 6–12 ECP cycles. An overall T-lymphocyte reduction was assessed with a balanced CD4+ T-helper and CD8+ T-suppressor cell decrease in responders. In contrast, there was a trend of CD4+ T-helper cell increase in nonresponders which could result from the failure of treatment to control the natural course of the disease. The CD4+/CD8+ ratios were 1.6 at baseline and 1.4 after 12 cycles in responders, while they increased from 1.7 to 4.1 in nonresponders, respectively (p = 0.047). In addition, there was an overall decrease in the CD57+/CD8+ T-cell subpopulation mostly due to a reduction in the responder group. Conclusion: The marked differences detected in certain T-cell subpopulations suggest an effect of ECP on peripheral T lymphocytes and, especially, on CD4+ cells.