Evaluation of cell death after treatment with extracorporeal photopheresis.

The aim of our study is to assess the mortality of leukocytes during extracorporeal photopheresis. Sixty-three photopheresis performed on 13 patients affected by chronic GvHD were evaluated. Samples were analyzed using a FACSCalibur flow cytometer. Apoptosis and necrosis of limphomononuclear cells dramatically increased after the apheretic procedure. We found a further increase of apoptotic and necrotic limphomononuclear cells after treatment with 8-MOP and UVA (p≤0.05). Our data suggested that the immunomodulatory effects of extracorporeal photopheresis, triggered by circulating apoptotic or necrotic cells, could play an important role in the treatment of GvHD with this procedure.