The cytolytic effect of PUVA treatment on PHA-stimulated human peripheral lymphocytes.

The morphology of PUVA-treated and PHA-stimulated human peripheral lymphocytes in vitro was studied by means of the light and electron microscopes. Most cells showed signs of cytolysis, such as pyknotic nuclei and a swollen and decomposed cytoplasm; a few cells, however, appeared as normal lymphoblasts. In the latter, repair-enzyme mechanisms may successfully have rectified alterations in the DNS prior to the inception of S-phase. These findings are discussed with reference to the in vivo effect of PUVA treatment.