nous porphyrins after exogenous administration of ALA. The same studies also showed that inactivation of ALA-treated T cell lymphoma Eb-Esb cells occurred after photoexcitation by visible light. Malik et a1.9 speculated that the accumulation of porphyrins in lymphoma cells may be caused by a lack of ferrochelatase, which is needed for the insertion of iron into the porphyrin ring in the mitochondria of leukemic cells. Thus the efficiency of PDT after ALA photosensitization in MF may be based on direct cytotoxic mitochondrial damage to T lymphocytes in the skin. Our results showing the efficacy of ALA photosensitization in PDT for MF suggest further studies to determine the optimal ALA and light dose combination, frequency of treatment, and duration of remission. Furthermore, the findings also suggest that, provided an appropriate light source becomes available for exposing larger body areas to visible light, topical3, 6, 7 or systemic8, 12 ALA photosensitization may be effective in PDT for more widespread and extensive MF.