A photochemotherapy based on the synergistic action of 8-methoxypsoralen (8-MOP) and long wavelength ultraviolet light (UVA, 320-400 nm) has been used extensively since 1974 for the treatment of psoriasis, a hyperprolifierative disease of the skin. More recently, this photochemotherapy has been used for the extracorporeal irradiation ot the blood of cutaneous T cell lymphoma (CTCL) patients in the leukemic stage of the disease. 8-MOP is ingested; two hours later when peak blood levels have been achieved the affected tissue is irradiated (skin in psoriasis and blood in CTCL). Using 8-MCP-DNA photoadduct formation as a cheillical actinometer, the effective dose of UVA radiation delivered to lymphocytes during photochemotherapy in the presence of erythrocytes was found to be ~1 J/cm2. In addition, a monoclonal antibody prepared in our laboratory was used in competitive ELISA assays to quantify the formation of 8-MOP photoadducts during the photochemotherapy.
Francis P. Gasparro,
"Extracorporeal Photochemotherapy Of Cutaneous T Cell Lymphoma.", Proc. SPIE 0847, New Directions in Photodynamic Therapy, (19 February 1988); doi: 10.1117/12.942691; https://doi.org/10.1117/12.942691