Flow cytometric quantification of UV-induced cell death in a human squamous cell carcinoma-derived cell line: dose and kinetic studies.

Exposure to ultraviolet (UV) radiation and photochemotherapy induces apoptotic cell death in epidermal cells. In this study annexin V binding and propidium iodide (PI) uptake have been measured by flow cytometry to evaluate UV-induced cell death in the human squamous cell carcinoma-derived cell line A 431. Physiological and therapeutical relevant doses of UVA, UVA1, UVB, narrow-band UVB (311 nm) and photochemotherapy using 100 ng/ml of 8-methoxypsoralen (8-MOP) with UVA or UVA1 (PUVA or PUVA1) have been applied. Doses ranged from 8 to 96 J/cm2 for UVA1 and UVA, from 8 to 128 mJ/cm2 for UVB, from 256 to 4096 mJ/cm2 for narrow-band UVB (311 nm) and from 1 to 16J/cm2 for photochemotherapy. Results show that the amount of annexin V binding, a measure of early apoptosis, as well as PI uptake, a parameter of ultimate cell death, are strictly correlated with the applied UV dose. Peak values of annexin V-positive cells are noted 12 h after UV exposure in all protocols and are followed by an increase of PI-uptaking cells with peak values at 24 h after UVA and UVA1, and 48 h after PUVA, PUVA1, UVB and narrow-band UVB. To compare the effect of different wavelengths and light sources, dose equivalents are calculated based on the induction of 50% cell death (as determined by PI uptake). The equivalents are 96 J/cm2 for UVA and UVA1, 16 J/cm2 for PUVA and PUVA1, 256 mJ/cm2 for UVB and 2048 mJ/cm2 for narrow-band UVB. Our results establish annexin V/PI double staining as an appropriate method for the quantification of UV-induced cell death. Moreover, they provide a basis for further investigations concerning mechanisms and modifications of UV-induced apoptosis.

"High-dose" UVA1 therapy of widespread plaque-type, nodular, and erythrodermic mycosis fungoides.

BACKGROUND: UVA1 (340 to 400 nm) was found to be effective in the treatment of early-stage mycosis fungoides (MF). OBJECTIVE: The purpose of this study was to assess the efficacy of UVA1 phototherapy for widespread plaque-type, nodular, and erythrodermic MF. METHODS: Thirteen patients (8 with stage IB, 4 with IIB, and 1 with III MF) received 100 J/cm(2) UVA1 daily until remission. Four patients also had lesions inaccessible by UVA1 that were considered control lesions. Immunocytologic studies of skin infiltrates and circulating T cells were done before and after the therapy. RESULTS: Eleven patients showed complete clinical and histologic responses. Two patients had a partial improvement. Unirradiated control lesions never improved. Serious short-term side effects were not recorded. Circulating CD4(+)/CD45RO(+) and CD4(+)/CD95(+) lymphocytes were significantly reduced by the therapy. CONCLUSION: UVA1 therapy is an effective and well-tolerated treatment for advanced MF. The therapeutic relevance of the effects on circulating lymphocytes remains to be established because lesions in nonexposed cutaneous areas did not respond.