The human peripheral lymphocyte?a model system for studying the combined effect of psoralen plus black light

Abstract

The effect of psoralen plus long wavelength ultraviolet light (UVA) on 3H-thymidine uptake of PHA stimulated human lymphocytes was investigated. PHA induced lymphocyte transformation was inhibited by the combined action of psoralen and UVA irradiation in a dose related manner. Inhibition of DNA-synthesis occurred at concentrations of psoralen that can be expected in the serum of patients treated by systemic photochemotherapy. No effect was noted at these psoralen concentrations in the absence of UVA irradiation. Also did UVA irradiation in the absence of psoralen not inhibit 3H-thymidine incorporation into PHA stimulated lymphocytes.

Increased proliferation of phytohaemagglutinin (PHA)-stimulated human leucocytes after 8-methoxypsoralen treatment

“…8-MOP had no effect on nonstimulated cells (unpublished data). The increase in cell proliferation is in contradiction to the results of other authors claiming no effect of 8-MOP at therapeutic concentrations (Scherer et al 1977;Gast et al 1985).…”

“…The mechanism of action of 8-MOP on lymphocyte proliferation without photoactivation, is not understood. Some reports indicate no effect (Scherer et al 1977;Gast et al 1985), others describe a negative effect on viability and proliferation as well as mutagenic action (Lischka & Decker 1978;Abel & Schimmer 1981).…”

Breast cancer cell survival signal is affected by bergapten combined with an ultraviolet irradiation

“…The effectiveness of the psoralen compounds has been attributed to their DNA photobinding properties, thereby preventing cellular division [6][7][8][9][10].…”

“…Evidence has been provided that these photoactive compounds can interact with cellular macromolecules and can interfere with DNA synthesis, as reported in many cell types including fibroblast, keratinocytes, melanocytes or leukocytes [6][7][8][9][10].…”

Pityriasis lichenoides chronica – eine neue Indikation zur PUVA-Therapie?

“…Der histologisch nachweisbare Rückgang des dermalen, vorwie gend lymphozytären Infiltrates bei der Mycosis fungoides unter der PUVATherapie [8] liess vermuten, dass der Angriffspunkt der PUVA-Therapie das dermale Infiltrat ist. Neuere Untersuchungen konnten bestätigen, dass die die Zellproliferation hemmenden Vorgänge nicht nur an epidermalen [21], sondern auch an dermalen Zellen sowie an Lymphozyten [19] stattfinden. Neueste Ergebnisse weisen darauf hin, dass auch 8-MOP-Proteinkomplexe entstehen [12], Es ist daher anzunehmen, dass der Erfolg der PUVA-Therapie bei der Pityriasis lichenoides chronica auch auf der Beseitigung des dermalen Infiltrates beruht, zumal die epidermalen Veränderungen bei der Pityriasis lichenoides chronica reaktiv und somit wohl sekundärer Natur sind.…”