Wh. Boehncke et al., COMPARISON OF SENSITIVITY TOWARDS PHOTODYNAMIC THERAPY OF CUTANEOUS RESIDENT AND INFILTRATING CELL-TYPES IN-VITRO, Lasers in surgery and medicine, 19(4), 1996, pp. 451-457
Background and Objective: Photodynamic therapy (PDT) combines photosen
sitizers absorbing light in the visible spectral region and irradiatio
n with light of corresponding wavelengths. We analysed the sensitivity
of cell lines established from resident cutaneous cells and from tran
sformed lymphocytes towards PDT.Study Design/Materials and Methods: PD
T was performed employing either 630 or 662 nm light or polychromatic
red light (600-700 nm) and photosensitizers Photosan-3, delta-aminolev
ulinic acid, or methylene blue. Proliferation measured by H-3-TdR upta
ke was determined in human immortalized keratinocytes (HaCaT) and mous
e fibroblasts (NIH/3T3) in comparison to human transformed T-(HuT78) a
nd B-lymphocytes (RA1). Additionally, uptake of the photosensitizers w
as estimated employing video-intensified fluorescence-microscopy (VIFM
). Results: Depending on the photosensitizer tested HaCaT and NIH/3T3
exhibited an ED(50) up to 10-fold as high as the lymphocytic lines. Po
lychromatic red light was at least as effective at inducing photodynam
ic reactions as 630 or 662 nm light. VIFM revealed a positive correlat
ion between sensitivity of a given cell type towards PDT and uptake of
the photosensitizers. The differential uptake observed in vitro was c
onfirmed in vivo: A photosensitizer applied topically on a lesion of a
patient with mycosis fungoides was found to accumulate preferentially
in the lymphocytic infiltrate. Conclusion: Selective topical polychro
matic PDT seems to be a feasible goal for the treatment of cutaneous l
ymphomas. (C) 1996 Wiley-Liss, Inc.