Hypersensitivity of skin fibroblasts from patients with chronic actinic dermatitis to ultraviolet B (UVB), UVA and superoxide radical.

The sensitivity of fibroblasts derived from patients with chronic actinic dermatitis (CAD) ultraviolet B (UVB), UVA and superoxide radical was examined. Fibroblasts from the skin of 3 patients with CAD showed abnormal hypersensitivity after exposure to mid-UV (UVB) and near-UV (UVA) radiation in both the dividing and quiescent phases. In their dividing phases, the 3 cell strains (CAD1TO, CAD2TO and CAD3TO) exhibited 78, 55 and 82 J/m2 for the mean lethal dose (Do) values in UVB survival curves. In the quiescent phases their Do values were 262, 226 and 165 J/m2, respectively. Regarding UVA sensitivity, Do value in the dividing phases were 4.9, 3.9 and 3.8 x 10(4) J/m2, and in the quiescent phases, 2.0, 1.9 and 1.7 x 10(5) J/m2. Do values were lower than in the cell strains derived from healthy individuals (Do = 120 +/- 18 and 390 +/- 72 J/m2) for UVB sensitivity in the dividing and quiescent phases and (5.9 +/- 0.6) x 10(4) and (3.2 +/- 1.0) x 10(5) J/m2 for UVA sensitivity in the dividing and quiescent phases. DNA repair synthesis was similar between the cell lines. Furthermore, the 3 CAD cell lines showed a higher sensitivity to superoxide radical generated by hypoxanthine/xanthine oxidase treatment. These results suggest that patients with CAD may suffer from a defect in dealing with damage induced by oxygen radicals.