Proliferation and effects of UVA irradiation in cultured fibroblasts from lesions in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (LE) often presents clinically as chronic cutaneous lesions, healing with scar formation, and acute cutaneous lesions that are seen in systemic and subacute LE and heal without scarring. UV-light plays a role in the pathogenesis of the skin lesions, but the pathomechanism is still unclear. The aim of this study was to compare fibroblast proliferation and response to UV-light by cultured fibroblasts from scarring and non-scarring LE lesions. Fibroblasts were cultured from skin lesions from 5 patients with classic discoid LE, 5 patients with subacute cutaneous LE and healthy, age-matched donors. Proliferation rate was assessed by cell counts at days 3, 6 and 9. The fibroblast cultures were irradiated with UVA and the supernatants were analysed for IL-6, TGF-beta, IL-4, soluble ICAM-1 and soluble VCAM-1. Fibroblast cultures from scarring lesions showed significantly lower cell-counts at days 3 (P = 0.01) and 9 (P = 0.009), than cultures from nonscarring lesions or controls. There were no significant differences in levels of IL-6 or TGF-beta in supernatants of irradiated fibroblasts from patients compared to controls and IL-4 and the soluble forms of ICAM-1 and VCAM-1 were below detection level. The response to UV-irradiation was similar to that of normal cells in the parameters studied. In summary, cultured fibroblasts from scarring LE lesions displayed significantly decreased proliferation rates compared to non-scarring LE lesions and controls. This may be secondary to inflammatory factors, or due to a functional defect in LE fibroblasts.