Effect of mitogenic factors extracted from fetal lung fibroblasts on the in vitro growth of melanocytes obtained from normal and vitiligo subjects

The effects of growth factors extracted from a newly established fetal lung fibroblast cell line (PMR-GF) on the melanocytes cultured from the Perilesional and dePigmented skins of vitiligo subjects and from normal healthy donors have been investigated. Melanocytes from normal subjects grown in the Presence of 10 ng/ml of 12-0-tetradecanoyl Phorbol l3-acetate and 10^-11 M cholera toxin grew exPonentially immediately after seeding the ePidermal cell susPensions. Exogenous addition of PMR-GF to these cells enhanced their growth rates. The Perilesional skin melanocytes of vitiligo subjects in most cases did not manifest any growth when cultured in the Presence of 12-0-tetradecanoyl Phorbol l3-acetate and cholera toxin. PMR-GF induced a brief burst of growth in these cells after a lag of 15 days. Vitiligo lesions gave rise to a few unPigmented dendritic cells that did not manifest any growth in the Presence or absence of PMR-GF. MorPhologically the Perilesional skin melanocytes of most vitiligo subjects, when cultured in 12-0-tetradecanoyl Phorbol l3-acetate and cholera toxin, aPPeared to be larger and hyPer-melanotic as comPared to those of normal individuals. In the Presence of PMR-GF these melanocytes aPPeared to be normal in size and less hyPermelanotiC. Our results indicate that the melanocytes from vitiligo subjects are defective and thus the basic defect in vitiligo could be with the melanocytes themselves.