Abstract
Fibroblasts were cultured from the involved and uninvolved forearm skin of patients with severe generalized psoriasis and compared with those from the forearms of normal controls of similar ages. Thirteen strains were obtained from involved skin (PSA strains) and 16 strains from uninvolved skin (PSB), with 13 control strains (NSF). Outgrowth of fibroblasts form the psoriatic skin explants was slightly quicker than from control skin, and the average proliferation rates of passaged strains were PSA 144, PSB 134 and NSF 94 (P < 0.05). Psoriatic fibroblasts were abnormally dependent on serum for anchorage. In serum-free medium many cells rounded up and were only loosely attached to the substratum. This effect was rapid, reversible and not corrected by adding fibronectin. Cell attachment assays showed only small differences betwen the psoriatic and normal fibroblasts and the main effect effect of serum withdrawal appeared to be on spreading rather than on attachment. Apparently, the dermis of both involved and uninvolved psoriatic skin is abnormal, and the hyperactivity persists in vitro. Findings seem most compatible with a hyperproliferative reaction of both epidermis and dermis to an extracutaneous, perhaps vascular, stimulus.