Analysis using two-dimensional (2D) gel electrophoresis of the 35S-methionine-labelled proteins synthesized by non-cultured total epidermal keratinocytes obtained from normal and psoriatic skin revealed 6 proteins that are strongly up-regulated (5 times or more) in psoriatic skin. These proteins are synthesized at albeit lower levels by keratinocytes from normal and normal-appearing (uninvolved) skin of psoriatic patients, and correspond to isoelectric focusing sample spot numbers 4311 (40.3 kDa), 4003 (12.4 kDa), 5008 (11.9 kDa), 3012 (11.6 kDa), 6016 (11.6 kDa) and 1015 (10;1 kDa) in the normal keratinocyte 2D gel protein database Celis et al, (1990) Electrophoresis, in press. These proteins are also detected in the labelling medium indicating that they are at least in part secreted. Given their striking regulatory behavior, these proteins may play a role in the pathogenesis of psoriasis.