Intra- and inter-individual variations in cornified envelope peptide composition in normal and psoriatic skin.

Cornified envelopes from the stratum corneum of healthy volunteers and from the involved and uninvolved skin of psoriatic patients were electrophoretically purified, and their peptide composition analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) after cyanogen bromide cleavage. The resulting envelope peptide patterns (EPPs) were compared. In normal subjects, mainly quantitative minor differences in the EPPs were observed between different individuals. In the same individual, palms and soles could be distinguished from other body sites by their EPPs. The palm and sole samples presented identical patterns which were different from the patterns found with samples from other body sites. In psoriatic patients, EPPs of uninvolved skin resembled closely those of healthy epidermis, but showed striking differences from those of lesional skin. The EPPs of psoriatic lesional skin showed a characteristic accumulation of small peptides with molecular weights of 3-11 kDa. The EPP of lesional skin returned to normal during PUVA therapy, indicating that the changes in the biochemical composition of the cornified envelope are correlated with the clinical status of the disease.