Psoriatic hyperproliferative epidermis is characterized by a decreased beta 2-adrenergic adenylate cyclase response as well as by altered differentiation markers that include decreased loricrin and increased involucrin. Using a quantitative reverse transcription-polymerase chain reaction, we analysed the expression of beta 2-adrenergic receptor-mRNA, loricrin-mRNA, and involucrin-mRNA in the epidermis of five patients with psoriasis vulgaris. The mRNAs of the beta 2-adrenergic receptor and loricrin in the involved epidermis were significantly decreased, by 0.35-fold (P < 0.01) and 0.55-fold (P < 0.05) respectively, compared with uninvolved epidermis. In contrast, the involucrin mRNA expression of the involved epidermis was significantly increased, by 3.77-fold (P < 0.01). No significant difference in beta-actin mRNA transcripts was detected between the involved and the uninvolved epidermis. These results indicate that the altered expression of the beta 2-adrenergic receptor, loricrin, and involucrin, in the psoriatic involved epidermis, is associated with different amounts of each mRNA transcripts.