Volume and differentiation of sebaceous glands in psoriasis

Psoriasis is a chronic inflammatory skin disease. Microscopic findings in the past have revealed some degree of atrophy of the sebaceous gland in psoriasis and psoriatic alopecia. In order to investigate the possible role of sebaceous glands in psoriasis, skin specimens from psoriasis-involved and healthy looking skin of 14 patients were obtained, and histological and stereological analysis were performed. The method of stereology provides the quantification of 3-dimensional structures ex vivo; thus it was possible to estimate and, for the first time, calculate the volume of sebaceous glands in psoriasis. The results revealed a significant reduction of the number and volume of sebaceous glands in the lesional compared to the non-lesional skin. Furthermore, skin specimens from psoriasis-involved and healthy looking skin of another 14 patients were obtained in order to perform immunohistochemical analysis. The differentiation stages of sebocytes were compared between the two groups. It could be shown that the sebocytes in psoriasis do not differentiate properly. These findings bring the sebaceous gland -for the first time- to the front of the research in psoriasis.