Acne vulgaris: proliferative cells in sebaceous glands.

The proliferative activity of sebaceous glands of uninvolved skin from acne patients was analysed by means of ³H-thymidine autoradiography and by planimetry. Twelve specimens of normal skin from the back (with thirty-five glands) and two specimens from the face (with six glands) were analysed. Labelling indices and planimetric values were determined separately for the two portions within each gland: the differentiating cell pool with germinative cells and large lipid cells; and the undifferentiated cell pool with multilayered cells. The germinative cells of the differentiating cell pool on the back and face of patients with acne showed a significantly greater labelling index than in control subjects. The undifferentiated cell pool, although having a higher labelling index than the differentiating cell pool, was similar both in acne patients and in controls. Planimetry confirmed that the sebaceous glands of patients are much larger than those of normal subjects. Therefore, the known increase in sebum excretion in acne patients is a result of two factors—an increase in lipid cell production and an increase in sebaceous gland size. [ABSTRACT FROM AUTHOR]