Keratinization, absence of granular layer, and depositation of antibodies and complement components in the stratum corneum. Most notable is the hyperproliferation of keratinocytes in the epidermis. These keratinocytes exhibit an increased mitotic rate and have ten times the turnover rate of normal keratinocytes. There is also an infiltration of CD4+ T lymphocytes, monocytes and neutrophils into the epidermis. Recently there has been much debate over whether psoriasis is mediated by an autoimmune process. The disease affects roughly two percen ....