ESTABLISHMENT AND CHARACTERIZATION OF A NOVEL HUMAN PROMONOCYTIC CELL-LINE FROM PERIPHERAL-BLOOD OF A PATIENT WITH PSORIASIS

Human monocyte/macrophage lineages have unique phagocytic and immune-r egulatory functions. We established a promonocytic cell line from the peripheral blood of a patient with psoriasis vulgaris. The newly estab lished cells, termed YAP cells, grew in a suspension culture. In Wrigh t-Giemsa-stained preparations, YAP cells were round or polygonal in sh ape. Transmission electron microscopy showed that the cells had clear nuclei with well-defined nucleoli. There were frequent mitochondria, a relatively abundant endoplasmic reticulum profile, free ribosomes and an occasional Golgi apparatus. Cytochemical studies showed a positive reaction for a-naphthyl butyrate esterase, which was completely inhib ited by sodium fluoride, a diffuse positive reaction for periodic acid -Schiff, and a negative result for alkaline phosphatase and peroxidase . A large population of YAP cells reacted with the CD4, CD11b, CD25 an d CD33 surface markers, but not with CD2, CD3, CD8 or CD19. We also fo und that YAP cells produced considerable amounts of TNF alpha, which w as detected in the culture supernatant when the cells were treated wit h 1 ng/ml 12-O-tetradecanoylphorbol-13-acetate (TPA). Chromosome analy ses showed that YAP cells contained a variety of marker chromosomes. I t should be stressed that YAP cells were derived from a patient with a non-neoplastic disorder, whereas most monocytic cell lines previously reported are of malignant origin. This newly established cell line mi ght be valuable for studying the pathogenesis of psoriasis, especially the role of monocytes/macrophages in the aetiology of the disease.