FIBROBLAST FUNCTION IN PSORIATIC-ARTHRITIS .2. INCREASED EXPRESSION OF BETA-PLATELET-DERIVED GROWTH-FACTOR RECEPTORS AND INCREASED PRODUCTION OF GROWTH-FACTOR AND CYTOKINES

Objective. The main objective was to investigate the expression of pla telet derived growth factor (PDGF) receptors, and production of growth factors and cytokines from psoriatic skin and synovium derived fibrob lasts. Methods. Fibroblast cultures were established from normal and p soriatic skin and synovium. Confluent cultures of fibroblasts were use d for a receptor binding assay for PDGF, and then extracts were run on Western blot. The amount of immunoreactive A and B chain peptides pre sent was determined with specific A or B chain antisera. production of interleukin 1 beta and PDGF-beta was accomplished by neutralization w ith the use of commercially available antisera. A functional assay was used to measure transforming growth factor-beta (TGF-beta). Results. There was an increased expression of the beta PDGF receptor in the pso riatic fibroblasts. Interleukin 1 beta and PDGF-beta production by pso riatic fibroblasts was also increased. However, TGF-beta production wa s similar in normal and psoriatic fibroblasts. Conclusion. Our data de monstrate an increased expression of beta PDGF receptor, and productio n of IL-1 beta and PDGF by psoriatic fibroblasts. The findings provide further support for an active role of this cell Line in the pathogene sis of psoriasis and psoriatic arthritis.