RT-PCR TOPOGRAPHY OF CHRONIC PSORIASIS SKIN BASED ON ANALYSIS OF T-CELL RECEPTOR-B VARIABLE REGION GENE USAGE

Psoriasis is a hyperproliferative inflammatory disease and 70% of pati ents develop a chronic plaque form. The pathogenesis of psoriasis is n ot known but evidence exists that T cells play a crucial role. The T c ell V-gene receptor repertoire from psoriasis skin (different layers) was compared with peripheral blood T cells by employing RNA polymerase chain reaction (PCR) amplification. T cell receptor (TCR) BV 5.1, 11, 12, 13.1 and 16 were utilized to a significantly higher degree in are as close to the basal layers when compared to CD4+, CD8+ or unfraction ated blood T cells from the same patients, whereas only BV11 and 13.1 genes of T cells from deeper layers of the dermis showed such a skewed usage. No biased usage of TCRBV genes was observed in superficial lay ers or in whole skin. Furthermore, T cell receptor junctional diversit y analysed by high resolution gel electrophoresis showed skin psoriati c T cells to be poly- or oligoclonal. In conclusion, we show that TCRB V gene usage from different layers of psoriatic skin has a different p attern compared with the corresponding gene usage in circulating perip heral blood T cells. This pattern may implicate possible skin-associat ed antigen or superantigens activating a limited number of T cells in areas of skin close to basal layers, which in turn could promote kerat inocyte proliferation.