SELECTIVE AMPLIFICATION OF T-CELL RECEPTOR VARIABLE REGION SPECIES ISDEMONSTRABLE BUT NOT ESSENTIAL IN EARLY LESIONS OF PSORIASIS-VULGARIS- ANALYSIS BY ANCHORED POLYMERASE CHAIN-REACTION AND HYPERVARIABLE REGION SIZE SPECTRATYPING

Several groups have investigated the role of T cells in the pathogenes is of psoriasis by determination of T-cell receptor (TCR) B-chain vari able (V) region usage, both in chronic plaque (psoriasis vulgaris) and guttate forms, with various results, Because there are no data on TCR expression in early psoriasis vulgaris, when specific cellular immune events may be expected to be most pronounced, we have analyzed early lesions (less than 3 wk old) of ten patients, with highly reproducible results. We have developed a highly controlled anchored polymerase ch ain reaction (PCR) method in which TCR beta chain species are all ampl ified with the same primer pair and products are quantified by dot blo t hybridization with BV family-specific oligonucleotide probes, Overex pression of certain TCR BV genes was observed in the majority of lesio nal biopsies, but in samples in which the expanded BV family formed mo re than 10% of total lesional BV (half of the samples analyzed), BV2 a nd BV6 predominated, The consistency of overexpression of these BV spe cies between patients was much less than in previous studies of TCRBV usage in established chronic plaque psoriasis lesions. Complementarity -determining region 3 (CDR3) size spectratyping demonstrated evidence for selective clonal T cell accumulation in less than half of the lesi onal samples showing BV expansion, These results indicate that selecti ve amplification of TCRBV species occurs in early psoriasis vulgaris b ut is not essential to the pathogenic process and may be more importan t in the maintenance or expansion of chronic lesions.