Selection of conserved TCR VDJ rearrangements in chronic psoriatic plaquesindicates a common antigen in psoriasis vulgaris

Psoriasis vulgaris is a common HLA-associated inflammatory skin disease. Al though its etiology is still unknown, it is thought to involve T cell-media ted inflammatory mechanisms. In examining the lesional psoriatic TCR beta c hain (TCRB) usage in a pair of identical twins concordant for psoriasis, we observed repetitive TCR VDJ rearrangements which indicated antigen-specifi c oligoclonal T cell expansion. Several of these TCRB rearrangements were i dentical or highly homologous in the amino acid composition of the compleme ntarity determining region 3 (CDR3), suggesting that T cells with these TCR might be important for disease manifestation. This conclusion was strength ened by TCR analysis of other psoriasis patients. Several repetitive lesion al TCRB rearrangements were found that were similar to the conserved CDR3 s een in the twins. Since TCR antigen specificity is largely determined by th e beta chain CDR3, selection of T cells with conserved TCRB CDR3 motifs cou ld indicate the presence of a common antigen as a major target of the lesio nal psoriatic immune response.