Quantitative analysis of T-cell receptor beta variable-gene usage in cutaneous late-phase reactions: Implications for T-lymphocyte recruitment in cutaneous inflammation

To determine if functionally distinct T-lymphocyte (T cell) subsets accumul ate in late-phase immunoglobulin E-mediated reactions (LPR), we quantitativ ely analyzed the immunophenotype and the T-cell receptor beta variable-gene (V beta) repertoire of T cells in cutaneous LPR. Peripheral blood and skin biopsies were obtained 6 or 24 h after sensitive subjects were challenged with intradermal injections of grass pollen allergen (Ag) and control (C) s olution. The frequency of cells expressing CD3, CD4, CD8, CD45RO, and CD25/ mm(2) was determined by immunohistochemistry in nine subjects. V beta usage was assessed by reverse transcription-PCR in five of nine subjects. A sign ificantly greater frequency of CD3(+) and CD45RO(+) (memory) T cells was de tected in Ag sites than in C sites at 24 h after challenge hut not at 6 h. The frequency of activated (CD25(+)) and helper (CD4(+)) T cells appeared t o be increased in Ag sites as well, though not significantly. V beta 6 was the most commonly expressed V beta detected in Ag sites, but it was also de tected in accompanying C sites. V beta 2 was the most commonly expressed V beta detected in C sites. Sequence analysis in one case revealed V beta exp ression in a 6-h Ag site to be essentially polyclonal. Our findings suggest that memory T cells with V beta expression similar to that in normal skin accumulate in developing cutaneous LPR. The limited usage of V beta suggest s a preferential recruitment or retention of reactive T cells from an endog enous subset of skin-homing T cells with its own skewed V beta repertoire.