Peripheral CD25 positive T lymphocytes with biased T cell receptor V gene usage in autoimmune endogenous posterior uveitis

Abstract
Aims—To determine T cell receptor (TCR) Vβ gene usage in peripheral blood T lymphocytes of patients with endogenous posterior uveitis (EPU). If biased TCR variable (V) gene usage occurs in this autoimmune disease, it should be detectable in immune activated peripheral blood T cells in vivo. Methods—Relative proportions of each Vβ gene family expressed in total peripheral blood lymphocytes (PBL) and in vivo activated (CD25+) T cells from patients with EPU and controls were determined using the anchored polymerase chain reaction (anchored PCR) in conjunction with a novel hybridisation assay. The TCR Vβ repertoires seen in these cell populations were then compared. Results—Vβ1 usage within the CD25+ lymphocytes of patients with EPU was substantially elevated (mean ± SD 15 ±9%) compared with control CD25+ cells (3.3 ±2.4%). Conclusions—By contrasting the repertoires of these cell populations, biased TCR Vβ gene usage was detected in patients with EPU, namely increased usage of Vβ1 in CD25+ T cells from peripheral blood of these patients. This approach of directly analysing the activated T cells in blood, using bulk PBL as an internal control, has wide applicability where specific T cell subpopulations are thought to play an important aetiopathological role.