Phenotypic Characteristics of CD8(bright) T Cells in Behcet's Uveitis

ABSTRACT

PURPOSE: To determine the phenotypic characteristics of peripheral CD8(bright) T cells. METHODS: Forty patients with Behcet's disease (BD) with uveitis (active 20; inactive 20) and 20 healthy controls were recruited in this study. Phenotypic analysis of fresh PBMCs was performed using anti-CD8 mAb and anti-CD56 mAb in conjunction with a three- or four-color immunofluorescence tests for the expression levels of the following molecules CD11b, CD27, CD45RA, CD45RO, CD62L, CD94, NKG2D, and HLA-DR. RESULTS: CD27 and CD62L were down-regulated on peripheral CD8(bright) T cells in patients with active Behcet's uveitis in contrast to the up-regulation of CD11b and HLA-DR. These phenotypic natures were remarkable in the CD56+ subsets. CD45RA(dim)CD45RO- phenotypes were expanded in peripheral CD8(bright)CD56+ T cells according to the disease activity. Interestingly, in active Behcet's uveitis, CD94 was up-regulated on peripheral CD8(bright)CD56+ T cells in BD in contrast to the down-regulation of NKG2D compared with the normal controls. CONCLUSIONS: CD8(bright)CD56+ T cells are characterized by activated effector phenotypes with functional NK receptors and they may play immunopathogenic roles in Behcet's uveitis.