CD8+ T cell activation and differentiation in allergic asthma and the impact of cytomegalovirus serological status

Allergic asthma is a chronic inflammatory T helper 2 (Th2)-associated of CD8(+) T cells in patients. We therefore analysed activation and differentiation states of CD8(+) T cells in asymptomatic patients regarding the cytomegalovirus serological status. Memory CD8(+) T cells (CCR5(high) CD3(+)CD8(+)), memory/ effector cells (CD27(+)CD28(-)CD3(+)CD8(+)), effector cells (CD27(+)CD28(-)CD3(+)CD8(+)) and activated CD8+ T cells (CD11b(+)CD3(+)CD8(+)) were identified by flow cytometry in peripheral blood of 19 (seven cytornegalovirus (CMV)(+)/12 CMV-) patients with allergic asthma (AA) and 21 (seven CMV+/14 CMV-) healthy controls (HQ. Effector and activated CD8' T cells were significantly elevated in CMV+ HC compared to CMV- HC. There was a nonsignificant trend for reduced percentages of effector CD8'T cells in CMV+ AA (median: 10.4%, range: 4.4-33.8%) compared to CMV+ HC (median: 23.1%, range: 10.7-54.1%; P = 0.128) and in CMV- AA (median: 4.1%, range: 0.6-13.4%) compared to CMV- HC (median: 5.7%, range: 0.2-17.0%; P = 0.085). Activated CD8(+) T cells were reduced significantly in CMV+ AA (median: 17.0%, range: 6.0-29.4%) compared to CMV+ HC (median: 40.4%, range: 18.9-67.0%; P = 0.004) and showed a non-significant trend in CMV- AA (median: 15.0%, range: 2.9-24.0%) compared to CMV- HC (median: 20.2%, range: 5.8-71.0%; P = 0.060). Activated CD8(+) T cells are significantly reduced in CMV+ patients with allergic asthma. Furthermore, a trend for an impaired terminal CD8(+) T cell differentiation is observed in CMV+ and CMV- patients with asthma.