Increased entry of CD4+ T cells into the Th1 cytokine effector pathway during T-cell division following stimulation in Behcet's disease

Abstract

Objectives: To investigate the relationship between the production of Th1/Th2 cytokines and cell kinetics, cell division and proliferation in patients with Behçet's disease (BD).

Methods: Peripheral venous blood was drawn from patients with BD (n = 24; 10 patients with active and 14 patients with inactive BD) and normal subjects (n = 22). Peripheral blood mononuclear cells were separated immediately and were cultured with concanavalin A (Con A) followed by phorbol 12-myristate 13-acetate and ionomycin (PMA+Ion). Intracellular cytokine production of interferon-gamma (IFN-gamma) (Th1) and IL-4 (Th2) in CD4(+) T cells was determined by flow cytometry. Furthermore, CD4(+) T cells labelled with CFSE [5 (and 6) carboxyfluorescein diacretate, succinimidyl ester] were stimulated and the cells were analysed for entry into the cytokine production effector pathway during cell division in active BD and normal subjects.

Results: In active BD, enhanced entry into the Th1 response effector pathway of CD4(+) T cells was observed after stimulation with Con A followed by PMA+Ion. Analysis of CD4(+) T cells at an identical cell division number in response to Con A followed by PMA+Ion revealed that IFN-gamma-producing cells were increased in active BD patients compared with normal subjects. These results suggest that the Th1 response of dividing CD4(+) T cells is predominantly operating in active BD. Dividing CD4(+) T cells stimulated with Con A followed by PMA+Ion showed a phenotype of activated effector memory T cells (CD45RA(low), CD45RO(+), CD69(high)).

Conclusions: Cell kinetics play a crucial role in Th1 cell differentiation and pathophysiology in BD.