Diminished percentage of CD4+ T-lymphocytes expressing interleukine-2 receptor alpha in chronic brucellosis

Objectives and methods: Despite the treatment, a considerable proportion of brucellosis patients develop chronic disease, characterized by atypical clinical picture and/or relapses. Th1 cytokines are critical for the clearance of Brucella infection and diminished production of IL-2 in response to PHA, has been described in chronic brucellosis. In order to investigate the role of IL-2R alpha (CD25) in disease outcome, we evaluated the ex vivo and PHA-induced percentage of peripheral CD4+ T-lymphocytes expressing CD25 in 13 acute brucellosis patients (AB), 22 chronic brucellosis patients (CB), 11 clinically cured subjects and 15 healthy volunteers (controls). Simultaneously, CD3+, CD4+ and CD8+ T-lymphocytes subsets were measured. Results: The ex vivo percentage of CD4+ /CD25+ T-cells was significantly higher in AB patients compared to clinically cured subjects (p = 0.005) and controls (p = 0.006). By contrast, CD4+/CD25+ T-cells were significantly tower in CB patients (p = 0.001). T-lymphocytes subsets did not significantly differ between the groups. After PHA stimulation, CD4+ /CD25+ T-cells remained significantly Lower in CB and specifically in the relapsing form of chronic disease compared to AB (p = 0.044, 0.023). Additionally, CD8+ T-Lymphocytes were found to be significantly increased in CB and mainly in the relapsing subgroup of CB patients compared to AB (p = 0.044, 0. 011 Conclusion: Diminished percentage of peripheral CD4+ T-lymphocytes expressing IL-2R alpha is associated with chronic relapsing brucellosis. (C) 2006 The British Infection Society. Published by Elsevier Ltd. All rights reserved.