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

SummaryObjectives and methodsDespite 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-2Rα (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.ResultsThe 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 lower 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).ConclusionDiminished percentage of peripheral CD4+ T-lymphocytes expressing IL-2Rα is associated with chronic relapsing brucellosis.