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Diminished percentage of CD4+ T-lymphocytes expressing interleukine-2 receptor alpha in chronic brucellosis
Panagiotis Skendros1, Panagiota Boura, Dimitrios Chrisagis
1Clinical Immunology Unit, 2nd Department of Internal Medicine, Aristotle University, Konstantinoupoleos 49, 54642 Thessaloniki, Greece.
Insights
Diminished CD4+ T-cells expressing IL-2 receptor alpha (CD25) are linked to chronic brucellosis. This finding offers insights into immune responses in persistent Brucella infections.
Area of Science:
- Immunology
- Infectious Diseases
- T-cell Biology
Background:
- Brucellosis often leads to chronic disease despite treatment, with altered immune responses.
- Impaired T-helper 1 (Th1) cytokine production, including reduced IL-2, is noted in chronic brucellosis.
- The role of IL-2 receptor alpha (CD25) in brucellosis outcomes requires further investigation.
Purpose of the Study:
- To evaluate the expression of IL-2 receptor alpha (CD25) on peripheral CD4+ T-lymphocytes in acute and chronic brucellosis patients.
- To assess the association between CD25 expression on T-cells and disease chronicity or relapse in brucellosis.
- To analyze T-lymphocyte subsets (CD3+, CD4+, CD8+) in different brucellosis patient groups.
Main Methods:
- Flow cytometry was used to quantify ex vivo and PHA-induced CD4+ T-cells expressing CD25.
- Peripheral blood samples were analyzed from acute brucellosis patients (n=13), chronic brucellosis patients (n=22), "clinically cured" subjects (n=11), and healthy controls (n=15).
- T-lymphocyte subsets (CD3+, CD4+, CD8+) were simultaneously measured.
Main Results:
- Ex vivo CD4+/CD25+ T-cells were higher in acute brucellosis patients compared to cured subjects and controls.
- Chronic brucellosis patients showed significantly lower ex vivo and PHA-induced CD4+/CD25+ T-cells compared to acute patients.
- Increased CD8+ T-lymphocytes were observed in chronic and relapsing brucellosis patients compared to acute patients.
Conclusions:
- A diminished percentage of peripheral CD4+ T-lymphocytes expressing IL-2 receptor alpha (CD25) is associated with chronic relapsing brucellosis.
- These findings suggest a potential role for CD25 expression in differentiating disease outcomes in brucellosis.
- The study highlights altered T-cell dynamics in chronic brucellosis, particularly in relapsing forms.
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 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).
Conclusion:
Diminished percentage of peripheral CD4+ T-lymphocytes expressing IL-2R alpha is associated with chronic relapsing brucellosis.
