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Published on: June 22, 2016
Circulating CD4+ CD25 high FoxP3+ T cells vary in different clinical forms of leprosy
Enas A S Attia1, Marwa Abdallah, Abeer A Saad
1Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Ain Shams University, Cairo, Egypt. annosah74@hotmail.com
Insights
Regulatory T cells (T-regs) are elevated in leprosy patients, particularly in tuberculoid (TT) forms. This suggests intact T-regs activity may benefit leprosy patients, despite lower frequencies in lepromatous (LL) and ENL forms.
Area of Science:
- Immunology
- Infectious Diseases
- Cell Biology
Background:
- Regulatory T cells (T-regs), characterized by CD4(+) CD25(high) FoxP3(+) expression, are known to increase in chronic infections.
- The role of T-regs in Mycobacterium leprae infection, the causative agent of leprosy, remains to be fully elucidated.
- Understanding T-reg dynamics is crucial for comprehending immune responses in leprosy.
Purpose of the Study:
- To investigate the frequency and FoxP3 expression of circulating T-regs in leprosy patients.
- To determine the association between T-reg levels and different clinical forms of leprosy, including tuberculoid (TT), borderline (BT, BB, BL), lepromatous (LL), and erythema nodosum leprosum (ENL).
- To explore the potential role of T-regs in the immune pathogenesis of leprosy.
Main Methods:
- Flow cytometry was employed to quantify the frequency and FoxP3 expression of T-regs.
- A cohort of 38 leprosy patients, categorized into four groups (TT, borderline, LL, ENL), and 38 healthy controls were analyzed.
- Circulating T-regs were assessed for their percentage and FoxP3 expression levels.
Main Results:
- T-reg frequency and FoxP3 expression were significantly elevated in leprosy patients compared to healthy controls, particularly in the tuberculoid (TT) group.
- T-reg frequency varied significantly across the disease groups, being highest in TT and lowest in ENL.
- FoxP3 expression on T-regs was notably higher in ENL patients compared to controls, though not significantly different among the patient groups.
Conclusions:
- The frequency and suppressive marker (FoxP3) of circulating T-regs are elevated in tuberculoid (TT) leprosy.
- Lepromatous (LL) and erythema nodosum leprosum (ENL) patients exhibit lower T-reg frequencies, with ENL showing higher FoxP3 expression, suggesting immune hyper-activation.
- Intact T-regs activity may be beneficial rather than detrimental to leprosy patients, indicating a potentially protective role in disease management.
Background:
CD4(+) CD25(high) FoxP3(+) regulatory T cells (T-regs) were reported to increase in chronic infections. We aimed at studying their frequency in leprosy to investigate their role during Mycobacterium leprae infection.
Methods:
Using flow cytometry, the frequency and FoxP3 expression of circulating T-regs was assessed in 38 leprosy patients and 38 healthy controls. Patients were divided into; group I tuberculoid (TT), group II borderline cases [borderline tuberculoid (BT), borderline (BB), and borderline lepromatous (BL)], group III lepromatous (LL), and group IV erythema nodosum leprosum (ENL).
Results:
Mean T-regs% and FoxP3 expression were significantly elevated in patients (particularly TT) compared to controls (3.8 ± 2.5% vs. 2.5 ± 0.8% and 78.8 ± 56.2% vs. 55.8 ± 15.7%, respectively) (P < 0.05). Comparing the four disease groups, T-regs% was significantly different (median 5.3% in group I, 3.4% in group II, 2.8% in group III, and 1.2% in group IV; P = 0.005). FoxP3% on T-regs was not significantly different between them [median 71.5% in TT, 62.3% in borderline categories, 67.75% in LL, and 85.75% in ENL; P = 0.149). Notably FoxP3 expression was significantly higher in ENL than controls (P = 0.011).
Conclusion:
The frequency and suppressive marker of circulating T-regs are elevated in TT patients. Patients with LL and ENL express significantly lower frequency of T-regs and higher FoxP3 expression (in ENL), consistent with disease progression and immune hyper-activation in these disease categories. Thus, rather than being detrimental to immunity, intact T-regs activity may be beneficial to leprosy patients.
