Decrease in CD4⁺CD25⁺FoxP3⁺ T_reg cells after pulmonary resection in the treatment of cavity multidrug-resistant tuberculosis

Article Outline

• Summary
• 1. Introduction
• 2. Methods
  • 2.1. Patients and controls
  • 2.2. Blood sample preparation
  • 2.3. Data acquisition and analysis
  • 2.4. Statistical analysis
• 3. Results
  • 3.1. Phenotypic analysis of CD4+ cells in patients with cavity MDR-TB pre- and postoperatively
  • 3.2. The frequency of CD4+CD25high Treg cells was increased in patients with cavity MDR-TB before surgery
  • 3.3. The proportion of CD25+FoxP3+ Treg cells in CD4+ cells was high in patients preoperatively
  • 3.4. The proportion of CD4+CD25high and CD4+CD25+FoxP3+ Treg cells decreased at 6-months postoperatively
  • 3.5. Correlation between the expression of CD4+CD25high cells and CD4+CD25+FoxP3+ cells in MDR-TB patients
• 4. Discussion
• Conflict of interest
• Acknowledgements
• References
• Copyright

Summary 

Objectives

Immune regulatory mechanisms may limit the immunopathologic condition of infection with Mycobacterium tuberculosis and suppress cellular immune responses in the host. We investigated the CD4⁺CD25⁺FoxP3⁺ circulating regulatory T cells (T_reg) in patients with cavity multidrug-resistant tuberculosis (MDR-TB) before and after surgery.

Methods

We compared the proportion of T_reg cells in 13 patients with cavity MDR-TB pre- and postoperatively and in 10 healthy control subjects by flow cytometry using three specific markers in peripheral blood lymphocytes: cell-surface CD4 and CD25 expression and intracellular FoxP3 expression.

Results

The proportion of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg was significantly higher in patients with cavity MDR-TB and at 1-month postoperatively than in healthy controls (p<0.001). The proportion of CD4⁺ and CD4⁺CD25⁻ cells was significantly lower in patients with cavity MDR-TB than in controls (p<0.001). Pre- and postoperative proportions of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg cells showed a positive correlation (r=0.878, p<0.001).

Conclusion

Circulating T_reg cells are increased in proportion in patients with cavity MDR-TB and decreased after surgery. Infection with M. tuberculosis may induce T_reg cell-surface molecular changes with increased numbers of cells.

Keywords: Multidrug-resistant tuberculosis, CD4⁺CD25⁺FoxP3⁺ T_reg, Surgery

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1. Introduction 

Tuberculosis (TB) is associated with chronic, persistent antigen stimulation in vivo to maintain a sustained immune response, which suppresses but generally fails to eradicate Mycobacterium tuberculosis (MTB) infection. Worldwide, an estimated 9.27 million cases of TB occurred in 2007.¹ Strains of M. tuberculosis that are resistant to both isoniazid and rifampin with or without resistance to other drugs have been termed multidrug-resistant TB (MDR-TB). Drug resistance information from 114 countries and the two special administrative regions (SARs) of China (i.e., Hong Kong and Macau), combined with nine epidemiological factors, revealed the global proportion of MDR-TB among new and previously treated cases to be 4.8% (95% confidence interval 4.6–6.0%). China and India carry approximately 50% of the global burden of disease.² The proportion of MDR-TB is higher than before, but the reasons are unclear. Host genetic factors may contribute to the development of MDR-TB, and incomplete and inadequate treatment is the most important factor leading to its development. MDR-TB is difficult to control by medical therapy alone, and surgery has emerged as a therapeutic option.³, ⁴

CD4⁺ and CD8⁺ T-cell-mediated immunity is the main protection against TB.⁵ CD4⁺ regulatory T cells (T_reg cells) play a key role in the control of the immune system. The most commonly used marker for T_reg cells is CD25 (interleukin 2 (IL-2) receptor α),⁶ although the recently identified transcription factor FoxP3 is more specific.⁷ The suppression function of FoxP3 mRNA expression is mediated via direct cell–cell contact or the secretion of interleukin 10 (IL-10) or transforming growth factor beta (TGF-β).⁸ The proportion of CD4⁺CD25^high T cells and levels of FoxP3 mRNA expression have both been found to be significantly higher in peripheral blood mononuclear cells (PBMCs) of patients with TB than in cells of healthy controls.⁹ Also, the proportion of CD4⁺CD25^high T cells and level of CD4⁺CD25^high FoxP3 mRNA have been found to be significantly higher in PBMCs of patients with active TB than in cells of patients with latent M. tuberculosis infection or in controls.¹⁰ In contrast, the proportion of CD4⁺CD25^high FoxP3⁺ cells is not increased,¹¹ nor is the proportion of CD4⁺CD25^high T cells decreased¹² ex vivo in patients with active TB disease.

Because immunopathology is thought to play a major role in the pathogenesis of active TB, CD4⁺CD25^high T_reg cells are considered part of the regulatory mechanisms of immunity on invasion by M. tuberculosis. Thus, we aimed to determine whether elevated T_reg cell numbers may be decreased after pulmonary resection in patients with pulmonary MDR-TB and found that the relative increase in T_reg cell ratios is significantly decreased after pulmonary resection.

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2. Methods 

2.1. Patients and controls 

Between January 2006 and December 2008, we enrolled 13 patients (nine men; mean age 50 years, range 18–70 years) undergoing surgery for pulmonary tuberculosis at The Third People's Hospital of Shantou City. These patients exhibited cavity MDR-TB concurrent infection (n=5), cavity MDR-TB concurrent aspergilloma (n=6), or lung destruction (n=2). The mean time with anti-tubercular drug therapy was 5.6 years (range 1–15 years). The indication (therapeutic vs. diagnostic) and the main clinical pathologies are shown in Table 1. Results of bacterial susceptibility testing are shown in Table 2. The main clinical symptom status of patients at postoperative month 6 (POM6) is shown in Table 3. In subject 4, the right upper lobe cavity showed concurrent aspergilloma (Figure 1, A1–A4), and the patient underwent lobectomy of the right lung in October 2008. Subject 11 showed a destroyed right lobe and underwent pulmonary resection in September 2006 (Figure 2, B1–B5).

Table 1. Indication (therapeutic vs. diagnostic) and main clinical pathology when therapeutic.

Subject	Sex	Age	Chest CT	TSTa	Sputum MTB		Clinical feature			Anti-TB drug therapy (years)	Resection type
					Smear	Culture	Fever	Cough (years)	Hemoptysis
1	M	29	(1) Type III TB; (2) RLL cavity concurrent infection	+++	+++	+	37.5–39.0°C	Cough 3 years intermittently	−	2.5	Wedge resection
2	M	53	(1) Type III TB; (2) LUL cavity	++	++	+	37.3–38.8°C	Cough 7 years intermittently	+	6	Wedge resection
3	M	18	(1) Type III TB; (2) LUL cavity concurrent infection	+++	+	+	37.0–39.0°C	Cough 1.5 years intermittently	−	1	Lobectomy
4	M	53	(1) Type III TB; (2) RUL cavity concurrent aspergilloma	++	−	+	37.5–38.5°C	Cough 5 years intermittently	−	4.5	Lobectomy
5	M	70	(1) Type III TB; (2) RUL cavity concurrent aspergilloma	++	+	+	37.2–38.6°C	Cough 6 years intermittently	+	5.5	Lobectomy
6	M	42	(1) Type III TB; (2) RLL cavity concurrent aspergilloma	++	+	+	37.5–39.5°C	Cough 10 years intermittently	+	7	Lobectomy
7	F	59	(1) Type III TB; (2) RUL cavity concurrent infection	++	+	+	37.5–39.0°C	Cough 20 years intermittently	+	7	Lobectomy
8	F	52	(1) Type III TB; (2) LUL cavity concurrent aspergilloma	++	−	+	37.2–38.5°C	Cough 5 years intermittently	+	3.5	Wedge resection
9	M	57	(1) Type III TB; (2) LUL cavity concurrent infection	++	+	+	37.5–39.5°C	Cough 4 years intermittently	−	3	Lobectomy
10	M	53	(1) Type III TB; (2) RUL cavity concurrent aspergilloma; (3) RCW abscess	++	+	+	37.2–39.5°C	Cough 3.5 years intermittently	−	3	Lobectomy
11	F	51	(1) Type III TB; (2) RL destroyed	++	+	+	37.4–39.6°C	Cough 20 years intermittently	+	15	Pulmonary resection
12	M	49	(1) Type III TB; (2) LL destroyed	+++	++	+	37.6–38.9°C	Cough 7 years intermittently	+	5.5	Pulmonary resection
13	F	62	(1) Type III TB; (2) LUL cavity concurrent aspergilloma; (3) RCW abscess	++	+	+	37.2–38.9°C	Cough 11 years intermittently	−	9.5	Lobectomy

CT, computerized tomographic scanning; TST, tuberculin skin test; MTB, Mycobacterium tuberculosis; TB, tuberculosis; RLL, right lower lobe; LUL, left upper lobe; RUL, right upper lobe; RCW, right chest wall; RL, right lobe; LL, left lobe.

Table 2. Bacterial susceptibility test results of patients preoperatively.

SM, streptomycin; INH, isoniazid ; RFP, rifampin; EMB, ethambutol; LVX, levofloxacin ; D, dipasic (pasiniazid); CTH-1321, prothionamide; CPM, capreomycin; R, resistant; S, sensitive.

Table 3. Main clinical symptom status of patients at postoperative month 6.

Subject	Sex	Age	Chest CT (comparison with preoperative)	Sputum MTB		Clinical features
				Smear	Culture	Body temperature	Cough	Hemoptysis
1	M	29	RLL cavity removal	−	−	36.9°C	No cough	−
2	M	53	LUL cavity removal	−	−	36.7°C	Cough occasionally	−
3	M	18	LUL cavity removal	−	NE	36.8°C	No cough	−
4	M	53	RUL cavity and aspergilloma removal, residue intrapulmonary air containing space with thick wall	−	−	36.7°C	Cough intermittently	−
5	M	70	RUL cavity and aspergilloma removal, residue intrapulmonary air containing space with thick wall	−	NE	36.5°C	Cough occasionally	−
6	M	42	RLL cavity and aspergilloma removal, residue intrapulmonary air containing space with thick wall	−	NE	36.9°C	NR	−
7	F	59	RUL cavity removal	−	NE	36.4°C	Cough occasionally	−
8	F	52	LUL cavity and aspergilloma removal	−	−	36.5°C	Cough occasionally	−
9	M	57	LUL cavity removal	−	−	36.8°C	Cough occasionally	−
10	M	53	RUL cavity and aspergilloma, and RCW abscess removal, pleura thickening	−	NE	36.5°C	Cough intermittently	−
11	F	51	RL removal, residue intrapulmonary air containing space with thick wall	−	−	36.8°C	Cough intermittently	−
12	M	49	LL removal, residue intrapulmonary air containing space with thick wall	−	NE	36.8°C	Cough intermittently	−
13	F	62	LUL cavity and aspergilloma and RCW abscess removal, pleura thickening	−	−	36.5°C	Cough intermittently	−

CT, computerized tomographic scanning; MTB, Mycobacterium tuberculosis; RLL, right lower lobe; LUL, left upper lobe; RUL, right upper lobe, RCW, right chest wall; RL, right lobe; LL, left lobe; NE, no examination; NR, no record.

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• Figure 1. 

  Computed tomography (CT) scan of a 53-year-old man with multidrug-resistant tuberculosis. Preoperative CT scan of the chest in October 2008 (A1, A2): right upper lung cavity shows concurrent aspergilloma. Postoperative CT scan of the chest in April 2009 (postoperative month 6: A3, A4): focus of infection was removed and residual intrapulmonary air-containing space with thick wall.

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• Figure 2. 

  Computed tomography (CT) scan of a 51-year-old female with multidrug-resistant tuberculosis. Preoperative CT scan of the chest in September 2006 (B1, B2, B3): right lung destroyed and collapsed, the left lung showing scale-up complications. Postoperative CT scan of the chest in May 2007 (postoperative month 6: B4, B5): focus of infection was removed and residual intrapulmonary air-containing space with thick wall.

Peripheral blood was obtained from patients before and 1 and 6 months after surgery. We recruited 10 healthy volunteers (seven men; mean age 42 years, range 25–63 years). All patients underwent postoperative individualized chemotherapy to ensure long-term cure. All subjects were HIV-negative. The study protocol was approved by our institutional review board for human studies, and informed consent was obtained from all subjects.

2.2. Blood sample preparation 

Whole blood was collected in 12×75-mm plastic tubes containing anti-coagulant (EDTA-K2) and immediately underwent cellular staining. Whole blood (100μl) was aliquoted (per tube) along with 20μl of appropriate test antibody or respective isotype control for three color tests: fluorescein isothiocyanate (FITC) anti-FoxP3 (clone PCH101, CAT.11-4766, eBioscience, San Diego, CA, USA), phycoerythrin peridinin chlorophyll protein (PerCP) anti-CD4 (clone RPA-T4, CAT.300528, Biolegend, San Diego, CA, USA), and phycoerythrin (PE) anti-CD25 (clone B1.49.9, CAT.IM0479u, Beckman Coulter, Los Angeles, CA, USA). The following isotype control antibodies were used: FITC rat IgG2b (κ, CAT.11-4031, eBioscience), PerCP mouse IgG1 (clone MOPC-21, CAT.400145, Biolegend), PE mouse IgG1 (clone 679.1 Mc7, CAT.IM0670u, Beckman Coulter). After surface staining for 30min in the dark at room temperature, erythrocytes were lysed, and cells were fixed with the use of immuno-prep reagents (Beckman Coulter) using a Q-prep Immunology workstation (Beckman Coulter). Surface-stained cells then underwent intracellular FoxP3 staining with use of the anti-FoxP3 staining kit according to the manufacturer's recommendations.

2.3. Data acquisition and analysis 

Listmode data were acquired on the Epics XL flow cytometer (Beckman Coulter) and were analyzed using EXPO32 software (Beckman Coulter). The lymphocyte gate was generated by use of forward and side-angle scattered (FSC/SSC) light window leukogating to analyze the cell-surface antigens CD4 and CD25. To determine the proportion of T_reg cells, CD4⁺ T cells were gated by plotting forward versus side scatter to analyze the intracytoplasm antigen against FoxP3.

2.4. Statistical analysis 

Values are presented as mean±standard deviation (SD). All results were analyzed using SPSS v 13.0 (SPSS Inc., Chicago, IL, USA). Differences in means between patients and controls were analyzed by one-way analysis of variance (ANOVA); differences in means for patients pre- and postoperatively were analyzed by paired-samples t-test and correlation was examined by Spearman rank correlation analysis. A p-value of <0.05 was considered statistically significant.

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3. Results 

To determine the frequency of T_reg cells, gated lymphocytes and CD4⁺ cells were analyzed for expression of CD4, CD25 (representative plots in Figure 3, A1–D1), and FoxP3 (representative plots in Figure 4, A2–D2).

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• Figure 3. 

  Flow cytometry analyses of CD25^+high expression by CD4⁺ T cells. The lymphocyte gate was generated by use of forward and side-angle scattered light window (FSC/SSC) dot plots (A1). Representative flow cytometry results of surface CD4 and CD25 expression on peripheral blood lymphocytes from a patient with active TB preoperatively (B1), at postoperative month 1 (POM1; C1), and at postoperative month 6 (POM6; D1). L1: CD4⁻CD25⁺ cells; L2: CD4⁺CD25⁺ cells; L3: CD4⁻CD25⁻ cells; L4: CD4⁻CD25⁺ cells; M1: CD4⁻CD25^+high cells; M2: CD4⁺CD25^+high cells; M3: CD4⁻CD25^−high cells; M4: CD4⁻CD25⁺ cells.

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• Figure 4. 

  Flow cytometry analysis of intracellular FoxP3 and surface CD25 expression on CD4⁺ T cells in patients with tuberculosis (TB). The CD4⁺ T cells are shown gated (A2). Representative flow cytometry results of intracellular FoxP3 and surface CD25 expression on peripheral blood lymphocytes from a patient with active TB preoperatively (B2), at postoperative month 1 (POM1; C2), and at postoperative month 6 (POM6; D2). G1:CD4⁺CD25⁺FoxP3⁻ cells; G2:CD4⁺CD25⁺FoxP3⁺ cells; G3:CD4⁺CD25⁻ FoxP3⁻ cells; G4:CD4⁺CD25⁻ FoxP3⁺ cells.

3.1. Phenotypic analysis of CD4⁺ cells in patients with cavity MDR-TB pre- and postoperatively 

On flow cytometry, as compared with healthy controls, patients with MDR-TB showed significantly decreased proportions of CD4⁺ T cells preoperatively (31.85±1.03% vs. 38.91±2.10%); this was increased postoperatively compared with preoperatively (postoperative month 1 (POM1) 39.59±2.26%, postoperative month 6 (POM6) 39.02±1.47%) (p<0.001). Also, the proportion of CD4⁺CD25⁺ cells was significantly increased preoperatively (12.28±1.96% vs. 8.36±1.54% for controls) and decreased postoperatively compared with preoperatively (POM1 9.91±1.50%, POM6 9.23±0.78%) (p<0.001). However, the proportion of CD4⁺CD25⁻ cells was significantly decreased preoperatively (19.56±2.78% vs. 30.55±2.82% for controls) and increased postoperatively compared with preoperatively (POM1 29.68±3.26%, POM6 29.78±1.56%) (p<0.001) (Figure 5).

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• Figure 5. 

  Percentage of CD4⁺ cells, CD4⁺CD25⁺ cells, and CD4⁺CD25⁻ cells in non-infected control subjects (CTRL; n=10), and in patients with cavity MDR-TB (n=13) pre- and postoperatively: preoperative, postoperative month 1 (POM1), and postoperative month 6 (POM6).

3.2. The frequency of CD4⁺CD25^high T_reg cells was increased in patients with cavity MDR-TB before surgery 

The frequency of CD4⁺CD25^high T_reg cells was determined on flow cytometry. The lymphocytes were gated to analyze CD4⁺CD25^high T_reg cells. As compared with controls, patients with MDR-TB showed significantly increased proportions of CD4⁺CD25^high T_reg cells both preoperatively and at 1-month postoperatively (7.00±1.10%, POM1 6.25±1.23% vs. 4.16±1.02% for controls) (p<0.001), with no significant increase in proportion of CD4⁺CD25^high T_reg cells at 6-months postoperatively compared with healthy controls (p>0.05) (Figure 6).

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• Figure 6. 

  The proportion of CD4⁺CD25⁺ cells that are CD25^high in non-infected controls (CTRL; n=10) and patients with cavity MDR-TB before and after surgery (n=13): preoperative, postoperative month 1 (POM1), and postoperative month 6 (POM6). Horizontal bars indicate median values.

3.3. The proportion of CD25⁺FoxP3⁺ T_reg cells in CD4⁺ cells was high in patients preoperatively 

Since FoxP3 transcription factor is considered the most reliable molecular marker of CD4⁺CD25^high T_reg cells, we investigated the intracellular expression of FoxP3 in CD4⁺CD25⁺ T cells. FoxP3 expression was significantly higher in patients preoperatively and at 1-month postoperatively as compared with healthy controls (7.45±1.19%, POM1 6.74±1.03% vs. 4.50±1.03%) (p<0.001). However, at 6-months postoperatively, the proportion of CD4⁺CD25⁺FoxP3⁺ T_reg cells was similar between healthy subjects and patients (p>0.05) (Figure 7).

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• Figure 7. 

  The proportion of CD4⁺CD25⁺FoxP3⁺ T_reg cells among the CD4⁺ cells measured by flow cytometry in 10 non-infected control subjects (CTRL) and 13 patients with cavity MDR-TB pre- and postoperatively: preoperative, postoperative month 1 (POM1), and postoperative month 6 (POM6). Horizontal bars indicate median values.

3.4. The proportion of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg cells decreased at 6-months postoperatively 

We investigated the proportion of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg cells pre- and postoperatively. The proportion of both CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg cells in patients with TB was significantly lower at 6-months postoperatively than preoperatively (p<0.001), with no significant difference between preoperative and 1-month postoperative proportions (p>0.05) (Figure 8, Figure 9).

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• Figure 8. 

  The proportion of the CD4⁺CD25⁺ cells that are CD25^high in patients with cavity MDR-TB pre- and postoperatively (n=13): preoperative, postoperative month 1 (POM1), and postoperative month 6 (POM6).

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• Figure 9. 

  The proportion of the CD4⁺CD25⁺FoxP3⁺cells in patients with cavity MDR-TB pre- and postoperatively (n=13): preoperative, postoperative month 1 (POM1), and postoperative month 6 (POM6).

3.5. Correlation between the expression of CD4⁺CD25^high cells and CD4⁺CD25⁺FoxP3⁺ cells in MDR-TB patients 

We analyzed the correlation between the proportion of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ cells in peripheral blood in patients with active cavity MDR-TB and found a significant correlation (r=0.878; p<0.001; using data from all subjects) (Figure 10).

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• Figure 10. 

  Correlation between the proportion of CD4⁺CD25^+high cells and CD4⁺CD25⁺FoxP3⁺ cells (r=0.878, p<0.001).

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4. Discussion 

The estimated worldwide incidence of TB and MDR-TB continues to increase. Despite the success of medical therapy alone, resistance to drugs and complications of the disease still present a challenge.¹³ The host response to infection with M. tuberculosis involves the cellular immune system of T-helper 1-type interferon-γ-secreting CD4 and CD8 effector T cells.¹⁴ This response helps to limit bacterial replication and dissemination in vivo and causes important immunopathologic features such as inflammation, but in general fails to eradicate the infection. We suggested that the immune system has regulatory mechanisms to suppress the effector response to persistent antigens. Indeed, we found the proportion of CD4⁺CD25^high and CD4⁺CD25⁺FoxP3⁺ T_reg cells significantly higher in patients with cavity MDR-TB and at 1-month postoperatively than in healthy controls. Also, the proportion of CD4⁺ and CD4⁺CD25⁻ cells was significantly lower in patients with cavity MDR-TB than in healthy controls.

Increasingly, FoxP3-expressing T_reg cells are considered critical for suppressing immune responses to self-antigens and preventing autoimmunity and for regulating immunity to foreign antigens, especially those derived from pathogens that establish persistent infections.¹⁵ T_reg cells were found to prevent eradication of tubercle bacilli by suppressing an otherwise efficient CD4⁺ T-cell response.¹⁶ To investigate T_reg cells, we used the markers CD4⁺ and high levels of cell-surface CD25 expression and intracellular FoxP3 expression. The expression of CD4⁺CD25^high cells and CD4⁺CD25⁺FoxP3⁺ cells was significantly increased in peripheral blood of patients with cavity MDR-TB, which is in agreement with the report by Guyot-Revol et al.⁹ Previously, the proportion of CD4⁺CD25^high T cells and CD4⁺CD25^high FoxP3 cells was found significantly higher in PBMCs of patients with active TB as compared with those with latent TB infection and controls, with no difference between those with latent infection and healthy controls.¹⁰ However, whether T_reg cells decreased in number after cure of active TB was unknown. Therefore, we analyzed the expression of CD4⁺CD25^high cells and CD4⁺CD25⁺FoxP3⁺ cells at 1 and 6 months after surgery in patients with cavity MDR-TB. The proportion of CD4⁺CD25^high cells and CD4⁺CD25⁺FoxP3⁺ cells was significantly decreased in peripheral blood at 6-months postoperatively as compared with preoperatively and 1-month postoperatively, and did not significantly differ from that in healthy controls. One possible mechanism for T_reg cells suppressing anti-M. tuberculosis immunity is that CD4⁺CD25⁺FoxP3⁺ regulatory T cells produce the cytokine TGF-β and/or IL-10, which depresses interferon-gamma (IFN-γ) production.¹⁷ Neutralization of TGF-β and IL-10 each result in an increase in elicited IFN-γ.¹⁸ CD4⁺CD25⁺FoxP3⁺ T_reg expansion in TB patients may contribute to suppress M. tuberculosis immune responses by inhibiting IFN-γ production of PBMCs in patients with active TB or pleural fluid mononuclear cells in patients with tuberculous pleurisy.¹⁹ However, the mechanisms by which T_reg cells increase in number are incompletely understood and need further research. The bacterial burden may, in part, induce the increase in T_reg cells.

MDR-TB is caused by M. tuberculosis strains resistant to at least rifampin and isoniazid. Because failure of medical treatment leads to a dismal prognosis, surgical resection has been advocated to supplement medical therapy in some patients with tracheal or bronchial stenosis, aspergillomas growing on cavitated lesions, bronchiectasis, destroyed lungs, or massive hemoptysis. Our patients showed a good prognosis after surgery, which suggests that the immunity function recovered after surgery. Because morbidity and mortality rates are acceptable, surgical intervention can be considered safe and effective in patients with pulmonary TB.

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Conflict of interest 

No conflict of interest to declare.

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Acknowledgements 

This study was supported by the 211 Project of Guangdong Province (Mechanism and Prevention of New Emergence Infection) and the Science and Technology Planning Project of Shantou (Prognostic Evaluation of Pulmonary Resection in the Treatment of Cavity Multidrug-resistant Tuberculosis (2009–70)), Guangdong Province, China.

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