Altered CD8(+) T cell frequency and function in tuberculous lymphadenitis

Characterization of peripheral cytokine-secreting cells responses in HIV/TB co-infection

Background

Currently the responses of peripheral cytokine-secreting cells in the natural course of human immunodeficiency virus (HIV) and tuberculosis (TB) co-infection haven't been fully elucidated.

Methods

The function of peripheral proinflammatory, regulatory and cytotoxic cytokine-secreting cells were investigated by direct intracellular cytokine staining (ICS) and flow cytometry, additionally, the absolute numbers of different cytokine-secreting cells were measured among patients with HIV/TB co-infection (HT group), and compared them with the healthy controls (HC group), patients with TB (TB group) and patients with HIV infection (HIV group). After one week's anti-TB treatment, the changes of the percentages of cytokine-secreting cells were further evaluated in TB and HT groups.

Results

Totally 26 individuals in the HC group, 51 in the TB group, 26 in the HIV group and 29 in the HT group were enrolled. The HT. HT group exhibited significantly lower absolute numbers of IFN-γ⁺CD4⁺, IFN-γ⁺CD8⁺, TNF-α⁺CD4⁺, IL17A⁺CD4⁺ T cells and TNF-α⁺CD14⁺ monocytes than the TB and HIV groups. Compared with the TB group, the percentages of CD8⁺ T cells secreting IFN-γ and perforin (p=0.010; p=0.043) were significantly lower among the HT group. Compared with the HIV group, the percentages of CD4⁺, CD8⁺ T cells and CD14⁺ monocytes secreting TNF-α (p=0.013; p=0.001; p<0.001) were significantly decreased, and the percentage of CD8⁺ T cells secreting IL-17A (p=0.015) was significantly increased among the HT group. Both the percentages of CD4⁺ T cells secreting TGF-β (p<0.001; p=0.001), and CD4⁺ and CD8⁺ T cells secreting granzyme A (all p<0.001), were significantly higher among the HT group than among the TB group and HIV group. After one week's anti-TB treatment, an increased percentage of CD4⁺ T cells secreting TNF-α (p=0.003) was found in the TB group, and an increased percentage of CD8⁺ T cells secreting TNF-α (p=0.029) was found in the HT group.

Conclusion

Significantly different functional profiles of peripheral proinflammatory, regulatory, and cytotoxic cytokine-secreting cells were observed in the natural course of HIV/TB co-infection compared to TB and HIV infection alone, even though the absolute numbers of those cells were significantly lower in HIV/TB co-infection. TNF-α-secreting CD8⁺ T cells may be a more sensitive marker for early evaluation of anti-TB treatment efficacy in patients with HIV/TB co-infection.

Dominant expansion of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines in culture-positive lymph node tuberculosis

Lymph node culture-positive tuberculosis (LNTB+) is associated with increased mycobacterial antigen-induced pro-inflammatory cytokine production compared to LN culture-negative tuberculosis (LNTB-). However, the frequencies of CD4+, CD8+ T cells and NK cells expressing Th1/Tc1/Type 1 (IFNγ, TNFα, IL-2), Th17/Tc17/Type 17 (IL-17A, IL-17F, IL-22) cytokines and cytotoxic (perforin [PFN], granzyme [GZE] B, CD107a) markers in LNTB+ and LNTB- individuals are not known. Thus, we have studied the unstimulated (UNS) and mycobacterial antigen-induced frequencies of CD4+, CD8+ T and NK cells expressing Th1, Th17 cytokines and cytotoxic markers using flow cytometry. The frequencies of CD4+, CD8+ T and NK cells expressing cytokines and cytotoxic markers were not significantly different between LNTB+ and LNTB- individuals in UNS condition. In contrast, upon Mtb antigen stimulation, LNTB+ individuals are associated with significantly increased frequencies of CD4+ T cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [IFNγ, TNFα, IL-2]), CD8+ T cells (PPD [IFNγ], ESAT-6 PP [IFNγ], CFP-10 PP [TNFα]) and NK cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [TNFα]) expressing Th1/Tc1/Type 1, but not Th17/Tc17/Type 17 cytokines and cytotoxic markers compared to LNTB- individuals. LNTB+ individuals did not show any significant alterations in the frequencies of CD4+, CD8+ T cells and NK cells expressing cytokines and cytotoxic markers compared to LNTB- individuals upon HIV Gag PP and P/I antigen stimulation. Increased frequencies of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines among the LNTB+ group indicates that the presence of mycobacteria plays a dominant role in the activation of key correlates of immune protection or induces higher immunopathology.

Ex-vivo immunophenotyping and high dimensionality UMAP analysis of leucocyte subsets in tuberculous lymphadenitis

Tuberculous lymphadenitis (TBL) is defined by reduced proinflammatory cytokines and elevated CD4⁺, CD8⁺ T cells and decreased CD8⁺ cytotoxic markers. However, ex-vivo phenotyping of diverse leucocytes in TBL has not been done. We show activated and atypical B cells, myeloid dendritic cells (mDCs), classical, non-classical and intermediate monocytes, T regulatory (T regs) cells, CD4⁺ T cell effector memory RA (TEMRA), CD4⁺ effector and CD8⁺ central memory phenotypes were significantly increased in TBL compared to LTB individuals. In contrast, classical memory and plasma B cells, plasmacytoid DCs (pDCs), CD8⁺ TEMRA, CD4⁺ naïve and central memory cells were significantly decreased in TBL compared to LTB individuals. Some of the leucocyte frequencies (atypical memory B cells, pDCs, myeloid-derived suppressor cells, CD4⁺ effector and CD8⁺ central memory was increased; activated memory and plasma B cell, mDCs, classical, non-classical, intermediate monocytes, T regs, CD4⁺ TEMRA, CD4⁺, CD8⁺ naïve and effector memory cells and CD8⁺ central memory cells were decreased) were significantly modulated after anti-TB treatment among TBL individuals. UMAP analysis show that leucocyte subsets or islands expressing specific markers were significantly different in TBL baseline and post-treatment individuals. Overall, we suggest altered frequencies of diverse leucocytes influences the disease pathology and protective immunity in TBL individuals.

Diminished Frequencies of Cytotoxic Marker Expressing T- and NK Cells at the Site of Mycobacterium tuberculosis Infection

Tuberculous lymphadenitis (TBL) individuals exhibit reduced frequencies of CD8⁺ T cells expressing cytotoxic markers in peripheral blood. However, the frequencies of cytotoxic marker expressing CD4⁺, CD8⁺ T cells, and NK cells at the site of infection is not known. Therefore, we measured the baseline and mycobacterial antigen specific frequencies of cytotoxic markers expressing CD4⁺, CD8⁺ T cells, and NK cells in the LN (n = 18) and whole blood (n = 10) of TBL individuals. TBL LN is associated with lower frequencies of CD4⁺ T cells expressing cytotoxic markers (Granzyme B, CD107a) compared to peripheral blood at baseline and in response to PPD, ESAT-6, and CFP-10 antigen stimulation. Similarly, lower frequencies of CD8⁺ T cells expressing cytotoxic markers (Perforin, Granzyme B, and CD107a) were also present in the TBL LN at baseline and following (except perforin) antigen stimulation. Finally, at baseline and after antigen (PPD, ESAT-6, and CFP-10) stimulation, frequencies of NK cells expressing cytotoxic markers were also significantly lower in TBL LN compared to whole blood. Hence, TBL is characterized by diminished frequencies of cytotoxic marker expressing CD4⁺, CD8⁺ T cells, and NK cells at the site of infection, which might reflect the lack of protective immune responses at the site of Mycobacterium tuberculosis infection.

Enhanced Mycobacterial Antigen-Induced Pro-Inflammatory Cytokine Production in Lymph Node Tuberculosis

Lymph node tuberculosis (LNTB) is characterized by the enhanced baseline and antigen-specific production of type 1/17 cytokines and reduced baseline and antigen-specific production of interleukin (IL)-1β and IL-18 at the site of infection when compared with peripheral blood. However, the cytokine profile in the lymph nodes (LNs) of Mycobacterium tuberculosis culture-positive LNTB (LNTB+) and negative LNTB (LNTB-) has not been examined. To address this, we have examined the baseline and mycobacterial antigen-stimulated cytokine levels of type 1 (interferon gamma [IFNγ], tumor necrosis factor alpha [TNFα], IL-2), type 2 (IL-4, IL-5, and IL-13), type 17 (IL-17A, IL-17F, and IL-22), pro-inflammatory (IL-1α, IL-1β, IL-18, and granulocyte macrophage colony-stimulating factor [GM-CSF]), and regulatory cytokines (IL-10, transforming growth factor beta [TGF-β]) cytokines in the LN culture supernatants of LNTB+ and LNTB- individuals. We have observed significantly enhanced baseline levels of IL-13 and IL-10 and significantly reduced baseline levels of IL-4 and GM-CSF in LNTB+ individuals compared with LNTB- individuals. By contrast, we have observed significantly enhanced levels of type 1 (IFNγ, TNFα, and IL-2), type 17 (IL-17F and IL-22), and pro-inflammatory (IL-1α and GM-CSF) cytokines and significantly reduced levels of TGFβ in response to purified protein derivative, early secreted antigen-6, and culture filtrate protein-10 antigens in LNTB+ compared with LNTB- individuals. On phorbol 12-myristate 13-acetate/ionomycin stimulation, no significant difference was observed for any of the cytokines examined. Thus, our study revealed several interesting differences in the cytokine profiles of mycobacterial antigen-stimulated LN cultures in LNTB+ and LNTB- individuals. Therefore, we suggest the presence of mycobacteria plays a significant role in driving the cytokine response at the site of infection in LNTB.

Diminished type 1 and type 17 cytokine expressing - Natural killer cell frequencies in tuberculous lymphadenitis

Tuberculous lymphadenitis (TBL) is associated with the expansion of CD4⁺ and CD8⁺ T cells expressing Type 1 and Type 17 cytokines in the peripheral blood. However, the expression pattern of cytokine producing natural killer (NK) cells in both the peripheral blood and affected lymph nodes i.e. site of infection in TBL have not been examined. Hence, we have analyzed the baseline and mycobacterial antigen specific NK cell cytokine frequencies in whole blood of TBL and pulmonary tuberculosis (PTB) individuals. We have also examined the NK cell frequencies before and after treatment completion and in peripheral blood versus affected lymph nodes (LN) of TBL individuals. TBL is characterized by diminished frequencies of NK cells expressing Type 1 (IFNγ, TNFα), Type 17 (IL-17F) cytokines compared to PTB individuals upon antigen-specific stimulation. In contrast, TBL individuals did not exhibit any significant differences in the frequencies of NK cells expressing Type 1 and Type 17 cytokines upon completion of anti-tuberculosis treatment. LN of TBL is associated with altered frequencies of NK cells expressing Type 17 (increased IL-17F and decreased IL-22) cytokines when compared to peripheral blood. Thus, we conclude that TBL individuals are characterized by diminished frequencies of NK cells expressing Type 1/Type 17 cytokines.

Tuberculous Lymphadenitis Is Associated with Enhanced Baseline and Antigen-Specific Induction of Type 1 and Type 17 Cytokines and Reduced Interleukin-1β (IL-1β) and IL-18 at the Site of Infection

Tuberculous lymphadenitis (TBL) is characterized by an expansion of Th1 and Th17 cells with altered serum levels of proinflammatory cytokines. However, the cytokine profile at the site of infection, i.e., the affected lymph nodes, has not been examined in detail. To estimate the baseline and mycobacterial antigen-stimulated concentrations of type 1, type 17, and other proinflammatory cytokines in patients with TBL (n = 14), we examined both the baseline and the antigen-specific concentrations of these cytokines before and after chemotherapy and compared them with those in individuals with pulmonary tuberculosis (PTB) (n = 14). In addition, we also compared the cytokine responses in whole blood and those in the lymph nodes of TBL individuals. We observed significantly enhanced baseline and antigen-specific levels of type 1 cytokines (gamma interferon [IFN-γ] and tumor necrosis factor alpha [TNF-α]) and a type 17 cytokine (interleukin-17 [IL-17]) and significantly diminished baseline and antigen-specific levels of proinflammatory cytokines (IL-1β and IL-18) in the whole blood of TBL individuals compared to those in the whole blood of PTB individuals. Moreover, we also observed a pattern of baseline and antigen-specific cytokine production at the site of infection (lymph node) similar to that in the whole blood of TBL individuals. Following standard antituberculosis (anti-TB) treatment, we observed alterations in the baseline and/or antigen-specific levels of IFN-γ, TNF-α, IL-1β, and IL-18. TBL is therefore characterized by enhanced baseline and antigen-specific production of type 1 and type 17 cytokines and reduced baseline and antigen-specific production of IL-1β and IL-18 at the site of infection.

Reduced systemic and mycobacterial antigen-stimulated concentrations of IL-1β and IL-18 in tuberculous lymphadenitis

BACKGROUND

Type 1, Type 17 and other pro-inflammatory cytokines are known to play an important role in resistance to pulmonary tuberculosis. The role of these cytokines in tuberculous lymphadenitis (TBL) is not well characterized.

METHODS

To estimate the systemic and mycobacterial antigen - stimulated cytokine concentrations of Type 1, Type 17, other pro-inflammatory and regulatory cytokines in TBL, we examined both the systemic and the antigen-specific concentrations of these cytokines in TBL (n=31) before and after chemotherapy, and compared them with those with latent tuberculosis infection (LTB, n=31).

RESULTS

We observed significantly reduced systemic concentrations of the pro-inflammatory cytokines - IL-1β and IL-18 but not other Type 1 or Type 17 cytokines in TBL compared to LTB. Following standard anti-tuberculosis (TB) treatment, we observed a significant increase in the concentrations of both IL-1β and IL-18. In addition, we also observed significantly reduced baseline or mycobacterial - antigen or mitogen stimulated concentrations of IL-1β and IL-18 in TBL individuals. Similar to systemic cytokine concentrations, anti-TB treatment resulted in significantly increased concentrations of these cytokines following antigen stimulation.

CONCLUSIONS

TBL is therefore, characterized by reduced systemic and antigen-specific concentrations of IL-1β and IL-18, which are reversible following anti-TB treatment, indicating that these cytokines are potential correlates of protective immunity in TBL.

Phenotypic and functional characteristics of IL-21-expressing CD8(+) T cells in human nasal polyps

Although CD4⁺ T cells are recognized to play an important role in the inflammatory response of nasal polyps (NPs), the biological functions of CD8⁺ T cells in polypogenesis remain unclear. In this study, we analyzed cell markers, cytokine expression and transcription factors in IL-21-expressing CD8⁺ T cells in polyp tissues of NP patients. The results showed that the majority of IL-21-producing CD8⁺ T cells were effector memory cells and they co-expressed IFN-γ. IL-21-expressing CD8⁺ T cells in polyp tissues expressed higher CXCR5, PD-1, and ICOS levels than cells in control tissues and showed significantly higher T-bet and Bcl-6 expression levels compared with IL-21⁻CD8⁺ T cells. Purified polyp CD8⁺ T cells promoted IgG production from isolated polyp B cells in vitro, and recombinant IL-12 modulated the expression of IL-21, IFN-γ and CD40L in purified polyp CD8⁺ T cells. Moreover, the percentage of IL-21⁺CD8⁺ T cells in polyp tissues was positively correlated with endoscopic and CT scan scores in NP patients. These findings indicated that polyp CD8⁺ T cells, by co-expressing IL-21 and IFN-γ and other markers, display a Tfh cell functionality, which is associated with the clinical severity of NP patients.