Characterization of the immune impairment of patients with tuberculosis and COVID-19 coinfection.

OBJECTIVES: To characterize the plasma immune profile of patients with tuberculosis (TB)-COVID-19 compared with COVID-19, TB, or healthy controls and to evaluate in vitro the specific responses to SARS-CoV-2 and Mycobacterium tuberculosis (Mtb)-antigens. METHODS: We enrolled 119 subjects: 14 TB-COVID-19, 47 COVID-19, 38 TB, and 20 controls. The plasmatic levels of 27 immune factors were measured at baseline using a multiplex assay. The specific response to SARS-CoV-2 and Mtb antigens was evaluated using a home-made whole blood platform and QuantiFERON-Plus tubes, respectively. RESULTS: We found an immune signature (tumor necrosis factor [TNF]-α, macrophage inflammatory protein-1ß, and interleukin [IL]-9) associated with TB-COVID-19 coinfection compared with COVID-19 (P <0.05), and TNF-α showed the highest discriminant power. We also found another signature (TNF-α, IL-1ß, IL-17A, IL-5, fibroblast growth factor-basic, and granulocyte macrophage colony-stimulating factor [GM-CSF]) in coinfected patients compared with patients with TB (P <0.05), and among them, TNF-α and granulocyte macrophage colony-stimulating factor showed a non-negligible discriminating ability. Moreover, coinfected patients showed a significantly reduced SARS-CoV-2-specific response compared with COVID-19 for several pro-inflammatory cytokines/chemokines, anti-inflammatory cytokines, and growth factors (P ≤0.05). Furthermore, coinfection negatively affected the Mtb-specific response (P ≤0.05). CONCLUSION: We found immune signatures associated with TB-COVID-19 coinfection and observed a major impairment of SARS-CoV-2-specific and, to a lesser extent, the Mtb-specific immune responses. These findings further advance our knowledge of the immunopathology of TB-COVID-19 coinfection.

Evaluation of the immunomodulatory effects of interleukin-10 on peripheral blood immune cells of COVID-19 patients: Implication for COVID-19 therapy.

Objective: Several therapies with immune-modulatory functions have been proposed to reduce the overwhelmed inflammation associated with COVID-19. Here we investigated the impact of IL-10 in COVID-19, through the ex-vivo assessment of the effects of exogenous IL-10 on SARS-CoV-2-specific-response using a whole-blood platform. Methods: Two cohorts were evaluated: in "study population A", plasma levels of 27 immune factors were measured by a multiplex (Luminex) assay in 39 hospitalized "COVID-19 patients" and 29 "NO COVID-19 controls" all unvaccinated. In "study population B", 29 COVID-19 patients and 30 NO COVID-19-Vaccinated Controls (NO COVID-19-VCs) were prospectively enrolled for the IL-10 study. Whole-blood was stimulated overnight with SARS-COV-2 antigens and then treated with IL-10. Plasma was collected and used for ELISA and multiplex assay. In parallel, whole-blood was stimulated and used for flow cytometry analysis. Results: Baseline levels of several immune factors, including IL-10, were significantly elevated in COVID-19 patients compared with NO COVID-19 subjects in "study population A". Among them, IL-2, FGF, IFN-γ, and MCP-1 reached their highest levels within the second week of infection and then decreased. To note that, MCP-1 levels remained significantly elevated compared with controls. IL-10, GM-CSF, and IL-6 increased later and showed an increasing trend over time. Moreover, exogenous addition of IL-10 significantly downregulated IFN-γ response and several other immune factors in both COVID-19 patients and NO COVID-19-VCs evaluated by ELISA and a multiplex analysis (Luminex) in "study population B". Importantly, IL-10 did not affect cell survival, but decreased the frequencies of T-cells producing IFN-γ, TNF-α, and IL-2 (p<0.05) and down-modulated HLA-DR expression on CD8+ and NK cells. Conclusion: This study provides important insights into immune modulating effects of IL-10 in COVID-19 and may provide valuable information regarding the further in vivo investigations.

Kinetics of the B- and T-Cell Immune Responses After 6 Months From SARS-CoV-2 mRNA Vaccination in Patients With Rheumatoid Arthritis.

Objective: To assess the kinetics of the humoral and cell-mediated responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in rheumatoid arthritis (RA) patients treated with different immunosuppressive therapies. Methods: Following vaccine completed schedule, health care workers (HCWs, n = 49) and RA patients (n = 35) were enrolled at 5 weeks (T1) and 6 months (T6) after the first dose of BNT162b2-mRNA vaccination. Serological response was assessed by quantifying anti-receptor-binding domain (RBD)-specific immunoglobulin G (IgG) and SARS-CoV-2 neutralizing antibodies, while cell-mediated response was assessed by a whole-blood test quantifying the interferon (IFN)-γ response to spike peptides. B-cell phenotype and IFN-γ-specific T-cell responses were evaluated by flow cytometry. Results: After 6 months, anti-RBD antibodies were still detectable in 91.4% of RA patients, although we observed a significant reduction of the titer in patients under Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4)-Ig [median: 16.4 binding antibody units (BAU)/ml, interquartile range (IQR): 11.3-44.3, p < 0.0001] or tumor necrosis factor (TNF)-α inhibitors (median: 26.5 BAU/ml, IQR: 14.9-108.8, p = 0.0034) compared to controls (median: 152.7 BAU/ml, IQR: 89.3-260.3). All peripheral memory B-cell (MBC) subpopulations, in particular, the switched IgG+ MBCs (CD19+CD27+IgD-IgM-IgG+), were significantly reduced in RA subjects under CTLA-4-Ig compared to those in HCWs (p = 0.0012). In RA patients, a significantly reduced anti-RBD IgG titer was observed at T6 vs. T1, mainly in those treated with CTLA-4-Ig (p = 0.002), interleukin (IL)-6 inhibitors (p = 0.015), and disease-modifying antirheumatic drugs (DMARDs) ± corticosteroids (CCSs) (p = 0.015). In contrast, a weak nonsignificant reduction of the T-cell response was reported at T6 vs. T1. T-cell response was found in 65.7% of the RA patients at T6, with lower significant magnitude in patients under CTLA-4-Ig compared to HCWs (p < 0.0001). The SARS-CoV-2 IFN-γ-S-specific T-cell response was mainly detected in the CD4+ T-cell compartment. Conclusions: In this study, in RA patients after 6 months from COVID-19 vaccination, we show the kinetics, waning, and impairment of the humoral and, to a less extent, of the T-cell response. Similarly, a reduction of the specific response was also observed in the controls. Therefore, based on these results, a booster dose of the vaccine is crucial to increase the specific immune response regardless of the immunosuppressive therapy.

Mycobacterium tuberculosis Immune Response in Patients With Immune-Mediated Inflammatory Disease.

Subjects with immune-mediated inflammatory diseases (IMID), such as rheumatoid arthritis (RA), have an intrinsic higher probability to develop active-tuberculosis (TB) compared to the general population. The risk ranges from 2.0 to 8.9 in RA patients not receiving therapies. According to the WHO, the RA prevalence varies between 0.3% and 1% and is more common in women and in developed countries. Therefore, the identification and treatment of TB infection (TBI) in this fragile population is important to propose the TB preventive therapy. We aimed to study the M. tuberculosis (Mtb) specific T-cell response to find immune biomarkers of Mtb burden or Mtb clearance in patients with different TB status and different risk to develop active-TB disease. We enrolled TBI subjects as example of Mtb-containment, the active-TB as example of a replicating Mtb status, and the TBI-IMID as fragile population. To study the Mtb-specific response in a condition of possible Mtb sterilization, we longitudinally enrolled TBI subjects and active-TB patients before and after TB therapy. Peripheral blood mononuclear cells were stimulated overnight with Mtb peptides contained in TB1- and TB2-tubes of the Quantiferon-Plus kit. Then, we characterized by cytometry the Mtb-specific CD4 and CD8 T cells. In TBI-IMID, the TB therapy did not affect the ability of CD4 T cells to produce interferon-γ, tumor necrosis factor-α, and interleukin-2, their functional status, and their phenotype. The TB therapy determined a contraction of the triple functional CD4 T cells of the TBI subjects and active-TB patients. The CD45RA- CD27+ T cells stood out as a main subset of the Mtb-specific response in all groups. Before the TB-preventive therapy, the TBI subjects had higher proportion of Mtb-specific CD45RA-CD27+CD4+ T cells and the active-TB subjects had higher proportion of Mtb-specific CD45RA-CD27-CD4+ T cells compared to other groups. The TBI-IMID patients showed a phenotype similar to TBI, suggesting that the type of IMID and the IMID therapy did not affect the activation status of Mtb-specific CD4 T cells. Future studies on a larger and better-stratified TBI-IMID population will help to understand the change of the Mtb-specific immune response over time and to identify possible immune biomarkers of Mtb-containment or active replication.

A whole blood test to measure SARS-CoV-2-specific response in COVID-19 patients.

OBJECTIVES: To examine whether specific T-cell-responses to SARS-CoV-2 peptides can be detected in COVID-19 using a whole-blood experimental setting, which may be further explored as a potential diagnostic tool. METHODS: We evaluated interferon (IFN)-γ levels after stimulating whole-blood with spike and remainder-antigens peptides megapools (MP) derived from SARS-CoV-2 sequences; interleukin (IL)-1ß, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-15, IL-17A, eotaxin, basic fibroblast growth factor (FGF), granulocyte-colony stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IFN-γ, Interferon gamma-induced protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α, MIP-1ß, Platelet-derived growth factor (PDGF), RANTES (regulated on activation, normal T cell expressed and secreted), tumour necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF) were also evaluated. RESULTS: IFN-γ-response to spike and remainder-antigens MPs was significantly increased in 35 COVID-19 patients compared with 29 'no COVID-19' individuals (medians spike-MP: 0.26 vs 0, p = 0.0002; medians remainder-antigens-MP: 0.07 vs 0.02; p = 0.02). This response was detected independently of patients' clinical parameters. IFN-γ-response to SARS-CoV-2-unrelated antigens cytomegalovirus (CMV) and Staphylococcal Enterotoxin B (SEB) was similar in COVID-19 compared with 'no COVID-19' individuals (median CMV: 3.46 vs 5.28, p = 0.16; median SEB: 12.68 vs 15.05; p = 0.1). In response to spike-MPs in COVID-19- compared with 'no COVID-19' -individuals, we found significant higher median of IL-2 (50.08 vs 0, p = 0.0018), IFN-γ (90.16 vs 0, p = 0.01), IL-4 (0.52 vs 0, p = 0.03), IL-13 (0.84 vs 0, p = 0.007) and MCP-1 (4602 vs 359.2, p = 0.05). CONCLUSIONS: Immune response to SARS-CoV-2 peptides in a whole-blood assay is associated with COVID-19 and it is characterized by both Th1 and Th2 profile. This experimental approach may be useful for developing new T-cell based diagnostic tests for disease and vaccine settings.

Optimization of the autophagy measurement in a human cell line and primary cells by flow cytometry.

The limited availability of rapid and reliable flow cytometry-based assays for ex vivo quantification of autophagy has hampered their clinical applications for studies of diseases pathogenesis or for the implementation of autophagy-targeting therapies. To this aim, we modified and improved the protocol of a commercial kit developed for quantifying the microtubule-associated protein 1A/1B light chain 3B (LC3), the most reliable marker for autophagosomes currently available. The protocol modifications were set up measuring the autophagic flux in neoplastic (THP-1 cells) and primary cells (peripheral blood mononuclear cells; PBMC) of healthy donors. Moreover, PBMC of active tuberculosis (TB) patients were stimulated with the Mycobacterium tuberculosis purified protein derivatives or infected with live Mycobacterium bovis bacillus Calmette-Guerin (BCG). We found that the baseline median fluorescent intensity (MFI) of THP-1 cells changed depending on the time of sample acquisition to the flow cytometer. To solve this problem, a fixation step was introduced in different stages of the assay's protocol, obtaining more reproducible and sensitive results when a post-LC3 staining fixation was performed, in either THP1 or PBMC. Furthermore, since we found that results are influenced by the type and the dose of the lysosome inhibitor used, the best dose of Chloroquine for LC3 accumulation were set up in either THP-1 cells or PBMC. Finally, applying these experimental settings, we measured the autophagic flux in CD14+ cells from active TB patients' PBMC upon BCG infection. In conclusion, our data indicate that the protocol modifications here described in this work improve the stability and accuracy of a flow cytometry-based assay for the evaluation of autophagy, thus assuring more standardised cell analyses.

Characterization of QuantiFERON-TB-Plus results in latent tuberculosis infected patients with or without immune-mediated inflammatory diseases.

OBJECTIVES: Screening for latent tuberculosis infection (LTBI) diagnosis is mandatory in patients with immune-mediated inflammatory diseases (IMID) requiring biologics. QuantiFERON-TB-Plus (QFT-P), an LTBI diagnostic test, measures IFN-γ after M. tuberculosis-stimulation in TB1 and TB2 tubes in which a "CD4" or a "CD4 and CD8" response is respectively elicited. Aim of this study is to compare the response to QFT-P of IMID-LTBI patients candidates to a new biological therapy vs LTBI-subjects without IMID. METHODS: We prospectively enrolled 167 subjects: 61 IMID-LTBI and 106 NON-IMID-LTBI. RESULTS: All subjects were mitogen-responders. IFN-γ production was significantly lower in IMID-LTBI-patients compared to NON-IMID-LTBI-subjects. We observed discordant TB1 and TB2 results in 6.5% of IMID-LTBI-patients and in 8% of NON-IMID-LTBI-subjects. Applying a logistic regression analysis, we found that IMID-LTBI patients had a higher probability (TB1 stimulation OR 3.32; TB2 stimulation OR 4.33) to have IFNγ results ≤0.7 IU/mL compared to NON-IMID-LTBI-subjects. Interestingly, IMID-treatment did not interfere with the distribution of IFNγ-values. CONCLUSIONS: These results indicate that IMID-LTBI-patients have a low IFN-γ response to QFT-P, a high proportion of results ranging in the grey zone and a distribution of IFNγ-values independent from the IMID-treatment. These results are important for the management of LTBI screening in IMID patients.

Interplay of DDP4 and IP-10 as a Potential Mechanism for Cell Recruitment to Tuberculosis Lesions.

INTRODUCTION: Mycobacterium tuberculosis is one of the world's most successful pathogens equipped to establish itself within the human host as a subclinical infection without overt disease. Unable to eradicate the bacteria, the immune system contains the infection in a granuloma structure. Th1 cells that are essential for infection control are recruited to the site of infection directed by chemokines, predominantly CXCL10. It has previously been shown that CXCL10 in the plasma of patients chronically infected with hepatitis C virus is present primarily in an antagonist form. This is due to N-terminal truncation by the enzyme DPP4, which results in the antagonist form that is capable of binding its receptor CXCR3, but does not induce signaling. We aimed to explore whether such CXCL10 antagonism may have an impact on the pathogenesis of tuberculosis (TB). RESULTS: We measured plasma levels of agonist and antagonist CXCL10 by Simoa digital ELISA, as well as DPP4 enzyme activity in the plasma of 20 patients with active TB infection, 10 patients with pneumonia infection, and a group of 10 healthy controls. We found higher levels of total and antagonist CXCL10 and reduced DPP4 enzyme activity in the plasma of TB patients compared to controls. We traced the source of CXCL10 secretion using immunohistochemical and confocal analysis to multinucleated giant cells in the TB lesions, and variable expression by macrophages. Interestingly, these cells were associated with DPP4-positive T cells. Moreover, the analysis of lymphocytes at the site of TB infection (bronchoalveolar lavage) showed a reduced frequency of CXCR3+ T cells. INTERPRETATION: Our data suggests that CXCL10 antagonism may be an important regulatory mechanism occurring at the site of TB pathology. CXCL10 can be inactivated shortly after secretion by membrane bound DPP4 (CD26), therefore, reducing its chemotactic potential. Given the importance of Th1 cell functions and IFN-γ-mediated effects in TB, our data suggest a possible unappreciated regulatory role of DPP4 in TB. PERSPECTIVES: DPP4 is the target for a class of enzyme inhibitors used in the treatment of diabetes, and the results from this study suggest that these drugs could be repurposed as an adjunct immunotherapy of patients with TB and MDR-TB.

Immune characterization of the HBHA-specific response in Mycobacterium tuberculosis-infected patients with or without HIV infection.

INTRODUCTION: RD1-based Interferon-γ Release Assays (IGRAs) cannot distinguish latent from active tuberculosis (TB) disease. Conversely, a positive response to heparin-binding haemagglutinin (HBHA)-based IGRAs, among TB-infected subjects, correlates with Mycobacterium tuberculosis (Mtb) containment and low risk of TB progression. The aim of this study was to characterize HBHA-immune responses in HIV-infected and uninfected subjects with active TB or latent TB infection (LTBI). METHODS: 49 subjects were prospectively enrolled: 22 HIV-uninfected (13 TB, 9 LTBI) and 27 HIV-infected (12 HIV-TB, 15 HIV-LTBI). Whole blood and peripheral blood mononuclear cells were stimulated with HBHA and RD1 antigens. Interferon (IFN)γ release was evaluated by ELISA whereas cytokine profile [IFNγ, tumor necrosis (TNF)α, interleukin (IL)2] and phenotype (CD45RA, CCR7) by flow cytometry. RESULTS: Among LTBI individuals, HBHA stimulation induced IFNγ release in all the HIV-uninfected, while, only 4/15 HIV-infected responded. Within the active TB, only 5/13 HIV-uninfected and 1/12 HIV-TB patients responded. Interestingly, by cytometry we showed that CD4+ T-cells response to HBHA was significantly impaired in the HIV-infected subjects with TB or LTBI compared to the HIV-uninfected subjects. The phenotype of HBHA-specific CD4 T-cells showed a predominantly central memory (CM) and effector memory (EM) phenotype without differences among the groups. Differently, HBHA-specific CD8+ T-cells, showed mainly a CM and naïve phenotype in LTBI group while TB, HIV-LTBI and HIV-TB groups were characterized by EM or terminally differentiated phenotypes. Interestingly, differently than what observed for RD1, the cytokine profile of HBHA-specific T-cells evaluated by cytometry showed that the CD4+ T-cells were mostly monofunctional. Conversely, CD8-specific T-cells were mostly monofunctional for both HBHA and RD1 stimulations. CONCLUSIONS: These results characterize the impact of HIV infection in CD4- and CD8-specific response to HBHA in both LTBI and TB patients. HIV infection impairs the CD4 response to HBHA and likely this may lead to an impairment of TB control.

Use of several immunological markers to model the probability of active tuberculosis.

Blood-based biomarkers tests are attractive alternative for diagnosing tuberculosis to assays depending on mycobacteria detection. Given several immunological markers we used logistic regression to model the probability of active tuberculosis in a cohort of patients with active or latent tuberculosis, showing an increased accuracy in distinguishing active from latent tuberculosis.

KLRG1 and PD-1 expression are increased on T-cells following tuberculosis-treatment and identify cells with different proliferative capacities in BCG-vaccinated adults.

In cancer and chronic infectious diseases, immune checkpoint-blockade of inhibitory receptors can enhance T-cell immunity. In tuberculosis (TB), a chronic infectious disease, prolonged antigen exposure can potentially drive terminal T-cell differentiation towards functional 'exhaustion': in human TB T-cells express PD-1 (programmed cell death protein-1) and CTLA-4 (cytotoxic T-lymphocyte-associated protein-4). However, in murine TB not PD-1 but rather killer cell lectin-like receptor subfamily-G1 (KLRG1) was a superior indicator of terminal T-cell differentiation. We therefore compared expression of KLRG1, PD-1 and CTLA-4 on T-cells in different stages of human TB, and also analysed their induction following BCG-vaccination. KLRG1, PD-1 and CTLA-4-expression were highest on in vitro BCG-stimulated CD4(+) T-cells following recent TB-treatment; KLRG1 and PD-1-expression on CD4(+) T-cells in active--but not latent--TB were only slightly increased compared to healthy donors. BCG-vaccination induced KLRG1-expression on BCG-stimulated CD8(+) but not CD4(+) T-cells, while neither PD-1 nor CTLA-4-expression increased. KLRG1-expressing CD8(+) T-cells exhibited markedly decreased proliferation, whereas PD-1(+) T-cells proliferated after in vitro BCG-stimulation. Thus, we demonstrate the presence of increased KLRG1-expressing T-cells in TB-treated individuals, and present KLRG1 as a marker of decreased human T-cell proliferation following BCG-vaccination. These results expand our understanding of cell-mediated immune control of mycobacterial infections.

Modulation of CD4 and CD8 response to QuantiFERON-TB Plus in patients with active tuberculosis and latent tuberculosis infection followed over time during treatment.

OBJECTIVE/BACKGROUND: Interferon (IFN)-γ release assays (IGRA) are designed for diagnosing tuberculosis (TB) infection. The new IGRA, QuantiFERON-TB Plus (QFT-Plus), is based on the enzyme-linked immunosorbent assay detection of IFN-γ after stimulation with Mycobacterium tuberculosis TB1 and TB2 antigens. TB1 elicits a cellular-mediated immune (CMI) response by CD4 T cells, and TB2 contains peptides recognized by both CD4 and CD8 T cells. The aim of the study is to characterize the CMI to QFT-Plus peptides in active TB and latent TB infection (LTBI) at baseline and during or after specific treatment (follow-up). METHODS: We enrolled 7 individuals with active TB and 11 individuals with LTBI at baseline and followed them during the treatment, either for active diseases or preventive therapy. Peripheral blood mononuclear cells were stimulated with QFT-Plus antigens (TB1, TB2, and mitogen). Cytokine profile (IFN-γ, tumor necrosis factor-α, interleukin-2) and phenotype (CD45RA, CD27) of CD4 and CD8 T cells were characterized by flow cytometry. RESULTS: All the individuals responded to mitogen. CD4 T-cell responses to TB1 and TB2 were similar in both individuals with active TB and those with LTBI evaluated over time. Differently, we found a higher number of TB2-associated CD8 T-cell responders in individuals with active TB than in those with LTBI. For individuals with active TB, there was no change in the specific response overtime. Differently, in individuals with LTBI, the number of CD8 responders to QFT-Plus antigens increased during preventive treatment (TB1=5/11 [45%], TB2=5/11 [45%]) compared with that at the time of enrolment (TB1=1/11 [9%], TB2=1/11 [9%]). Moreover, we analyzed the effector memory profile of T cells responding to QFT-Plus antigens. The largest component of antigen-specific CD4 T cells (65%) had a central memory (CD45RA-CD27+) phenotype at enrolment and during follow-up. In contrast, specific CD8 T cells, which were analyzed only at follow-up because they were almost absent at baseline, were characterized by a large component with naïve (CD45RA+CD27+) phenotype (40%) and a minor component with central memory (25%) features. CONCLUSION: To our knowledge, this is the first report characterizing CD4 and CD8 T-cell responses of individuals with active TB and with LTBI, followed overtime, to QFT-Plus antigens by flow cytometry. The results, although preliminary, may help in identifying better tools for monitoring therapy, especially in those with LTBI undergoing preventive treatment.

Polyfunctional Specific Response to Echinococcus Granulosus Associates to the Biological Activity of the Cysts.

BACKGROUND: Cystic echinococcosis (CE) is a complex disease caused by Echinococcus granulosus (E.granulosus), and its immunophatogenesis is still not clearly defined. A peculiar feature of chronic CE is the coexistence of Th1 and Th2 responses. It has been suggested that Th1 cytokines are related to disease resistance, whereas Th2 cytokines are related to disease susceptibility and chronicity. The aim of this study was to evaluate, by multi-parametric flow cytometry (FACS), the presence of CE specific immune signatures. METHODOLOGY/PRINCIPAL FINDINGS: We enrolled 54 subjects with suspected CE; 42 of them had a confirmed diagnosis, whereas 12 were classified as NO-CE. Based on the ultrasonography images, CE patients were further categorized as being in "active stages" (25) and "inactive stages" (17). The ability of CD4+ T-cells to produce IFN-γ, IL-2, TNF-α, Th2 cytokines or IL-10 was assessed by FACS on antigen-specific T-cells after overnight stimulation with Antigen B (AgB) of E.granulosus. Cytokine profiles were evaluated in all the enrolled subjects. The results show that none of the NO-CE subjects had a detectable AgB-specific response. Among the CE patients, the frequency and proportions of AgB-specific CD4+ T-cells producing IL-2+TNF-α+Th2+ or TNF-α+Th2+ were significantly increased in the "active stages" group compared to the "inactive stages" group. Moreover, an increased proportion of the total polyfunctional subsets, as triple-and double-functional CD4 T-cells, was found in CE patients with active disease. The response to the mitogen, used as a control stimulus to evaluate the immune competence status, was characterized by the same cytokine subsets in all the subjects enrolled, independent of CE. CONCLUSIONS: We demonstrate, for the first time to our knowledge, that polyfunctional T-cell subsets as IL-2+TNF-α+Th2+ triple-positive and TNF-α+Th2+ double-positive specific T-cells associate with cyst biological activity. These results contribute to increase knowledge of CE immunophatogenesis and the disease outcome in terms of control and persistence.

Assessment of CD27 expression as a tool for active and latent tuberculosis diagnosis.

UNLABELLED: There are still no reliable tests to distinguish active tuberculosis (TB) from latent TB infection (LTBI). Assessment of CD27 modulation on CD4⁺ T-cells has been suggested as a tool to diagnose different TB stages. OBJECTIVES: To use several cytometric approaches to evaluate CD27 expression on Mycobacterium tuberculosis (Mtb)-specific CD4⁺ T-cells to differentiate TB stages. METHODS: 55 HIV-uninfected subjects were enrolled: 13 active TB; 12 cured TB; 30 LTBI. Whole blood was stimulated with RD1-proteins or Cytomegalovirus-lysate (CMV). Interferon (IFN)-γ response was evaluated by cytometry. The proportion of CD27(±) within the IFN-γ⁺ CD4⁺ T-cells or RATIO of the CD27-median fluorescence intensity (MFI) of CD4⁺ T-cells over the CD27 MFI of IFN-γ⁺ CD4⁺ T-cells was evaluated. RESULTS: The greatest diagnostic accuracy in discriminating active TB vs. LTBI or cured TB was reached by evaluating the CD27(+) CD45RA(-) cells within the IFN-γ⁺ CD4⁺ T-cell subset (76.92 sensitivity for both, and 90% and 91.67% specificity, respectively), although the use of the CD27 MFI RATIO allows for stricter data analysis, independent of the operator. CONCLUSIONS: the study of CD27 expression using different approaches, whether it involves evaluation of CD45RA expression or not, is a robust biomarker for discriminating TB stages.

IL-4 specific-response in whole blood associates with human Cystic Echinococcosis and cyst activity.

OBJECTIVES: Human Cystic Echinococcosis (CE) is estimated in 2-3 million global cases. CE diagnosis and clinical management are based on imaging and serology, which lacks sensitivity and does not provide cyst stage information. This study aimed to evaluate tools for improving diagnosis by analysing the Interleukin (IL)-4-response to Antigen B (AgB) of Echinococcus granulosus. METHODS: Whole blood (WB) and peripheral blood mononuclear cells were stimulated with AgB. IL-4 levels were measured by enzyme-linked immunosorbent assay. RESULTS: WB 1-day stimulation resulted the best experimental condition for evaluating AgB IL-4-response. IL-4 levels were significantly higher in CE patients than healthy donors (p ≤ 0.0001). A ROC analysis showed significant area under the curve (AUC) results (AUC, 0.85; p = 0.0001) identifying an IL-4 level cut-off point ≥0.39 pg/mL which predicted CE with 71.4% sensitivity and 93.3% specificity. Moreover, we found that IL-4 levels were significantly increased in patients with active cysts compared to those with inactive cysts (p ≤ 0.0001). ROC analysis showed significant AUC results (0.94; p = 0.0001) with a cut-off point of 4.6 pg/mL which predicted active cysts with 84.6% sensitivity and 92% specificity. CONCLUSIONS: We found immunological correlates associated with CE and biological cyst activity.

Polyfunctional T-cells and effector memory phenotype are associated with active TB in HIV-infected patients.

OBJECTIVES: Polyfunctional T-cells associate with chronic viral infection control while their involvement in tuberculosis (TB) is unclear. We evaluated TB-specific polyfunctional T-cell response and memory status in antiretroviral treatment (ART)-naïve HIV-infected patients from a low TB-endemic country. METHODS: We prospectively enrolled HIV-infected patients, 12 with active TB (HIV-TB) and 15 with latent tuberculosis infection (LTBI). Peripheral blood cells were stimulated with TB antigens (RD1 proteins/peptides), HIV antigens, cytomegalovirus (CMV) and staphylococcal enterotoxin B (SEB) and analyzed by cytometry. RESULTS: The HIV-TB showed a higher frequency of polyfunctional CD4(+) T-cells in response to RD1 antigens than HIV-LTBI (p = 0.007). Among the CD8(+) T-cells, both groups showed a significantly higher frequency of RD1-specific monofunctional cells than polyfunctional cells (p = 0.03). Analyzing the cytokine profile, IFNγ(+) TNFα(+) CD4(+) T-cells associated with HIV-TB (p ≤ 0.02) whereas IL2(+) TNFα(+) associated with HIV-LTBI (p = 0.009). CD4(+) T-cell response presented an effector-memory status in HIV-TB (p = 0.007) and an effector-memory terminally-differentiated phenotype in HIV-LTBI (p = 0.03). CD8(+) T-cell response presented an effector status in HIV-LTBI (p = 0.02). No significant cytokine profile pattern associated with responses to the other stimuli tested. CONCLUSIONS: In HIV-infection, polyfunctional CD4(+) T-cell-response associates with active TB, characterized by a high proportion of IFNγ(+) TNFα(+) and an effector-memory phenotype.

IFNγ/TNFα specific-cells and effector memory phenotype associate with active tuberculosis.

OBJECTIVES: Controversial results were reported on the role of polyfunctional T-cells in tuberculosis (TB). Our aim was to simultaneously characterize the Mycobacterium tuberculosis (Mtb)-specific immune response as cytokine production and memory phenotype by flow cytometry after in vitro stimulation with region of difference 1 ("RD1") recombinant proteins (ESAT-6 and CFP-10) in patients at different TB stage in a low TB endemic country. To assess the specificity of these findings, we evaluated the response to cytomegalovirus (CMV), an unrelated antigen. METHODS: We enrolled subjects with active TB, cured TB, latent TB infection (LTBI). Cytokine and phenotype profiles of T-cells from whole blood stimulated with "RD1" proteins and CMV were characterized by multi-parametric flow cytometry. RESULTS: Bifunctional IFNγ(+) TNFα(+) CD4(+) T-cells and effector memory phenotype significantly associated with active TB compared to the LTBI group (p = 0.008, at least p ≤ 0.009 respectively) whereas "RD1"-T-cell response in cured TB and LTBI was characterized by a central memory phenotype (at least p ≤ 0.013 and p ≤ 0.004 respectively vs active TB). In contrast, response to CMV antigen was not associated with a TB-specific status. CONCLUSION: We identified qualitative associations between Mtb-specific T-cell and TB status in terms of functional capacity and memory status. These immune correlates may be helpful to trace natural history of TB.