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Introduction: Tuberculosis (TB) remains a significant health concern in India, and its complexity is exacerbated by the rising occurrence of non-communicable diseases such as diabetes mellitus (DM). Recognizing that DM is a risk factor for active TB, the emerging comorbidity of TB and PDM (TB-PDM) presents a particular challenge. Our study focused on the impact of PDM on cytokine and chemokine profiles in patients with pulmonary tuberculosis TB) who also have PDM. Materials and methods: We measured and compared the cytokine (GM-CSF, IFN-γ, IL-1α/IL-1F1, IL-1β/IL-1F2, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-17/IL-17A, IL-18/IL-1F4, TNF-α) and chemokine (CCL1, CCL2, CCL3, CCL4, CCL11, CXCL1, CXCL2, CXCL9, CXCL10, and CXCL11) levels in plasma samples of TB-PDM, only TB or only PDM using multiplex assay. Results: We observed that PDM was linked to higher mycobacterial loads in TB. Patients with coexisting TB and PDM showed elevated levels of various cytokines (including IFNγ, TNFα, IL-2, IL-17, IL-1α, IL-1β, IL-6, IL-12, IL-18, and GM-CSF) and chemokines (such as CCL1, CCL2, CCL3, CCL4, CCL11, CXCL1, CXCL9, CXCL10, and CXCL11). Additionally, cytokines such as IL-18 and GM-CSF, along with the chemokine CCL11, were closely linked to levels of glycated hemoglobin (HbA1c), hinting at an interaction between glycemic control and immune response in TB patients with PDM. Conclusion: Our results highlight the complex interplay between metabolic disturbances, immune responses, and TB pathology in the context of PDM, particularly highlighting the impact of changes in HbA1c levels. This emphasizes the need for specialized approaches to manage and treat TB-PDM comorbidity. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial peptides are an important component of host defense against Mycobacterium tuberculosis. However, the ability of BCG to induce AMPs as part of its mechanism of action has not been investigated in detail. Methods: We investigated the impact of Bacillus Calmette–Guerin (BCG) vaccination on circulating plasma levels and TB-antigen stimulated plasma levels of AMPs in a healthy elderly population. We assessed the association of AMPs, including Human Beta Defensin 2 (HBD-2), Human Neutrophil Peptide 1-3 (HNP1-3), Granulysin, and Cathelicidin (LL37), in circulating plasma and TB-antigen stimulated plasma (using IGRA supernatants) at baseline (pre-vaccination) and at Month 1 and Month 6 post vaccination. Results: Post BCG vaccination, both circulating plasma levels and TB-antigen stimulated plasma levels of AMPs significantly increased at Month 1 and Month 6 compared to pre-vaccination levels in the elderly population. However, the association of AMP levels with latent TB (LTB) status did not exhibit statistical significance. Conclusion: Our findings indicate that BCG vaccination is linked to heightened circulating levels of AMPs in the elderly population, which are also TB-antigen-specific. This suggests a potential mechanism underlying the immune effects of BCG in enhancing host defense against TB. [ABSTRACT FROM AUTHOR]

Background: In the first year of roll-out, vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prevented almost 20 million deaths from coronavirus disease 2019 (COVID-19). Yet, little is known about the factors influencing access to vaccination at the individual level within rural poor settings of low-income countries. The aim of this study was to examine determinants of vaccine receipt in rural India. Methods: A census of a rural village in Tamil Nadu was undertaken from June 2021 to September 2022. We surveyed 775 participants from 262 households. Household-level data on socioeconomic status (SES), water, sanitation, and hygiene practices, and individual-level demographic information, travel history, and biomedical data, including anthropometry, vital signs, and comorbidities, were collected. Logistic regression models with 5-fold cross-validation were used to identify the biomedical, demographic, and socioeconomic determinants of vaccine receipt and the timing of receipt within the first 30 days of eligibility. Vaccine ineligible participants were excluded leaving 659 eligible participants. There were 650 eligible participants with complete biomedical, demographic, and socioeconomic data. Results: There were 68.0% and 34.0% of individuals (N = 650) who had received one and two vaccine doses, respectively. Participants with household ownership of a permanent account number (PAN) or ration card were 2.15 (95% CI:1.32–3.52) or 3.02 (95% CI:1.72–5.29) times more likely to receive at least one vaccine dose compared to households with no ownership of such cards. Participants employed as housewives or self-employed non-agricultural workers were 65% (95% CI:0.19–0.67) or 59% (95% CI:0.22–0.76) less likely to receive at least one vaccine dose compared to salaried workers. Household PAN card ownership, occupation and age were linked to the timing of vaccine receipt. Participants aged ≤18 and 45–60 years were 17.74 (95% CI:5.07–62.03) and 5.51 (95% CI:2.74–11.10) times more likely to receive a vaccine within 30 days of eligibility compared to 19-44-year-olds. Biomedical factors including BMI, vital signs, comorbidities, and COVID-19 specific symptoms were not consistently associated with vaccine receipt or timing of receipt. No support was found that travel history, contact with COVID-19 cases, and hospital admissions influenced vaccine receipt or timing of receipt. Conclusion: Factors linked to SES were linked to vaccine receipt, more so than biomedical factors which were targeted by vaccine policies. Future research should explore if government interventions including vaccine mandates, barriers to vaccine access, or peer influence linked to workplace or targeted vaccine promotion campaigns underpin these findings. [ABSTRACT FROM AUTHOR]

Background The positive predictive value of tuberculin skin test and current generation interferon gamma release assays are very low leading to high numbers needed to treat. Therefore, it is critical to identify new biomarkers with high predictive accuracy to identify individuals bearing high risk of progression to active tuberculosis (TB). Methods We used stored QuantiFERON supernatants from 14 household contacts of index TB patients who developed incident active TB during a 2-year follow-up and 20 age and sex-matched non-progressors. The supernatants were tested for an expanded panel of 45 cytokines, chemokines, and growth factors using the Luminex Multiplex Array kit. Results We found significant differences in the levels of TB-antigen induced production of several analytes between progressors and non-progressors. Dominance analysis identified 15 key predictive biomarkers based on relative percentage importance. Principal component analysis revealed that these biomarkers could robustly distinguish between the 2 groups. Receiver operating characteristic analysis identified interferon-γ inducible protein (IP)-10, chemokine ligand (CCL)19, interferon (IFN)-γ, interleukin (IL)-1ra, CCL3, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as the most promising predictive markers, with area under the curve (AUC) ≥90. IP-10/CCL19 ratio exhibited maximum sensitivity and specificity (100%) for predicting progression. Through Classification and Regression Tree analysis, a cutoff of 0.24 for IP-10/CCL19 ratio was found to be ideal for predicting short-term risk of progression to TB disease with a positive predictive value of 100 (95% confidence interval [CI] 85.8–100). Conclusions The biomarkers identified in this study will pave way for the development of a more accurate test that can identify individuals at high risk for immediate progression to TB disease for targeted intervention. [ABSTRACT FROM AUTHOR]

BACKGROUND / OBJECTIVES:Helminth infections are known to influence T cell responses in latent tuberculosis (LTBI). Whether helminth infections also modulate B cell responses in helminth-tuberculosis co-infection is not known. METHODS:We assessed Mycobacterium tuberculosis (Mtb)-antigen specific IgM and IgG levels, circulating levels of the B cell growth factors, BAFF and APRIL and the absolute numbers of the various B cell subsets in individuals with LTBI, LTBI with coincident Strongyloides stercoralis (Ss) infection (LTBI/Ss) and in those with Ss infection alone (Ss). We also measured the above-mentioned parameters in the LTBI-Ss group after anthelmintic therapy. RESULTS:Our data reveal that LTBI-Ss exhibit significantly diminished levels of Mtb-specific IgM and IgG, BAFF and APRIL levels in comparison to those with LTBI. Similarly, those with LTBI-Ss had significantly diminished numbers of all B cell subsets (naïve, immature, classical memory, activated memory, atypical memory and plasma cells) compared to those with LTBI. There was a positive correlation between Mtb-antigen specific IgM and IgG levels and BAFF and APRIL levels that were in turn related to the numbers of activated memory B cells, atypical memory B cells and plasma cells. Finally, anthelmintic treatment resulted in significantly increased levels of Mtb-antigen specific IgM and IgG levels and the numbers of each of the B cell subsets. CONCLUSIONS:Our data, therefore, reveal that Ss infection is associated with significant modulation of Mtb-specific antibody responses, the levels of B cell growth factors and the numbers of B cells (and their component subsets).

Despite marked improvement in the quality of lives across the globe, more than 2 million individuals in socioeconomically disadvantaged environments remain infected by helminth (worm) parasites. Owing to the longevity of the worms and paucity of immunologic controls, these parasites survive for long periods within the bloodstream, lymphatics, and gastrointestinal tract resulting in pathologic conditions such as anemia, cirrhosis, and lymphatic filariasis. Despite infection, an asymptomatic state may be maintained by the host immunoregulatory environment, which involves multiple levels of regulatory cells and cytokines; a breakdown of this regulation is observed in pathological disease. The role of TLR expression and function in relation to intracellular parasites has been documented but limited studies are available for multicellular helminth parasites. In this review, we discuss the unique and shared host effector mechanisms elicited by systemic helminth parasites and their derived products, including the role of TLRs and sphingolipids. Understanding and exploiting the interactions between these parasites and the host regulatory network are likely to highlight new strategies to control both infectious and immunological diseases.

Parasitic helminth worms, such as Schistosomamansoni, are endemic in regions with a high prevalence of tuberculosis (TB) among the population. Human studies suggest that helminth coinfections contribute to increased TB susceptibility and increased rates of TB reactivation. Prevailing models suggest that T helper type 2 (Th2) responses induced by helminth infection impair Th1 immune responses and thereby limit Mycobacterium tuberculosis (Mtb) control. Using a pulmonary mouse model of Mtb infection, we demonstrated that S. mansoni coinfection or immunization with S. mansoni egg antigens can reversibly impair Mtb-specific T cell responses without affecting macrophage-mediated Mtb control. Instead, S. mansoni infection resulted in accumulation of high arginase-1-expressing macrophages in the lung, which formed type 2 granulomas and exacerbated inflammation in Mtb-infected mice. Treatment of coinfected animals with an antihelminthic improved Mtb-specific Th1 responses and reduced disease severity. In a genetically diverse mouse population infected with Mtb, enhanced arginase-1 activity was associated with increased lung inflammation. Moreover, in patients with pulmonary TB, lung damage correlated with increased serum activity of arginase-1, which was elevated in TB patients coinfected with helminths. Together, our data indicate that helminth coinfection induces arginase-1-expressing type 2 granulomas, thereby increasing inflammation and TB disease severity. These results also provide insight into the mechanisms by which helminth coinfections drive increased susceptibility, disease progression, and severity in TB., Introduction About one-third of the world's population is infected with Mycobacterium tuberculosis (Mtb), leading to 1.4 million deaths and 8.8 million new reported cases of pulmonary tuberculosis (TB) every year [...]

Th9 cells are a subset of CD4+ T cells that express the protoypical cytokine, IL-9. Th9 cells are known to effect protective immunity in animal models of intestinal helminth infections. However, the role of Th9 cells in human intestinal helminth infections has never been examined.To examine the role of Th9 cells in Strongyloidis stercoralis (Ss), a common intestinal helminth infection, we compared the frequency of Th9 expressing IL-9 either singly (mono-functional) or co-expressing IL-4 or IL-10 (dual-functional) in Ss-infected individuals (INF) to frequencies in uninfected (UN) individuals.INF individuals exhibited a significant increase in the spontaneously expressed and/or antigen specific frequencies of both mono- and dual-functional Th9 cells as well as Th2 cells expressing IL-9 compared to UN. The differences in Th9 induction between INF and UN individuals was predominantly antigen-specific as the differences were no longer seen following control antigen or mitogen stimulation. In addition, the increased frequency of Th9 cells in response to parasite antigens was dependent on IL-10 and TGFx since neutralization of either of these cytokines resulted in diminished Th9 frequencies. Finally, following successful treatment of Ss infection, the frequencies of antigen-specific Th9 cells diminished in INF individuals, suggesting a role for the Th9 response in active Ss infection. Moreover, IL-9 levels in whole blood culture supernatants following Ss antigen stimulation were higher in INF compared to UN individuals.Thus, Ss infection is characterized by an IL-10- and TGFβ dependent expansion of Th9 cells, an expansion found to reversible by anti-helmintic treatment.

Tissue invasive helminth infections and tuberculosis (TB) are co-endemic in many parts of the world and can trigger immune responses that might antagonize each other. We have previously shown that helminth infections modulate the Th1 and Th17 responses to mycobacterial-antigens in latent TB. To determine whether helminth infections modulate antigen-specific and non-specific immune responses in active pulmonary TB, we examined CD4(+) and CD8(+) T cell responses as well as the systemic (plasma) cytokine levels in individuals with pulmonary TB with or without two distinct helminth infections-Wuchereria bancrofti and Strongyloides stercoralis infection. By analyzing the frequencies of Th1 and Th17 CD4(+) and CD8(+) T cells and their component subsets (including multifunctional cells), we report a significant diminution in the mycobacterial-specific frequencies of mono- and multi-functional CD4(+) Th1 and (to a lesser extent) Th17 cells when concomitant filarial or Strongyloides infection occurs. The impairment in CD4(+) and CD8(+) T cell cytokine responses was antigen-specific as polyclonal activated T cell frequencies were equivalent irrespective of helminth infection status. This diminution in T cell responses was also reflected in diminished circulating levels of Th1 (IFN-γ, TNF-α and IL-2)- and Th17 (IL-17A and IL-17F)-associated cytokines. Finally, we demonstrate that for the filarial co-infections at least, this diminished frequency of multifunctional CD4(+) T cell responses was partially dependent on IL-10 as IL-10 blockade significantly increased the frequencies of CD4(+) Th1 cells. Thus, co-existent helminth infection is associated with an IL-10 mediated (for filarial infection) profound inhibition of antigen-specific CD4(+) T cell responses as well as protective systemic cytokine responses in active pulmonary TB.

Lymphatic filariasis (LF) is known to be associated with an increased production of IL-10. The role of the other IL-10 family members in the pathogenesis of infection and/or disease is not known.We examined the expression patterns of IL-10 family members--IL-19, IL-24 and IL-26 in LF. We demonstrate that both CD4+ and CD8+ T cells express IL-19, IL-24 and IL-26 and that the frequency of CD4+ T cells expressing IL-19 and IL-24 (as well as IL-10) is significantly increased at baseline and following filarial antigen stimulation in patients with LF in comparison to individuals with filarial lymphedema and uninfected individuals. This CD4+ T cell expression pattern was associated with increased production of IL-19 and IL-24 by filarial-antigen stimulated PBMC. Moreover, the frequency of CD4+ and CD8+ T cells expressing IL-26 was significantly increased following filarial antigen stimulation in filarial lymphedema individuals. Interestingly, IL-10 blockade resulted in diminished frequencies of IL-19+ and IL-24+ T cells, whereas the addition of recombinant IL-10 resulted in significantly increased frequency of IL-19+ and IL-24+ T cells as well as significantly up regulated IL-19 and IL-24 gene expression, suggesting that IL-10 regulates IL-19 and IL-24 expression in T cells. In addition, IL-1β and IL-23 blockade also induced a diminution in the frequency of IL-19+ and IL-24+ T cells, indicating a novel role for these cytokines in the induction of IL-19 and IL-24 expressing T cells. Finally, elimination of infection resulted in significantly decreased frequencies of antigen - specific CD4+ T cells expressing IL-10, IL-19 and IL-24.Our findings, therefore, suggest that IL-19 and IL-24 are associated with the regulation of immune responses in active filarial infection and potentially with protection against development of pathology, while IL-26 is predominantly associated with pathology in LF.

BackgroundTwo different Th2 subsets have been defined recently on the basis of IL-5 expression - an IL-5(+)Th2 subset and an IL-5(-)Th2 subset in the setting of allergy. However, the role of these newly described CD4(+) T cells subpopulations has not been explored in other contexts.MethodsTo study the role of the Th2 subpopulation in a chronic, tissue invasive parasitic infection (lymphatic filariasis), we examined the frequency of IL-5(+)IL-4(+)IL-13(+) CD4(+) T cells and IL-5(-)IL-4 IL-13(+) CD4(+) T cells in asymptomatic, infected individuals (INF) and compared them to frequencies (Fo) in filarial-uninfected (UN) individuals and to those with filarial lymphedema (CP).ResultsINF individuals exhibited a significant increase in the spontaneously expressed and antigen-induced Fo of both Th2 subpopulations compared to the UN and CP. Interestingly, there was a positive correlation between the Fo of IL-5(+)Th2 cells and the absolute eosinophil and neutrophil counts; in addition there was a positive correlation between the frequency of the CD4(+)IL-5(-)Th2 subpopulation and the levels of parasite antigen - specific IgE and IgG4 in INF individuals. Moreover, blockade of IL-10 and/or TGFβ demonstrated that each of these 2 regulatory cytokines exert opposite effects on the different Th2 subsets. Finally, in those INF individuals cured of infection by anti-filarial therapy, there was a significantly decreased Fo of both Th2 subsets.ConclusionsOur findings suggest that both IL-5(+) and IL-5(-)Th2 cells play an important role in the regulation of immune responses in filarial infection and that these two Th2 subpopulations may be regulated by different cytokine-receptor mediated processes.

Microbial translocation (MT) is the process by which microbes or microbial products translocate from the intestine to the systemic circulation. MT is a common cause of systemic immune activation in HIV infection and is associated with reduced frequencies of CD4(+) T cells; no data exist, however, on the role of MT in intestinal helminth infections.We measured the plasma levels of MT markers, acute-phase proteins, and pro- and anti-inflammatory cytokines in individuals with or without hookworm infections. We also estimated the absolute counts of CD4(+) and CD8(+) T cells as well as the frequencies of memory T cell and dendritic cell subsets. Finally, we also measured the levels of all of these parameters in a subset of individuals following treatment of hookworm infection.Our data suggest that hookworm infection is characterized by increased levels of markers associated with MT but not acute-phase proteins nor pro-inflammatory cytokines. Hookworm infections were also associated with increased levels of the anti-inflammatory cytokine--IL-10, which was positively correlated with levels of lipopolysaccharide (LPS). In addition, MT was associated with decreased numbers of CD8(+) T cells and diminished frequencies of particular dendritic cell subsets. Antihelmintic treatment of hookworm infection resulted in reversal of some of the hematologic and microbiologic alterations.Our data provide compelling evidence for MT in a human intestinal helminth infection and its association with perturbations in the T cell and antigen-presenting cell compartments of the immune system. Our data also reveal that at least one dominant counter-regulatory mechanism i.e. increased IL-10 production might potentially protect against systemic immune activation in hookworm infections.

Infection with Wuchereria bancrofti can cause severe disease characterized by subcutaneous fibrosis and extracellular matrix remodeling. Matrix metalloproteinases (MMPs) are a family of enzymes governing extracellular remodeling by regulating cellular homeostasis, inflammation, and tissue reorganization, while tissue-inhibitors of metalloproteinases (TIMPs) are endogenous regulators of MMPs. Homeostatic as well as inflammation-induced balance between MMPs and TIMPs is considered critical in mediating tissue pathology.To elucidate the role of MMPs and TIMPs in filarial pathology, we compared the plasma levels of a panel of MMPs, TIMPs, other pro-fibrotic factors, and cytokines in individuals with chronic filarial pathology with (CP Ag+) or without (CP Ag-) active infection to those with clinically asymptomatic infections (INF) and in those without infection (endemic normal [EN]). Markers of pathogenesis were delineated based on comparisons between the two actively infected groups (CP Ag+ compared to INF) and those without active infection (CP Ag- compared to EN).Our data reveal that an increase in circulating levels of MMPs and TIMPs is characteristic of the filarial disease process per se and not of active infection; however, filarial disease with active infection is specifically associated with increased ratios of MMP1/TIMP4 and MMP8/TIMP4 as well as with pro-fibrotic cytokines (IL-5, IL-13 and TGF-β). Our data therefore suggest that while filarial lymphatic disease is characterized by a non-specific increase in plasma MMPs and TIMPs, the balance between MMPs and TIMPs is an important factor in regulating tissue pathology during active infection.