Citations

Abstract Introduction Screening individuals with latent tuberculosis infection (LTBI) from regions with varying TB endemicity is critical for global TB control. Immune responses to TB differ due to variations in exposure, immune adaptations, and environmental factors. This study evaluated antigen-specific immune responses in untreated LTBI individuals from low- and high-TB-endemic settings. Methods Peripheral blood mononuclear cells from untreated LTBI individuals from low-endemic (USA) and high-TB-endemic settings (Mexico) were stimulated with PPD, MTB300, ESAT-6/CFP-10 (RD1) peptides, mycobacterial glycopeptidolipids (GPL), and controls. We compare flow cytometric immune responses of T-cell intracellular cytokines and activation markers using non-parametric statistical methods. Results We studied age-matched, untreated LTBI individuals who tested IGRA(+)/TST(+) from low-TB-endemic (n = 18) and 18 healthcare workers from a high-TB-endemic settings. IGRA results showed no statistical differences across groups. The frequency of CD3+CD8+IFN-γ+HLA-DR+ and total CD3+TNF-α+ T cells after RD1 stimulation was significantly higher in the high-TB-endemic group (P < 0.05). Additionally, we observed significant increased frequencies in CD3/CD4+TNF-α+HLA-DR+ and CD8+TNF-α+HLA-DR+ T cells stimulated by GPL in the same group, probably associated with nontuberculous mycobacteria (NTM) exposures. Our findings suggest possible recent TB and NTM exposures in healthcare workers from a high-TB-endemic setting, resulted in increased antigen-specific adaptive TNF-α and IFN-γ producing T cells, which are important for pathogen control and immunity. Conclusion We found significant differences in antigen-specific cell immunity, including HLA-DR activated T-cells, a marker of recent antigen encounter, in individuals from a high-TB-endemic settings. These findings underscore the importance of settings-specific immune biomarkers for improving LTBI diagnostics, clinical management, and vaccination trials. Funding Source National Institute of Allergy and Infectious Diseases at the National Institutes of Health Topic Categories Immune Mechanisms of Human Disease (HUM)

Purpose Mycobacterium avium complex lung disease (MAC-LD) represents the most common form of nontuberculous mycobacterial lung infection, particularly affecting women and older adults. Clinical management remains challenging, including prediction and differentiation between progressive and non-progressive disease. Overexpression of PD-1 pathways have been reported in progressive disease, and we hypothesize that PD-1 inhibition can restore antigen-specific immune responses detectable by FluoroSpot assay. Methods Peripheral blood mononuclear cells from 22 participants, including progressive and non-progressive MAC-LD patients, healthy controls, and individuals with latent tuberculosis infection (LTBI) were stimulated with nontuberculous mycobacteria and Mycobacterium tuberculosis antigens. Cytokine secretion of interferon-gamma (IFN-γ) and interleukin-2 (IL-2) were quantified using dual FluoroSpot assay, with and without PD-1 blockade. Results Progressive MAC-LD cases demonstrated significant increases in glycopeptidolipid (GPL)- and PPD-stimulated IFN-γ responses following PD-1 blockade, which was not seen in healthy controls, LTBI, or non-progressive MAC-LD patients. After GPL stimulation and in the presence of anti-PD-1, the number of IFN-γ responses increased from 25% to 75% in samples from progressive MAC-LD patients. This supports an association between PD-1–mediated T-cell dysfunction and disease progression. Mycobacterial MTB300 peptide pool antigen failed to discriminate MAC-LD from healthy controls, underscoring antigen specificity. Conclusions Our pilot study demonstrates that IFN-γ FluoroSpot assays, particularly when combining GPL or PPD stimulation and PD-1 inhibition, may help identify progressive MAC-LD. These findings also support other studies reporting that immune checkpoint dysregulation can be present in some patients with progressive and severe MAC-LD patients. Additional studies are warranted to determine its pathogenic role.

Introduction Asymptomatic individuals with negative Interferon-γ release assay (IGRA) and tuberculin skin test (TST) results are often labeled as tuberculosis-unexposed individuals. We hypothesize that flow cytometric (FC) detection of antigen-stimulated T-cells in peripheral blood can differentiate IGRA(-)/TST(-) individuals with and without prior potential M. tuberculosis (Mtb) exposure. Methods We used FC multiparameter profiling of T-cell activation markers in TST/IGRA-negative individuals at risk for Mtb exposure and in unexposed controls. Results We studied 54 IGRA(-)/TST(-) subjects, including 27 individuals at risk for prior Mtb exposure. While quantitative IGRA results were negative in all patients, FC profiling of CD3/CD4 + IFN-γ + HLA-DR + T-cells after stimulation with a pool of Mtb-specific region of difference-1 (RD1) peptides, mycobacterial (PPD and MTB300), or Candida antigens, statistically differentiated between unexposed and potentially exposed individuals (P<0.05). ROC analysis showed PPD and RD1 peptides responses had AUCs >0.7 (sensitivity of 55.5–74% and specificity of 66.6–85.1%). The presence of a polyfunctional RD1-reactive CD3/CD8 + IFN-γ + TNF-α + T-cell subset also significantly differentiated these groups (AUC 0.66). Other T-cell markers demonstrated no significant differences. Conclusions FC detection of antigen-specific IFN-γ + HLA-DR + CD4+T-cells and IFN-γ + TNF-α + CD8 + T-cells can differentiate IGRA(-)/TST(-) individuals at risk of Mtb exposure from unexposed controls. Further validation is needed to determine whether this immunoprofiling approach can improve detection of Mtb infections and identification of unexposed individuals for future biomarker studies and vaccine trails.

Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs), with acute interstitial nephritis (ICI-AIN) being the most common irAE. While the exact mechanism remains unclear, upregulation of IFN-γ and TNF-α pathways has been implicated. This study used a humanized chimeric PD-1/PD-L1 mouse model to assess renal effects of ICIs, alone or combined with proinflammatory cytokines, and to test if selective TNF-α blockade could prevent ICI-AIN. Mice were randomly divided into 4 experimental groups: Control, ICI-Only, ICI-Cytokines (ICI-Cyt), and ICI-Block (ICI-TNF-α blockade). Renal function and cytokine profiles were assessed, while kidney tissue was analyzed using microscopy and single-cell RNA-seq. Histology revealed increased renal infiltration of CD4 + /CD8 + T cells in ICI-treated groups and decreased TNF-α expression following TNF-α blockade. Additionally, kidney tissue ELISA demonstrated reduced IFN-γ levels following TNF-α blockade. Plasma IL-6, MCP-1, and TNF-α were lower in ICI-Block mice. Single-cell RNA-seq revealed shifts in immune cell populations and genes of interest including Bcl2a1 , Icos , Il18r1 , Ccr2 , and Jaml . This humanized model replicates ICI-AIN key features, revealing a synergistic role of ICIs and proinflammatory cytokines. TNF-α blockade demonstrated protective effects, supporting its potential role in mitigating the risk of ICI-AIN.

Glioblastoma (GBM) is the most frequent and aggressive malignant primary tumor of the central nervous system in adults, with an incidence of 3.23 per 100,000 people. Despite the existence of various therapeutic approaches, the absence of a cure and the unfavorable prognosis persist for this neoplasm, with a median survival of approximately 8-15 months and a 5-year survival rate of 6.9%. In this review, we address the epidemiology, histopathology, molecular characteristics, and treatment of GBM. We highlight the relationship of GBM with the microenvironment in the lateral ventricle wall and the cerebrospinal fluid. The location of GBM in this region results in more aggressive tumors and shorter life expectancy for patients. Understanding the malignancy mechanisms that hinder remission, treatment, and positive prognosis opens the possibility of improving diagnostic and therapeutic interventions against GBM.