Multi-Dimensionality Immunophenotyping Analyses of MAIT Cells Expressing Th1/Th17 Cytokines and Cytotoxic Markers in Latent Tuberculosis Diabetes Comorbidity

Mucosal-associated invariant T (MAIT) cells are innate like, and play a major role in restricting disease caused by Mycobacterium tuberculosis (Mtb) disease before the activation of antigen-specific T cells. Additionally, the potential link and synergistic function between diabetes mellitus (DM) and tuberculosis (TB) has been recognized for a long time. However, the role of MAIT cells in latent TB (LTB) DM or pre-DM (PDM) and non-DM (NDM) comorbidities is not known. Hence, we examined the frequencies (represented as geometric means, GM) of unstimulated (UNS), mycobacterial (purified protein derivative (PPD) and whole-cell lysate (WCL)), and positive control (phorbol myristate acetate (P)/ionomycin (I)) antigen stimulated MAIT cells expressing Th1 (IFNγ, TNFα, and IL-2), Th17 (IL-17A, IL-17F, and IL-22), and cytotoxic (perforin (PFN), granzyme (GZE B), and granulysin (GNLSN)) markers in LTB comorbidities by uniform manifold approximation (UMAP) and flow cytometry. We also performed a correlation analysis of Th1/Th17 cytokines and cytotoxic markers with HbA1c, TST, and BMI, and diverse hematological and biochemical parameters. The UMAP analysis demonstrated that the percentage of MAIT cells was higher; T helper (Th)1 cytokine and cytotoxic (PFN) markers expressions were different in LTB-DM and PDM individuals in comparison to the LTB-NDM group on UMAP. Similarly, no significant difference was observed in the geometric means (GM) of MAIT cells expressing Th1, Th17, and cytotoxic markers between the study population under UNS conditions. In mycobacterial antigen stimulation, the GM of Th1 (IFNγ (PPD and WCL), TNFα (PPD and WCL), and IL-2 (PPD)), and Th17 (IL-17A, IL-17F, and IL-22 (PPD and/or WCL)) cytokines were significantly elevated and cytotoxic markers (PFN, GZE B, and GNLSN (PPD and WCL)) were significantly reduced in the LTB-DM and/or PDM group compared to the LTB-NDM group. Some of the Th1/Th17 cytokines and cytotoxic markers were significantly correlated with the parameters analyzed. Overall, we found that different Th1 cytokines and cytotoxic marker population clusters and increased Th1 and Th17 (IL-17A, IL-22) cytokines and diminished cytotoxic markers expressing MAIT cells are associated with LTB-PDM and DM comorbidities.

Improving screening and management of latent tuberculosis infection: development and evaluation of latent tuberculosis infection primary care model

Background In Australia, demand for specialist infectious diseases services exceeds capacity to provide timely management of latent tuberculosis infection (LTBI) in areas of high refugee and asylum seeker settlement. A model for treating LTBI patients in primary care has been developed and piloted in a refugee-focused primary health service (Monash Health Refugee Health and Wellbeing [MHRHW]) and a universal primary care clinic. This study reports on the development and evaluation of the model, focusing on the model feasibility, and barriers and enablers to its success. Methods A convergent mix-methods design was used to evaluate the model for treating LTBI patients in primary care, where a prospective cohort study of patients commencing treatment either at MHRHW or the universal primary care clinic determined the model feasibility, while focus groups with clinicians directly involved in treating these patients explored barriers and enablers to sustainability and success of the model. Results From January 2017 to April 2018, 65 patients with confirmed LTBI presented at participating clinics. Treatment was accepted by 31 (48%) patients, of whom 15(48%) were treated at MHRHW and 16 (52%) at the universal primary care clinic. The 6-months’ treatment completion rate was higher at MHRHW compared to the universal primary care clinic (14 (93%) compared to 9 (56%) respectively, p = 0.0373). Reasons for non-completion included adverse reaction, opting out and relocation. At the completion of the pilot, 15 clinicians participated in two focus groups. Clinicians identified barriers and enablers for successful LTBI management at patient, provider, organisational and clinical levels. While barriers for treatment completion and adherence were consistent across the two pilot sites, enablers, such as resources to facilitate patient education and follow-up, were available only at MHRHW. Conclusion Screening and management of LTBI patients can be achieved within the primary care setting, considerate of barriers and enablers at patient, provider, organisational and clinical levels. Upscaling of a primary care response to the management of LTBI will require supporting primary care clinics with resources to employ dedicated clinical staff for patient education, follow-up communication and monitoring medication adherence.

Latent tuberculosis and COVID-19 disease

Since the start of the COVID-19 pandemic in 2020, there has been chaos in the world. With the COVID-19 cases rising, many other medical diseases have been ignored and not prioritized. One of these crucial diseases is Tuberculosis (TB). TB is a highly infectious bacterial respiratory disease. Every year there are millions of cases that are registered all around the world. TB is seen in two forms, an active and a latent form. In both of the states, the individual with TB is immunocompromised. This is of great importance, as COVID-19 is known to readily infect individuals in an immunocompromised state more than those with a healthy immune system. Although a little investigation about coexisting infections with COVID-19 and TB is conducted, it is important to consider many factors that can be beneficial to help treat these patients with both conditions effectively and promptly. A few of these factors are pathophysiological relation, diagnostic measurements, effects of each condition on the other, and approaches to treatment. Through a literature review of available information, we summarized the knowledge regarding the correlation between Latent TB infection and COVID-19 infection. The main objective of this publication is to provide a brief overview of how the two conditions overlap with one another. The article also provides a clinical review of how to approach these two conditions in a scenario where an individual is found to be infected with both Latent TB and COVID-19.

GIVE Statistic for Goodness of Fit in Instrumental Variables Models with Application to COVID Data

Since COVID-19 outbreak, scientists have been interested to know whether there is any impact of the Bacillus Calmette-Guerin (BCG) vaccine against COVID-19 mortality or not. It becomes more relevant as a large population in the world may have latent tuberculosis infection (LTBI), for which a person may not have active tuberculosis but persistent immune responses stimulated by Mycobacterium tuberculosis antigens, and that means, both LTBI and BCG generate immunity against COVID-19. In order to understand the relationship between LTBI and COVID-19 mortality, this article proposes a measure of goodness of fit, viz., Goodness of Instrumental Variable Estimates (GIVE) statistic, of a model obtained by Instrumental Variables estimation. The GIVE helps in finding the appropriate choice of instruments, which provides a better fitted model. In the course of study, the large sample properties of the GIVE statistic are investigated. As indicated before, the COVID-19 data is analysed using the GIVE statistic, and moreover, simulation studies are also conducted to show the usefulness of the GIVE statistic.

High prevalence of latent tuberculosis using the QuantiFERON-TB Gold Plus test in Takayasu arteritis

Objectives: This study aims to investigate latent tuberculosis using the QuantiFERON-TB Gold Plus method in patients with Takayasu arteritis (TA). Patients and methods: This case-control study included 22 patients with TA (3 males, 19 females; median age: 36.5 years; IQR, 32 to 50 years), 22 healthy individuals (3 males, 19 females; median age: 38.5 years; IQR, 32.5 to 50 years), and 66 patients with diffuse connective tissue diseases (DCTDs) (4 males, 62 females; median age: 41 years; IQR, 29.8 to 54 years). Two control groups were formed: (i) age- and sex-matched healthy individuals and (ii) patients with other DCTDs. Epidemiological data were collected, and the QFT-Plus test was performed. The QFT-plus positivity was compared among the groups. Results: A higher prevalence of QFT-Plus positive cases was observed in the TA group (8/22) than in the healthy control group (1/22) (p=0.020) or in the group with other DCTDs (3/66) (p=0.001). There was a statistically significant difference in the past pulmonary tuberculosis prevalence between the TA and DCTD groups (p=0.013). Conclusion: The prevalence of latent tuberculosis in TA patients (36.4%) was higher than that in both control groups and higher than the prevalence of latent tuberculosis among the general Brazilian population. Although a positive association was found, it is not possible to establish a direct cause-effect relationship. Given the increasing use of anti-cytokine therapies in TA, it is necessary to thoroughly screen patients with TA before initiating immunosuppressive therapy to avoid tuberculosis reactivation.