RESUMO
COVID-19 infection not only profoundly impacts the detection of tuberculosis infection (Tbc) but also affects modality in tuberculosis patient immune response. It is important to determine immune response alterations in latent tuberculosis infection as well as in SARS-CoV-2-infected tuberculosis patients. Such changes may have underlying effects on the development and course of further tuberculosis. Here, we aimed to review the characteristics of immune response in TB patients or convalescent COVID-19 patients with latent TB infection (LTBI). MATERIALS AND METHODS: We analyzed the features of immune response in tuberculosis and COVID-19 patients. For this, we analyzed publications released from December 2019 to March 2023; those which were published in accessible international databases ("Medline", "PubMed", "Scopus") and with keywords such as "COVID-19", "SARS-CoV-2", "tuberculosis", "pulmonary tuberculosis", "latent tuberculosis infection", "Treg", "follicular Treg", and "Treg subsets", we considered. RESULTS: Through our analysis, we found that tuberculosis patients who had been infected with COVID-19 previously and elevated Th1 and Th2 cell levels. High levels of Th1 and Th2 cells may serve as a positive marker, characterizing activated immune response during TB infection. COVID-19 or post-COVID-19 subjects showed decreased Th17 levels, indicating a lack of tuberculosis development. Moreover, the typical course of tuberculosis is associated with an increase in Treg level, but COVID-19 contributes to a hyperinflammatory response. CONCLUSION: According to the data obtained, the course of tuberculosis proceeds in a dissimilar way due to the distinct immune response, elicited by SARS-CoV-2. Importantly, the development of active tuberculosis with a severe course is associated with a decline in Treg levels. Both pathogens lead to disturbed immune responses, increasing the risk of developing severe TB. The insights and findings of this paper may be used to improve the future management of individuals with latent and active tuberculosis.
RESUMO
Background: The WHO strategy for eradication of tuberculosis (TB) by 2035 (The End TB Strategy) is aimed at an early and precise diagnosis and subsequent effective treatment of TB patients. Currently, there is no gold standard for the diagnosis of latent TB infection. This study evaluated the diagnostic capabilities of a new intradermal test using recombinant TB allergen (Diaskintest) compared with tuberculin skin test (TST) and commercial TB interferon-gamma release assays (IGRAs). Methods: A post-hoc data analysis that involved examining 860 HIV-negative, bacillus Calmette-Guérin (BCG)-vaccinated persons aged 1-65 years who visited the TB health-care institutions of Saint Petersburg to rule out or confirm an active TB was conducted from 2011 to 2016. Results: A high degree of consistency of the Diaskintest results with the enzyme-linked immunospot and QuantiFERON-TB Gold In-Tube test (ELISPOT and QFT) results was observed in the examined pediatric population (n = 696), with a Diaskintest cutoff ≥5 mm: the kappa consistency indices were 1.000 and 0.937, for ELISPOT and QFT, respectively. A high sensitivity of Diaskintest, comparable with the IGRA tests, was observed in patients with a confirmed TB diagnosis in all age groups. The sensitivity of Diaskintest in patients of the TB/MTB + group aged 18 years and older was 88.7%; of ELISPOT, 90.6%; of QFT, 87.0%. The conducted analysis has shown a high concordance of results of the commercial TB tests in adult HIV-negative patients (n = 164) with a Diaskintest cutoff ≥5 mm: the kappa indices were 0.805 and 0.636 (Diaskintest vs. ELISPOT and QFT, respectively) among BCG-vaccinated people. Conclusion: According to the WHO recommendations, replacing the TST by IGRAs is not recommended as a public health intervention in resource-constrained settings because the IGRA tests are more costly and technically complex to conduct than the TST. Diaskintest has comparable complexity to the TST and its performance is close to that of IGRA in a BCG-vaccinated population. Thus, our study demonstrates that replacing the TST by Diaskintest can be recommended as a public health intervention in resource-constrained and universal BCG vaccination settings.
