Higher interferon gamma response to mycobacterium tuberculosis antigen is associated with less severe COVID-19

Document Type

Article

Department

Pathology and Laboratory Medicine

Abstract

Background: Mycobacterium tuberculosis (Mtb) and SARS-CoV-2 are both respiratory pathogens and their interaction in host is not well understood, especially in case of latent tuberculosis (LTBi). LTBi is known to alter host immune response and its impact on outcome of COVID-19 disease is still under debate.
Objectives: This study was designed to compare the interferon-gamma (IFN-γ) response against Mtb antigens in healthy individuals and COVID-19 patients and its association with disease severity. We also compared IgG response against receptor-binding domain (RBD) protein of SARS-CoV-2 virus in the presence or absence of LTBi.
Methods: A total of 275 participants as 147 healthy controls and 128 COVID-19 patients were recruited. COVID-19 patients were categorized according to the WHO ordinary scale in 1–3 (ambulatory: n = 103) or 4–7 (hospitalized: n = 25) disease severity. LTBi was screened through X DOT TB-an ELISPOT assay using whole blood. IFN-γ response was compared as spot forming units in PBMCs of X DOT TB assay supernatants. Anti-RBD and anti-Rubella IgG levels were measured through ELISA.
Results: We found the frequency of LTBi was lower (18%) among COVID-19 than in the HC group (32%; P < 0.001). All LTBi-positive COVID-19 had mild disease. COVID-19 frequency and severity increased with age as well as with comorbidities, independently of the LTBi status (P < 0.05). Levels of Mtb-specific IFN-g secreting cells were lower in the COVID-19 than in healthy controls (HC) individuals (P = 0.04). Severe COVID-19 cases showed lower IFN-γ responses to Mtb than those with mild disease (P = 0.02). The anti-Sars-Cov-2 RBD IgG levels did not differ between LTBi positive or negative individuals (P = NS). Anti-Rubella IgG titers in LTBi positive or negative individuals were similar (P = NS).
Conclusion: Our study has shown low detection of latent TB in COVID-19 individuals as compared to healthy controls. We further observed no detection of LTBi in hospitalized COVID-19 which is suggestive of downregulated T-cell response in severe COVID-19. There was no difference in IgG response against SARS-Cov-2 RBD or Rubella in the presence or absence of LTBi. Further studies are required to study the underlying differential molecular pathways regulated in these individuals.

Comments

Volume and issue are not provided by the author/publisher.

Publication (Name of Journal)

International Journal of Mycobacteriology

DOI

10.4103/ijmy.ijmy_82_24

Link to Full Text

Share

COinS