AUTHOR=Mendy Joseph , Jarju Sheikh , Heslop Rhiannon , Bojang Adama L. , Kampmann Beate , Sutherland Jayne S. 

TITLE=Changes in Mycobacterium tuberculosis-Specific Immunity With Influenza co-infection at Time of TB Diagnosis

JOURNAL=Frontiers in Immunology

VOLUME=Volume 9 - 2018

YEAR=2019

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.03093

DOI=10.3389/fimmu.2018.03093

ISSN=1664-3224

ABSTRACT=Background: Prior Influenza A viral (IAV) infection has been shown to increase susceptibility to tuberculosis (TB) and TB has also been shown to be a primary cause of death during pandemics, including the Spanish Influenza outbreak of 1918-1919. The majority of data has been obtained from mouse models, thus the aim of this study was to determine the impact of Flu co-infection on host immunity and disease severity in TB patients at diagnosis.  
Methods: Sputum from 282 patients with active TB were analysed for presence of FluA/FluB RNA at presentation using multiplex PCR. Sputum RNA was also analysed for Mycobacterium tuberculosis (Mtb) load using 16S RNA amplification. Supernatants from digested sputum and Mtb antigen-stimulated whole blood were analysed using multiplex cytokine arrays and PBMC were analysed for cytokine production from CD4+ T, CD8+ T and Mucosal Associated Invariant T cells (MAITs). 
Results: 12 (4.3%) of TB patients were found to have FluA or FluB viral RNA present in their sputum at the time of TB diagnosis. The TB/Flu co-infected patients had a significantly higher bacterial load compared to those with TB mono-infection (p=0.0026). They had lower levels of IL17A in ex vivo sputum (p=0.0275) and higher MCP-1 (CCL2) levels in the blood following PPD stimulation (p=0.0267). TB/Flu co-infected subjects had significantly higher IFN-γ+IL-17+CD4+ and IFN-γ+IL-17-CD8+ cells compared to TB mono-infected subjects. 
Conclusions: These data show that Flu co-infection at time of TB diagnosis is associated with a higher bacterial load and differential cellular and soluble profiles.  These findings show for the first time the impact of TB/Flu co-infection in a human cohort and support the potential benefit of Flu vaccination in TB-endemic settings.