Biology subjects

Du Bruyn, E.

Publications and source records attributed to Du Bruyn, E..

3 recordsLinked to original sources

bioRxiv2022

Blood and site of disease inflammatory profiles differ in HIV-1-infected pericardial tuberculosis patients

ObjectivesTo better understand the pathogenesis of pericardial tuberculosis (PCTB), we sought to characterize the systemic inflammatory profile in HIV-1-infected participants with latent TB infection (LTBI), pulmonary TB (PTB) and PCTB. MethodsUsing Luminex, we measured 39 analytes in pericardial fluid (PCF) and paired plasma from 18 PCTB participants, and plasma from 16 LTBI and 20 PTB. Follow-up plasma samples were also obtained from PTB and PCTB participants. HLA-DR expression on Mtb-specific CD4 T cells was measured in baseline samples using flow cytometry. ResultsAssessment of the overall systemic inflammatory profile by principal component analysis showed that the inflammatory profile of active TB participants was distinct from the LTBI group, while PTB patients could not be distinguished from those with PCTB. In the LTBI group, 12 analytes showed a positive association with plasma HIV-1 viral load, and most of these associations were lost in the diseased groups. When comparing the inflammatory profile between PCF and paired blood, we found that the concentrations of most analytes (24/39) were elevated at site of disease. However, the inflammatory profile in PCF partially mirrored inflammatory events in the blood. After TB treatment completion, the overall plasma inflammatory profile reverted to those observed in the LTBI group. Lastly, HLA-DR expression showed the best performance for TB diagnosis compared to previously described biosignatures built from soluble markers. ConclusionOur results describe the inflammatory profile associated with PTB and PCTB and emphasize the potential role of HLA-DR as a promising biomarker for TB diagnosis.

immunology↗

bioRxiv2022

Phenotypic profile of Mycobacterium tuberculosis-specific CD4 T cell responses in HIV-positive patients who develop Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome

BackgroundTuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent complication of co-treatment for TB and HIV-1. We characterized Mtb-specific CD4 T cell phenotype and transcription factor profile associated with the development of TB-IRIS. MethodsWe examined the role of CD4 T-cell transcription factors in a murine model of mycobacterial IRIS. In humans, we compared longitudinally on antiretroviral therapy (ART) the magnitude, activation, transcription factor profile and cytotoxic potential of Mtb-specific CD4 T cells between TB-IRIS (n=25) and appropriate non-IRIS control patients (n=18) using flow cytometry. ResultsIn the murine model, CD4 T cell expression of Eomes, but not Tbet, was associated with experimentally induced IRIS. In patients, TB-IRIS onset was associated with the expansion of Mtb-specific IFN{gamma}+CD4 T cells (p=0.039). TB-IRIS patients had higher HLA-DR expression (p=0.016), but no differences in the expression of T-bet or Eomes were observed. At TB-IRIS onset, Eomes+Tbet+Mtb-specific IFN{gamma}+CD4+ T cells showed higher expression of Granzyme B in TB-IRIS patients (p=0.026). ConclusionWhile the murine model of MAC-IRIS suggests that Eomes+CD4 T cells underly IRIS, TB-IRIS was not associated with Eomes expression in patients. Mtb-specific IFN{gamma}+CD4 T cell responses in TB-IRIS patients are differentiated, highly activated and potentially cytotoxic.

immunology↗

bioRxiv2022

Profile of Mycobacterium tuberculosis-specific CD4 T cells at the site of disease and blood in pericardial tuberculosis

Our understanding of the immune response at the site of disease in extra-pulmonary tuberculosis (EPTB) is still limited. In this study, using flow cytometry, we defined the pericardial fluid (PCF) cellular composition and compared the phenotypic and functional profile of Mycobacterium tuberculosis (Mtb)-specific T cells between PCF and whole blood in 16 patients with pericardial TB (PCTB). We found that lymphocytes were the predominant cell type in PCF in PCTB, with a preferential influx of CD4 T cells. The frequencies of TNF- producing myeloid cells and Mtb-specific T cells were significantly higher in PCF compared to blood. Mtb-specific CD4 T cells in PCF exhibited a distinct phenotype compared to those in blood, with greater GrB expression and lower CD27 and KLRG1 expression. We observed no difference in the production IFN{gamma}, TNF or IL-2 by Mtb-specific CD4 T cells between the two compartments, but MIP-1{beta} production was lower in the PCF T cells. Bacterial loads in the PCF did not relate to the phenotype or function of Mtb-specific CD4 T cells. Upon anti-tubercular treatment completion, HLA-DR, Ki-67 and GrB expression was significantly decreased, and relative IL-2 production was increased in peripheral Mtb-specific CD4 T cells. Overall, using a novel and rapid experimental approach to measure T cell response ex vivo at site of disease, these results provide novel insight into molecular mechanisms and immunopathology at site of TB infection of the pericardium.

immunology↗