65 research outputs found
Image_1.tiff
<p>Tuberculosis (TB) is still a global health concern, especially in resource-poor countries such as The Gambia. Defining protective immunity to TB is challenging: its pathogenesis is complex and involves several cellular components of the immune system. Recent works in vaccine development suggest important roles of the innate immunity in natural protection to TB, including natural killer (NK) cells. NK cells mediate cellular cytotoxicity and cytokine signaling in response to Mycobacterium tuberculosis (Mtb). NK cells can display specific memory-type markers to previous antigen exposure; thus, bridging innate and adaptive immunity. However, major knowledge gaps exist on the contribution of NK cells in protection against Mtb infection or TB. We performed a cross-sectional assessment of NK cells phenotype and function in four distinct groups of individuals: TB cases pre-treatment (n = 20) and post-treatment (n = 19), and household contacts with positive (n = 9) or negative (n = 18) tuberculin skin test (TST). While NK cells frequencies were similar between all groups, significant decreases in interferon-γ expression and degranulation were observed in NK cells from TB cases pre-treatment compared to post-treatment. Conversely, CD57 expression, a marker of advanced NK cells differentiation, was significantly lower in cases post-treatment compared to pre-treatment. Finally, NKG2C, an activation and imprinted-NK memory marker, was significantly increased in TST+ (latently infected) compared to TB cases pre-treatment and TST− (uninfected) individuals. The results of this study provide valuable insights into the role of NK cells in Mtb infection and TB disease, demonstrating potential markers for distinguishing between infection states and monitoring of TB treatment response.</p
Frequency distribution of smoothed tuberculin induration sizes (mm).
<p>Frequency distribution of smoothed tuberculin induration sizes (mm).</p
Frequency distribution of tuberculin induration sizes (mm) by residence in school children with a BCG scar present.
<p>10,679 of 13, 386 children, 79.8% had 0 mm induration and are not shown.</p
Prevalence of latent tuberculosis and annual risk of <i>M</i>. <i>tuberculosis</i> infection in Gambian schoolchildren aged 6–11 years using a 12mm cut-off point.
<p>95% Confidence Interval (95%CI)</p><p><sup>a</sup> Denominator, N does not include non-reactive TST</p><p><sup>b</sup> Adjusted for all other terms in the model</p><p>Prevalence of latent tuberculosis and annual risk of <i>M</i>. <i>tuberculosis</i> infection in Gambian schoolchildren aged 6–11 years using a 12mm cut-off point.</p
Frequency distribution of tuberculin induration sizes (mm) among Gambian School Children aged 6–11 years.
<p>Frequency distribution of tuberculin induration sizes (mm) among Gambian School Children aged 6–11 years.</p
Demographic, microbiologic and Mtb exposure characteristics of study participants.
<p><b>*</b> Fisher's exact test: p = 0.017 for proximity between TST<sup>+</sup> and PTST<sup>−</sup>. ns = not significant; TST<sup>+</sup> = TST positive; TSTC = TST converters; PTST<sup>−</sup> = persistently TST negative; na = not assessed; IQR = interquartile range.</p><p>Demographic, microbiologic and Mtb exposure characteristics of study participants.</p
Derivation of TST cut-off from mixture modelling of the frequencies of tuberculin indurations (mm).
<p>Derivation of TST cut-off from mixture modelling of the frequencies of tuberculin indurations (mm).</p
Frequency distribution of tuberculin induration sizes (mm) by residence in school children with a BCG scar absent.
<p>Footnote: 10,679 of 13, 386 children, 79.8% had 0 mm induration and are not shown.</p
Prevalence of latent tuberculosis and annual risk of <i>M</i>. <i>tuberculosis</i> infection in Gambian schoolchildren aged 6–11 years using a 17mm cut-off point.
<p>95% Confidence Interval (95%CI)</p><p><sup>a</sup> Denominator, N does not include non-reactive TST</p><p><sup>b</sup> Adjusted for all other terms in the model</p><p>Prevalence of latent tuberculosis and annual risk of <i>M</i>. <i>tuberculosis</i> infection in Gambian schoolchildren aged 6–11 years using a 17mm cut-off point.</p
- …