Cigarette smoke has a negative impact onM. tuberculosisimmune response

Abstract

<b>Objectives:</b> To investigate the immune response against <i>M. tuberculosis (MTB)</i> by Interferon Gamma Release Assays (IGRAs) in Tuberculosis (TB) and Latent TB Infected (LTBI) patients exposed to cigarette smoke. <b>Methods:</b> A cross sectional study from two clinics in Barcelona. Subjects included were: (i) 216 active pulmonary TB, (ii) 309 asymptomatic contact tracing individuals. At first visit blood was collected for IGRAs. The impact of cigarette smoke on MTB immune response was analyzed as the median of IFN-γ secreted (UI/mL) in QFN-G-IT and as the number (median) of T-cells producing IFN-γ [spot forming cells (SFC)] in T-SPOT.TB. <b>Results:</b> False-negative results in TB patients were higher in smokers (aOR:4.42; p&lt;0.0001). Smoker contacts had higher LTBI prevalence (aOR:11.98; p&lt;0.001). In non smoker TB patients the immune response [QFN.GIT: 3.37 (1.4-9.5); T-SPOT.TB: 75.5 (30.0-134.0)] was higher (p&lt;0.0001) than in smokers [(QFN.GIT: 0.93 (0.2-3.3); T-SPOT.TB: 38.5 (13.0-99.0)]. In LTBI contacts the IFN-γ response was higher (p&lt;0.05) in non smokers [QFN.GIT: 4.6 (0.8-10.6);T-SPOT.TB: 50.0 (25.0-144.0)] than in smokers [QFN.GIT: 1.3 (0.5-4.0; T-SPOT.TB: 31.0 (17.0-53.0)]. A negative dose-dependent relation was observed between the smoking quantity and the IFN-γ response analyzed by QFN-G-IT and T-SPOT.TB for active TB patients and contacts with LTBI. <b>Conclusions:</b> Tobacco exposure was associated with IGRAs false-negative results in TB patients and was an independent risk factor for LTBI acquisition. A less IFN-γ response was observed in smokers than non-smokers. An increment on tobacco smoking produces a reduction on immune responses observed by both IGRAs. PII –Tabaquismo. 2013 SEPAR grant.