The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) pandemic has attracted interest because of its global rapid spread, clinical severity, high mortality rate and capacity to overwhelm healthcare systems [1, 2]. SARS-CoV-2 transmission occurs mainly through droplets, although surface contamination contributes and debate continues on aerosol transmission [3-5]. The disease is usually characterised by initial signs and symptoms [4-9] similar to those of related viral infections (e.g. influenza, SARS, Middle East respiratory syndrome) and tuberculosis (TB), although prognosis and complications sometimes differ. Experience with concomitant TB and COVID-19 is extremely limited. One case-control study of COVID-19 patients with interferon-γ release assay-confirmed TB infection [10] and a single case of TB with COVID-19 have been submitted to, but not yet published in, peer-reviewed journals [11]. In a recent analysis of 1217 consecutive respiratory specimens collected from COVID-19 patients (Mycobacterium tuberculosis was not tested), the authors concluded that higher rates of co-infection between SARS-CoV-2 and other respiratory pathogens can be expected [12]. The present study describes the first-ever global cohort of current or former TB patients (post-TB treatment sequelae) with COVID-19, recruited by the Global Tuberculosis Network (GTN) in eight countries and three continents. No analysis for determinants of outcome was attempted. The study is nested within the GTN project monitoring adverse drug reactions [13, 14] for which the coordinating centre has an ethics committee approval, alongside ethics clearance from participating centres according to respective national regulation [13, 14]. A specific nested database was created in collaboration with the eight countries reporting patients with TB and COVID-19; the remaining countries had not yet observed COVID-19 in their patients at the time this manuscript was written. Continuous variables, if not otherwise specified, are presented as medians with interquartile ranges. Overall, 49 consecutive patients with current or former TB and COVID-19 from 26 centres in Belgium (n=1), Brazil (Porto Alegre, Rio Grande do Sul State; n=1), France (n=12), Italy (n=17), Russia (Moscow Region; n=6), Singapore (n=1), Spain (n=10) and Switzerland (Vaud Canton; n=1) were recruited (dataset updated as of
SUMMARYLeptin, the 16 kDa product of the ob gene, is a an adipocyte-secreted hormone that centrally regulates weight. However, the physiological role of leptin is not limited to the regulation of food intake and energy expenditure, and leptin has a variety of effects in peripheral tissues, such as a regulatory role modulating the immune system. Thus, leptin receptor is expressed in human peripheral blood mononuclear cells, mediating the leptin stimulation of proliferation and activation , the production of proinflammatory cytokines from cultured monocytes, and the prevention of apoptotic death in serumdeprived monocytes. Because leptin can stimulate monocytes and the production of reactive oxygen species (ROS) are the result of monocyte activation, we investigated the effect of leptin on ROS production by human monocytes in vitro . Oxidative burst was measured by oxidation of the redox-sensitive dye 2 ¢ ,7 ¢ -dichlorofluorescein diacetate, and analysed by flow cytometry. We have found that stimulation with leptin produces oxygen radical formation by monocytes. This effect is dependent on the dose and maximal response is achieved at 10 n M leptin. Because HIV infection induces the production of ROS, we next investigated the effect of leptin on ROS production in monocytes from HIV-positive (HIV + ) subjects. We have also found that monocytes from HIV + subjects spontaneously produced increased amounts of free radicals. In contrast, leptin stimulation of monocytes from these patients partially inhibited the production of ROS. This effect of leptin was also dependent on the dose and maximal effect was achieved at 10 n M . The effect of leptin stimulating the production of ROS is consistent with the proinflammatory role in the immune system. On the other hand, the inhibitory effect on monocytes from HIV + subjects may be explained by the attenuation of the oxidative burst by a delayed activation of monocytes in a hyperinflammatory state.
A multicenter, comparative study was performed to determine the epidemiological, clinical, and prognostic differences between the diseases caused by Mycobacterium tuberculosis and Mycobacterium kansasii in human immunodeficiency virus (HIV)-infected patients. From 1 January 1995 through 31 December 1999, 25 HIVinfected patients received diagnoses of M. kansasii infection, and another 75 were selected as control subjects from among patients who had M. tuberculosis infection. Variables associated with M. tuberculosis disease in the multivariate analysis were previous intravenous drug use (odds ratio [OR], 8; 95% confidence interval [CI], 1.5-41.4) and interstitial radiologic pattern (OR, 12.7; 95% CI, 1.7-94.3). Variables associated with M. kansasii were previous diagnosis of acquired immunodeficiency syndrome (OR, 15.8; 95% CI, 4.2-59.6) and concomitant opportunistic infections (OR, 14.2; 95% CI, 2-105.7). Clinical and radiologic features were similar for both groups, but epidemiological characteristics and prognosis were different. M. kansasii disease was associated more closely with level of immunosuppression and progression of HIV infection than was disease caused by M. tuberculosis. Mycobacterium kansasii was first described in 1953 by Buhler and Pollak [1]. They named it "yellow bacillus." Its antigenic and clinical characteristics make it the mycobacterium most similar to Mycobacterium tuberculosis. M. kansasii was an unusual pathogen before the onset of the HIV epidemic [2]; its prevalence was 0.33
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