MTOR gene variants are associated with severe COVID-19 outcomes: A multicenter study.

BACKGROUND: The worst outcomes linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been attributed to the cytokine storm, which contributes significantly to the immunopathogenesis of the disease. The mammalian target of rapamycin (mTOR) pathway is essential for orchestrating innate immune cell defense including cytokine production and is dysregulated in severe Coronavirus Disease 2019 (COVID-19) individuals. The individual genetic background might play a role in the exacerbated immune response. OBJECTIVE: In this study, we aimed to investigate the association between MTOR genetic variants and COVID-19 outcomes. METHODS: This study enrolled groups of individuals with severe (n = 285) and mild (n = 207) COVID-19 from Brazilian states. The MTOR variants, rs1057079 and rs2536, were genotyped. A logistic regression analysis and Kaplan-Meier survival curves were performed. We applied a genotyping risk score to estimate the cumulative contribution of the risk alleles. Tumor necrosis factor (TNF) and interleukin-6 (IL-6) plasma levels were also measured. RESULTS: The T allele of the MTOR rs1057079 variant was associated with a higher likelihood of developing the most severe form of COVID-19. In addition, higher levels of IL-6 and COVID-19 death was linked to the T allele of the rs2536 variant. These variants exhibited a cumulative risk when inherited collectively. CONCLUSIONS: These results show a potential pathogenetic role of MTOR gene variants and may be useful for predicting severe outcomes following COVID-19 infection, resulting in a more effective allocation of health resources.

Early detection and persistent positivity of anti-Leishmania antibodies using a recombinant protein-based ELISA in naturally infected dogs in Brazil.

BACKGROUND: Visceral leishmaniasis (VL) is a zoonotic disease caused by Leishmania infantum, for which dogs constitute the main urban parasite reservoir. Control measures and the treatment of canine visceral leishmaniasis (CVL) are essential to reduce VL cases. Early and accurate detection of L. infantum-infected dogs is crucial to the success of VL control. To improve the serological detection of L. infantum-exposed dogs, we evaluated the early diagnosis capacity of a recombinant protein (rLci5) in an immunosorbent assay (ELISA) to detect naturally infected dogs. Additionally, we evaluated the persistence of the positive results obtained by rLci5 ELISA in comparison to other conventional diagnostic test methods. METHODS: Serum samples obtained from 48 L. infantum-infected dogs involved in a cohort study were evaluated using different diagnostic methods (qPCR, EIE-LVC, DPP-LVC and splenic culture). The results were compared to rLci5 ELISA to determine its capacity to diagnose L. infantum infection at earlier infection time points. The persistence of positive diagnostic test results was also compared for each dog evaluated. RESULTS: rLci5 ELISA presented higher rates of positive results at early time points compared to the other diagnostic tests employed in the cohort study, as early as 24 months prior to detection by other tests. rLci5 ELISA positivity was 52.1% (25/48) at baseline, while qPCR was 35.4% (17/48), DPP-LVC 27.1% (13/48), EIE-LVC 22.9% (11/48) and culture only 4.2% (2/48). In at least one of the time points of the 24-month cohort study, rLci5 ELISA was positive in 100% (48/48) of the dogs, versus 83% (40/48) for qPCR, 75% (36/48) for DPP-LVC, 65% (31/48) for EIE-LVC and 31% (15/48) for culture. Investigating clinical signs in association with diagnostic test positivity, rLci5 ELISA successfully detected CVL in 62.9% (95/151) of the clinical evaluations with a score of 0-3, 64.3% (45/70) with scores between 4 and 7, and 73.7% (14/19) with scores > 7, providing higher rates of positivity than all other methods evaluated. Moreover, rLci5 ELISA presented the greatest persistence with respect to test positivity: 45.8% of the dogs evaluated. CONCLUSION: Four diagnostic tests were compared to rLci5 ELISA, which presented earlier infection diagnosis and a greater persistence of positive test results. Accordingly, the use of the rLci5 ELISA can improve CVL diagnostic performance by detecting infected dogs sooner than other testing methods, with enhanced persistence of positive results over the course of the infection.