A stronger antibody response in increased disease severity of SARS-CoV-2.

BACKGROUND: An assessment of the factors that interfere with serum levels and the persistence of anti-SARs-CoV-2 IgG antibodies is essential in order to estimate the risk of reinfection and to plan vaccination. We analyzed the impact of the severity of coronavirus disease 2019 (COVID-19) and the clinical and biological factors regarding the persistence of SARs-CoV-2 anti-spike protein (IgG-S) antibodies at 12 months. METHODS: This was an observational, longitudinal study with individuals who had recovered from COVID-19 between August 2020 and June 2021. Peripheral blood samples were collected from volunteers who were hospitalized (SERIOUS COVID-19) and those who required no hospitalization (COVID-19 LIGHT). Samples were grouped according to days after symptom onset: up to 90, between 91 and 180, ≥ 180 days after symptom onset. A semiquantitative test for IgG anti-spike protein S1(IgG-S1) was used. RESULTS: We analyzed 238 individuals who had recovered from COVID-19, of whom 87 had been hospitalized and 151 had not. They provided 148 and 220 samples, respectively. Among those hospitalized, males (65.5%), volunteers aged over 60 years (41.1%), comorbidities such as arterial hypertension (67.8%) and diabetes mellitus (37.9%) were most frequent. We observed higher median serum IgG-S1 titers among those who had recovered from COVID-19 and had been hospitalized, at all collection time intervals (p < 0.001). We observed a weak correlation of increasing age with humoral IgG-S1 response (Spearman correlation = 0.298). There was a greater probability of IgG-S1 antibody persistence over time among samples from hospitalized individuals compared to samples from non-hospitalized participants (p = 0.001). CONCLUSION: This study has revealed higher titers and a higher probability of the persistence of IgG-S1 in severe cases after SARs-CoV-2 primary infection in unvaccinated recovered patients. Thus, in this study, the severe clinical presentation of COVID-19 was the main factor influencing serum levels and the persistence of IgG-S1 antibodies in COVID-19.

Levels of soluble TNF receptors (sTNFR1 and sTNFR2) increase with clinical worsening of patients and are related to COVID-19 mortality.

The present study aimed to inspect the serum levels of the soluble receptors, sTNFR1 and sTNFR2, in patients with COVID-19. The large production of inflammatory cytokines is an essential process in the pathogenesis of COVID-19. TNF is a multifaceted proinflammatory cytokine which has soluble and membrane receptors. Thus, knowing the role of these receptors will help better understand this disease's immunopathogenesis. We included 131 patients confirmed for SARS-CoV-2, separated into three groups: ward patients without O2 support, group A (n = 14); ward patients with O2 support, group B (n = 85), and patients in an intensive care unit (ICU), group C (n = 32), making up the receptors dosed by flow cytometry. The results showed that sTNFR1 and sTNFR2 are associated with disease severity, being higher in group C when compared to group A. As for the levels of receptors and their relationship with the degree of lung involvement, we found higher values of sTNFR1 in patients in group 1 (pulmonary involvement < 25%), suggesting that inflammatory processes related to TNF are not necessarily associated with the primary site of infection. When we analysed the patients who passed away compared to those who recovered, both receptors significantly increased the mortality numbers. These findings suggest a relevant influence of soluble receptors in the inflammatory processes involved in the pathogenesis of COVID-19. Wherefore, we suggest using these receptors as biomarkers of severity and mortality of the disease.

Inspiratory muscle training in addition to whole body vibration for functional and physical outcomes in pre-frail older women: a randomized controlled trial.

BACKGROUND: to investigate the efficacy of addition of inspiratory muscle training (IMT) to the whole body vibration (WBV) on functional outcomes, physical performance, muscle strength and metabolism in pre-frail older women. METHODS: this study was a randomized double-blind trial. Forty-two older women aged 60-80 years who meet the Cardiovascular Health Study frailty criteria for pre-frailty were randomly allocated to IMT + WBV, IMTsham + WBV or Sham groups. IMT + WBV group received 12 weeks of both trainings, whereas IMTsham + WVB received 12 weeks of WBV alone. Sham group received 12 weeks of IMT with a low fixed load and were positioned at the vibratory platform without therapeutic effect. Participants were evaluated before and after the intervention for the following outcomes: 6-min walk test distance (6MWD), balance using Tinetti test, functional mobility using timed up and go test (TUG), handgrip strength (HGS) and peripheral muscle metabolism (glucose and lactate levels). RESULTS: after the training, both groups IMT + WBV and IMTsham + WBV improved 6MWD [mean percentage changes = 20.31 (SD = 14.62) and 13.02 (SD = 12.14), respectively] compared with Sham [0.27 (SD = 6.51)], P <0.01. There was also a significant decrease of mean percentage changes on time of the TUG for IMT + WBV [-21.87 (SD = 7.87)] and IMTsham + WBV [-11.15 (SD = 13.64)] compared with Sham [-4.25 (SD = 13.25)], P <0.01. IMT + WBV group improved balance when compared with IMTsham + WBV and Sham groups (P <0.05 and < 0.01, respectively). HGS and levels of lactate and glucose were similar between groups. CONCLUSIONS: the addition of IMT to the WBV was effective to improve functionality, balance and physical performance in pre-frail older women.

Expression of co-stimulatory molecules CD80 and CD86 is altered in CD14 + HLA-DR + monocytes from patients with Chagas disease following induction by Trypanosoma cruzi recombinant antigens.

INTRODUCTION: The relationships between monocytes and lymphocytes through MHC class II molecules and costimulatory, are of utmost importance for the production of an efficient immune response. In this work, we assessed the expression of surface molecules CD80 and CD86 on CD14+HLA-DR+ monocytes from patients with Chagas disease. METHODS:: The study population consisted of 31 patients with chronic clinical forms of Chagas disease. Patient blood samples were cultured in the presence of recombinant cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA). RESULTS:: We found considerable differences in the expression profile of surface molecules involved in antigen presentation. CONCLUSIONS:: CRA and FRA may contribute to host immune response evasion by Trypanozoma cruzi.