Serum Vitamin D Levels and Life-Threatening Respiratory Syncytial Virus Infection in Previously Healthy Infants.

BACKGROUND: 25-hydroxyvitamin D (VD) effects on lung function and immune-modulation might affect respiratory syncytial virus (RSV) infection outcomes. We aimed to assess VD levels on admission and their association with life-threatening RSV disease (LTD). METHODS: A prospective cohort study was conducted during 2017-2019. Previously healthy infants aged <12 months, hospitalized with a first episode of RSV infection, were enrolled. LTD was defined by need for intensive care and ventilatory support. Serum VD levels <20 ng/mL were categorized as deficient, and 20-29.9 ng/mL as insufficient. RESULTS: Of 125 patients studied, 73 (58%) were male. Median age was 4 months. Twenty-two patients developed LTD. No differences in viral load were seen between cases with LTD and controls (P = .94). Patients who developed LTD had significantly lower VD levels: median 18.4 ng/mL (IQR, 15.1-26.9 ng/mL) versus 31.7 ng/mL (IQR, 23.6-42.0 ng/mL), P < .001; 59% of infants with LTD had VD deficiency compared with 12% in those with better outcome. Multivariable regression analysis confirmed VD deficiency as a risk factor (odds ratio, 11.83; 95% confidence interval, 3.89-35.9; P < .001). CONCLUSIONS: These findings provide additional evidence for the development of strategies to prevent severe RSV infections.

Interleukin 10 Polymorphisms as Risk Factors for Progression to Chagas Disease Cardiomyopathy: A Case-Control Study and Meta-Analysis.

Background: Chagas disease is a lifelong infection caused by the protozoa Trypanosoma cruzi endemic in Latin-America and emergent worldwide. Decades after primary infection, 20-30% of infected people develop chronic Chagas cardiomyopathy (CCC) while the others remain asymptomatic. CCC pathogenesis is complex but associated with sustained pro-inflammatory response leading to tissue damage. Hence, levels of IL-10 could have a determinant role in CCC etiology. Studies with Latin-American populations have addressed the association of genetic variants of IL-10 and the risk of developing CCC with inconsistent results. We carried out a case control study to explore the association between IL-10-1082G>A (rs18008969), -819C>T (rs1800871), -592A>C (rs1800872) polymorphisms and CCC in a population attending a hospital in Buenos Aires Argentina. Next, a systematic review of the literature and a meta-analysis were conducted combining present and previous studies to further study this association. Methods: Our case control study included 122 individuals with chronic T. cruzi infection including 64 patients with any degree of CCC and 58 asymptomatic individuals. Genotyping of IL-10 -1082G>A, -819C>T, -592A>C polymorphisms was performed by capillary sequencing of the region spanning the three polymorphic sites and univariate and multivariate statistical analysis was undertaken. Databases in English, Spanish and Portuguese language were searched for papers related to these polymorphisms and Chagas disease up to December 2021. A metanalysis of the selected literature and our study was performed based on the random effect model. Results: In our cohort, we found a significant association between TT genotype of -819 rs1800871 and AA genotype of -592 rs1800872 with CCC under the codominant (OR=5.00; 95%CI=1.12-23.87 P=0,04) and the recessive models (OR=5.37; 95%CI=1.12-25.68; P=0,03). Of the genotypes conformed by the three polymorphic positions, the homozygous genotype ATA was significantly associated with increased risk of CCC. The results of the meta-analysis of 754 cases and 385 controls showed that the TT genotype of -819C>T was associated with increased CCC risk according to the dominant model (OR=1.13; 95% CI=1.02-1.25; P=0,03). Conclusion: The genotype TT at -819 rs1800871 contributes to the genetic susceptibility to CCC making this polymorphism a suitable candidate to be included in a panel of predictive biomarkers of disease progression.

Distinct Immune Phenotypes and Cytokine Profiles in Children with Differing Severity of COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is usually mild and self-limited in children. However, a few Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infections in children may progress to severe disease with respiratory distress or can result in a multisystem inflammatory syndrome (MIS-C) associated with COVID-19. The immune mechanisms for these differential clinical outcomes are largely unknown. METHODS: A prospective cohort study was performed to analyze the laboratory parameters, antibody response, immune phenotypes and cytokine profiles of 51 children with different clinical presentations of COVID-19. RESULTS: We found that the absolute lymphocyte counts gradually decreased with disease severity. Furthermore, SARS-CoV-2 IgG levels in the acute phase and convalescence were not significantly different in patients with different disease severity. A decrease in CD3 + , CD4 + and CD8 + T cells was observed as disease severity increased. Both CD4 + and CD8 + T cells were activated in children with COVID-19, but no difference in the percentage of HLADR + -expressing cells was detected across the severity groups. In contrast, MIS-C patients exhibited augmented exhausted effector memory CD8 + T cells. Interestingly, the cytokine profile in sera of moderate/severe and MIS-C patients revealed an increase in anti-inflammatory IL-1RA and a suppression of tumor necrosis factor-α, RANTES, eotaxin and PDGF-BB. MIS-C patients also exhibited augmented IL-1ß. CONCLUSIONS: We report distinct immune profiles dependent on severity in pediatric COVID-19 patients. Further investigation in a larger population will help unravel the immune mechanisms underlying pediatric COVID-19.

Genetic Susceptibility to Life-threatening Respiratory Syncytial Virus Infection in Previously Healthy Infants.

BACKGROUND: Genetic background may be an important host determinant of respiratory syncytial virus (RSV) disease severity, but full characterization of susceptibility genes remains unclear. This study aimed to assess the presence of specific single-nucleotide polymorphisms (SNPs) in selected genes codifying for different components of the antiviral innate immune response, to determine their role for developing RSV life-threatening disease (LTD). METHODS: Prospective cohort study including previously healthy full-term infants hospitalized with a first RSV infection during 2017-2018. RSV detection, quantification and subgroup determination, and genotyping for SNPs in Toll-like receptor 4 (TLR4 rs4986790, rs4986791), Toll-like receptor 8 (TLR8 rs3761624), macrophage receptor with collagenous structure(MARCO rs1318645) and myxovirus resistance 1(MX1 rs469390) were performed by real-time polymerase chain reaction in nasopharyngeal aspirates obtained on admission. Patients with LTD were those admitted to the intensive care unit requiring ventilatory support. RESULTS: Seventy-five patients were studied, 15 (20%) developed LTD. Infants with concurrent SNPs in MX1 and TLR8, MARCO and TLR8 or MARCO, MX1 and TLR8 had an increased risk of developing LTD. Multivariable logistic regression analysis confirmed this significant association (odds ratio [OR] = 3.75, P = 0.046; OR = 3.92, P = 0.040; OR = 5.56, P = 0.010, respectively). No differences were seen in viral load of patients with LTD compared with those with better outcome (P = 0.737). In addition, no differences in viral load were seen in patients with the described high-risk SNPs compared with those without these polymorphisms. CONCLUSIONS: Life-threatening RSV infection in previously healthy infants was significantly associated with the presence of combined SNPs in MARCO, MX1 and TLR8.