Purpose There is still scarce data on SARS-CoV-2 infection in patients with Inborn Errors of Immunity (IEI) and many unresolved questions. We aimed to describe the clinical outcome of SARS-CoV-2 infection in Brazilian IEI patients and identify factors influencing the infection. Methods We did a cross-sectional, multicenter study that included patients of any age affected by IEI and SARS-CoV-2 infection. The variables studied were sex, age, type of IEI, comorbidities (number and type), treatment in use for IEI, clinical manifestations and severity of SARS-CoV-2 infection. Results 121 patients were included: 55.4% female, ages from six months to 74 yo (median age = 25.1 yo). Most patients had predominantly antibody deficiency (n = 53). The infection was mostly asymptomatic (n = 21) and mild (n = 66), and one child had multisystem inflammatory syndrome (MIS-C). We could not observe sex-related susceptibility, and there was a weak correlation between age and severity of infection. The number of comorbidities was higher in severe cases, particularly bronchiectasis and cardiopathy. There were no severe cases in hereditary angioedema patients. Six patients aged 2 to 74 years died, three of them with antibody deficiency. Conclusion The outcome was mild in most patients, but the Case Fatality Ratio was higher than in the general population. However, the type of IEI was not a determining factor for severity, except for complement deficiencies linked to milder COVID-19. The severity of SARS-CoV-2 infection seems to be more related to older age, a higher number of comorbidities and type of comorbidities (bronchiectasis and cardiopathy).

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Objective To evaluate the secondary attack rate (SAR) in children and adolescents, contacts of essential activities workers who were infected by SARS‐CoV‐2; and to describe associated clinical and epidemiological data. Methods A cross‐sectional study conducted in children and adolescents aged 5 to 19 years of age, that were household contacts of parents and other relatives who were infected by SARS‐CoV‐2 in the city of Goiânia, Central Brazil, from March to October 2020. Sociodemographic and clinical data were collected from all participants. Nasopharyngeal and oropharyngeal swabs were collected and tested for SARS‐CoV‐2 RNA using real‐time reverse transcription polymerase chain reaction (RT‐PCR). Factors associated with SARS‐CoV‐2 infection and SAR were analyzed using Poisson regression. Results A total of 267 children and adolescents were investigated. The prevalence of SARS‐CoV‐2 RNA by the real‐time RT‐PCR test and/or the presence of COVID‐19 associated symptoms (anosmia/ageusia and flu syndrome) was 25.1% (95.0% Confidence Interval [95.0% CI] = 20.3‐30.6). More than half (55.1%) of the participants had sygns and symptoms. The most prevalent signs and symptoms in positive individuals were nasal congestion (62.7%), headache (55.2%), cough (50.8%), myalgia (47.8%), runny nose (47.8%), and anosmia (47.8%). The Poisson model showed that the following signs or symptoms were associated with SARS‐CoV‐2 infection: fever, nasal congestion, decreased appetite, nausea, anosmia, and ageusia. Families that had more than one infected adult, in addition to the index case, presented greater transmissibility to children and adolescents. Conclusions Our results contribute to the hypothesis that children and adolescents are not important sources of transmission of SARS‐CoV‐2 in the home environment during a period of social distancing and school closure; even though they are susceptible to infection in the household (around ¼ of our study population).

These findings revealed a disturbed B-cell homeostasis with unconventional maturation of B lymphocyte memory cells, which can explain the consequent impairment of humoral immunity.

We aim to evaluate the proportion of transitional immature and CD21low B cells in patients with Ataxia-telangiectasia (AT), a complex disease with humoral and cellular immune dysfunction. Methods Blood samples were obtained from 18 AT patients and 15 age-sex-matched controls (C). This study was approved by the Medical Ethic Committee of the Federal University of Sao Paulo. Total numbers of T, B, and NK cells were enumerated from whole blood samples using TruCount Tubes. Peripheral blood mononuclear cells (PBMC) were cryopreserved, thawed and stained with conjugated monoclonal antibodies: anti-CD19-PerCP anti-CD3-APCCy7, anti-CD24-PE, anti-CD21-APC, anti-CD38-PECy7. Five-color flow cytometric immunophenotyping was performed on a BD LSRFortessa (BD Biosciences), and data were analyzed with FlowJo software (TreeStar, Stanford University, CA). Transitional B cells were characterized as CD3-CD19 + CD24 hi CD38 hi , and CD21low B cells as CD3-CD19 + CD21 lo CD38 lo. Statistical analysis was performed with SPSS 20.0 and STATA 12, and a significance threshold of <0.05 was used.