ABSTRACT Background: São Paulo city has been one of the regions most affected by the COVID-19 pandemic in Brazil. Frequent asymptomatic and oligosymptomatic infections and poor access to diagnostic tests make serosurveys crucial to monitor the magnitude of the epidemic and to inform public health policies, such as vaccination plans. Objectives: To estimate, early in the epidemic, the seroprevalence of antibodies to SARS-CoV-2 in adults living in the six most affected districts in São Paulo city, and to assess potential associated risk factors. Methods: This was a cross-sectional population-based survey of 1,152 households randomly selected from 72 census tracts. During the period May 4-12, 2020, 463 participants completed a questionnaire on sociodemographic characteristics and history of symptoms in the past two weeks, and provided a blood sample. Prevalence of SARS-CoV-2 antibodies was the outcome of interest and was estimated based on results of two immunoassays, Maglumi SARS-CoV-2 chemiluminescence assay Immunoglobulin (Ig) M (IgM) and IgG, and Roche electrochemiluminescence assay total Ig. Serum samples reactive to either assay were considered positive. Results: Weighted overall seroprevalence was 6% (95%CI 3.9-8.3%). No association was observed between seropositivity and sex, age group or education level. Participants who reported black and brown skin color showed a 2.7 fold higher prevalence than people with white skin (p = 0.007). Among the 30 seropositive individuals, 14 (46.6%) reported no COVID-19 compatible symptoms in the past two weeks. Conclusion: This study represents the first assessment of SARS-CoV-2 seroprevalence in the city of São Paulo and 6% is the baseline estimate of a series of population-based seroprevalence surveys. Serological screening using sound serological assays is the key tool to monitoring temporal and geographic changes in the spread of the virus through an important epicenter of the COVID-19 pandemic in Brazil. Ultimately, it may inform prevention and control efforts.

CONTEXTO E OBJETIVO O termo mastocitose abrange um grupo de raras doenças caracterizado por proliferação neoplásica e acúmulo de mastócitos clonais em um ou mais órgãos. O objetivo do presente estudo foi avaliar os principais elementos para o diagnóstico e tratamento dessas desordens. TIPO DE ESTUDO E LOCAL Revisão narrativa da literatura realizada no Grupo Fleury, São Paulo, Brasil. MÉTODOS O presente estudo revisou artigos científicos publicados nas bases de dados PubMed, Embase (Excerpta Medica Database), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) e Cochrane Library, que foram identificados com o termo de busca “mastocitose”. RESULTADOS A apresentação clínica da mastocitose é marcadamente heterogênea, variando de lesões cutâneas que podem regredir espontaneamente, até formas agressivas associadas a falência de órgãos e curta sobrevida. Atualmente, sete subtipos de mastocitose são reconhecidos pela classificação de tumores hematopoéticos da Organização Mundial de Saúde; o diagnóstico é realizado com base nas manifestações clínicas e na identificação de mastócitos neoplásicos por métodos morfológicos, imunofenotípicos, genéticos e moleculares. Mastócitos anômalos apresentam morfologia atípica, frequentemente fusiforme, e expressão aberrante dos antígenos CD25 e CD2. Aumento de triptase sérica é um achado comum em alguns subtipos; e mais que 90% dos pacientes apresentam mastócitos com a mutação KIT D816V. CONCLUSÃO No presente artigo, descrevemos os sintomas e sinais mais comuns em pacientes com mastocitose e sugerimos uma prática abordagem para o diagnóstico, classificação e tratamento clínico inicial.

CONTEXT AND OBJECTIVE The term mastocytosis covers a group of rare disorders characterized by neoplastic proliferation and accumulation of clonal mast cells in one or more organs. The aim of this study was to assess the principal elements for diagnosing and treating these disorders. DESIGN AND SETTING Narrative review of the literature conducted at Grupo Fleury, São Paulo, Brazil. METHODS This study reviewed the scientific papers published in the PubMed, Embase (Excerpta Medica Database), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) and Cochrane Library databases that were identified using the search term “mastocytosis.” RESULTS The clinical presentation of mastocytosis is remarkably heterogeneous and ranges from skin lesions that may regress spontaneously to aggressive forms associated with organ failure and short survival. Currently, seven subtypes of mastocytosis are recognized through the World Health Organization classification system for hematopoietic tumors. These disorders are diagnosed based on clinical manifestations and on identification of neoplastic mast cells using morphological, immunophenotypic, genetic and molecular methods. Abnormal mast cells display atypical and frequently spindle-shaped morphology, and aberrant expression of the CD25 and CD2 antigens. Elevation of serum tryptase is a common finding in some subtypes, and more than 90% of the patients present the D816V KIT mutation in mast cells. CONCLUSION Here, we described the most common signs and symptoms among patients with mastocytosis and suggested a practical approach for the diagnosis, classification and initial clinical treatment of mastocytosis.