Seroprevalence of IgG and IgM anti-SARS-CoV-2 among voluntary blood donors in Rio de Janeiro, Brazil

Background: In Brazil, mathematical models for derivingestimates and projections of COVID-19 cases have been developed without data on asymptomatic SARS-CoV-2 infection. We estimated the seroprevalence of antibodies to SARS-CoV-2 among blood donors in the State of Rio de Janeiro. Methods: Data were collected on 2,857 blood donors from April 14 to 27, 2020. We report the crude prevalence of antibodies to SARS-CoV-2, the weighted prevalence by the total state population, and adjusted prevalence estimates for test sensitivity and specificity. To establish the correlates of SARS-CoV-2 prevalence, we used logistic regression models. The analysis included period and site of blood collection, sociodemographic characteristics, and place of residence. Results: The proportion of SARS-Cov-2 positive tests without any adjustment was 4.0% (95% CI 3.3-4.7%), and the weighted prevalence was 3.8% (95% CI 3.1-4.5%). Further adjustment by test sensitivity and specificity produced lower estimates, 3.6% (95% CI 2.7-4.4%) and 3.3% (95% CI 2.6-4.1%), respectively. The variable most significantly associated with the crude prevalence was the period of blood collection: the later the period, the higher the prevalence. Regarding socio-demographic characteristics, the younger the blood donors, the higher the prevalence, and the lower the educational level, the higher the odds of a positive SARS-Cov-2 antibody. Similar results were found for the weighted prevalence. Discussion: Although our findings resulted from a convenience sample, they match some basic premises: the increasing trend over time, since the epidemic curve in the state is still on the rise; the higher prevalence among the youngest who are more likely to circulate; and the higher prevalence among the less educated as they have more difficulties in following the social distancing recommendations. Despite the study limitations, it is possible to infer that protective levels of natural herd immunity to SARS-CoV-2 are far from being reached in Rio de Janeiro. (AU)

Seroprevalence of anti-SARS-CoV-2 among blood donors in Rio de Janeiro, Brazil

ABSTRACT OBJECTIVE To estimate the seroprevalence of antibodies to SARS-CoV-2 among blood donors in the state of Rio de Janeiro, Brazil. METHODS Data were collected on 2,857 blood donors from April 14 to 27, 2020. This study reports crude prevalence of antibodies to SARS-CoV-2, population weighted prevalence for the state, and prevalence adjusted for test sensitivity and specificity. Logistic regression models were used to establish the correlates of SARS-CoV-2 prevalence. For the analysis, we considered collection period and site, sociodemographic characteristics, and place of residence. RESULTS The proportion of positive tests for SARS-Cov-2, without any adjustment, was 4.0% (95%CI 3.3-4.7%), and the weighted prevalence was 3.8% (95%CI 3.1-4.5%). We found lower estimates after adjusting for test sensitivity and specificity: 3.6% (95%CI 2.7-4.4%) for the non-weighted prevalence, and 3.3% (95%CI 2.6-4.1%) for the weighted prevalence. Collection period was the variable most significantly associated with crude prevalence: the later the period, the higher the prevalence. Regarding sociodemographic characteristics, the younger the blood donor, the higher the prevalence, and the lower the education level, the higher the odds of testing positive for SARS-Cov-2 antibody. We found similar results for weighted prevalence. CONCLUSIONS Our findings comply with some basic premises: the increasing trend over time, as the epidemic curve in the state is still on the rise; and the higher prevalence among both the youngest, for moving around more than older age groups, and the less educated, for encountering more difficulties in following social distancing recommendations. Despite the study limitations, we may infer that Rio de Janeiro is far from reaching the required levels of herd immunity against SARS-CoV-2.

Anticorpos reativos contra painel em episódios de disfunção do enxerto no transplante renal / Panel reactive antibodies in episodies of kidney allograft dysfunction

O objetivo deste trabalho foi avaliar a correlação entre episódios de disfunção do enxerto e a presença de anticorpos anti-HLA classe 1 em pacientes transplantados renais pelas metodologias de citotoxicidade dependente de complemento (CDC), CDC sensibilizado por antiglobulina humana (AGH) e ELISA. Métodos :Foram estudados 30 pacientes consecutivos transplantados renais no Serviço de Nefrologia do Hospital Universitário Pedro Ernesto da UERJ, no período de dezembro de 1998 a outubro de 1999. Dezenove pacientes deste grupo apresentaram 27 episódios de disfunção do enxerto, diagnosticados pela presença dos critérios clássicos (febre, dor no enxerto, oligúria, ganho de peso) e rápido aumento na creatinina sérica. O diagnóstico de rejeição aguda foi confirmado em quatro casos submetidos à biápsia renal, de acordo com a classificação de Banff Foram avaliadas 322 amostras semanais de soro, pré e pós-transplante, por CDC e CDC com AGH e 298 delas por ELISA. A análise do tempo decorrido até o episódio de disfunção do enxerto, em função do percentual do PRA das amostras, foi realizada através do teste da Regressão de Cox e teste do Qui-quadrado. Resultados :A detecção de anticorpos anti-HLA classe 1, pelo método de CDC com AGH, apresentou correlação estatisticamente significativa com os episódios de disfunção do enxerto, com razão de risco acumulado = 10,06 e p=0,006. Conclusão :Os dados sugerem que a pesquisa de PRA pode ser um dos métodos utilizados para o monitorização de episódios de disfunção do enxerto.

Systemic lupus erythematosus associated with papulonodular mucinosis

Introduçäo: Mucinose lúpica é uma manifestaçäo rara caracterizada pela presença difusa de mucina na derme sem as alteraçöes epidérmicas ou inflamatórias encontradas nas formas mais convencionais de dermatites do lúpus eritematoso sistêmico (LES). Recentemente, uma associaçäo de LES com o alelo de HLA-DR15 foi enfatizada na populaçäo brasileira. O objetivo do presente estudo foi avaliar o perfil imunogenético e de auto-anticorpos de três irmäs, uma com LES, uma com mucinose papular e uma assintomática. Resultados: A primeira irmä tinha fator antinuclear (FAN) e anticorpos contra as proteínas Ro, SS-A/Ro, SS-B/La e P ribossomais positivos. A segunda tinha FAN positivo e desenvolveu sintomas compatíveis com LES, embora näo preenchesse os critérios para este diagnóstico. Ambas compartilhavam o alelo HLA-DR15. A irmä assintomática näo apresentava auto-anticorpos nem o alelo HLA-DR15. Conclusöes: Mucinose papular, uma rara manifestaçäo de LES, pode aparecer antes de qualquer outro sinal de LES em um indivíduo geneticamente suscetível (HLA-DR15+), levando à investigaçäo deste diagnóstico