Analysis of serum immunoglobulin level in children with Burkitt lymphoma / 中华儿科杂志

Objective: To summarize changes of serum immunoglobulin levels before and after chemotherapy in children with Burkitt lymphoma (BL), so as to investigate the effects of chemotherapy and rituximab on serum immunoglobulin levels in children with BL. Methods: Clinical data of 223 children with newly diagnosed Burkitt lymphoma at Beijing Children's Hospital from January 2009 to April 2017 were analyzed retrospectively. They were treated according to the modified LMB 89 regimen and some of them received combined rituximab therapy during the chemotherapy. The serum immunoglobulin (IgA, IgM, IgG) before chemotherapy, at the time of discontinuing chemotherapy, as well as 6, 12, 24, 36 months after chemotherapy were collected. Changes of serum IgA, IgM and IgG with time among different treatment groups were compared using repeated measures ANOVA. Results: According to risk group, 223 children were devided into group B（n=53）and group C（n=170）. Before chemotherapy, 109 cases (48.9%) were combined with hypogammaglobulinemia. The serum IgA, IgM, and IgG levels of all the patients were (0.9±0.7), 1.2 (0.5, 1.3) and (7.2±2.9) g/L before chemotherapy, (0.5±0.4), 0.2 (0.1, 0.3) and (6.3±2.3) g/L at the time of discontinuing chemotherapy (t=13.63, Z=-11.99, t=4.57, all P<0.05). There were statistical difference in IgA, IgM levels of group B and IgA, IgM, IgG levels of group C before chemotherapy and at the time of discontinuing chemotherapy (t=8.86, Z=-6.28, t=11.19, Z=-10.15, t=4.50, all P<0.05). The differences of serum IgA and IgG levels at the time after chemotherapy among patients treated with chemotherapy alone and those treated with chemotherapy combined rituximab in group B and C were significant (F=5.38, P=0.002 and F=4.22, P=0.007). Conclusions: Approximately half of children with BL have already existed hypogammaglobulinemia at initial diagnosis prior to the start of treatment. The modified LMB 89 regimen have significant effect on humoral immunity of children with BL. In the process of immune reconstruction after chemotherapy, rituximab has more significant effect on serum IgA and IgG levels in BL patients.

Comparison between Enzyme Immunoassays Performed on Samples of Dried Blood and Serum for Toxoplasmosis Prenatal Screening: Population-based Study / Comparação entre ensaios imunoenzimáticos realizados em amostras de sangue seco e soro para triagem prénatal da toxoplasmose: Estudo populacional

Abstract Objective Most prenatal screening programs for toxoplasmosis use immunoassays in serum samples of pregnant women. Few studies assess the accuracy of screening tests in dried blood spots, which are of easy collection, storage, and transportation. The goals of the present study are to determine the performance and evaluate the agreement between an immunoassay of dried blood spots and a reference test in the serum of pregnant women from a population-based prenatal screening program for toxoplasmosis in Brazil. Methods A cross-sectional study was performed to compare the immunoassays Imunoscreen Toxoplasmose IgM and Imunoscreen Toxoplasmose IgG (Mbiolog Diagnósticos, Ltda., Contagem, Minas Gerais, Brazil)in dried blood spots with the enzymelinked fluorescent assay (ELFA, BioMérieux S.A., Lyon, France) reference standard in the serum of pregnant women from Minas Gerais Congenital Toxoplasmosis Control Program. Results The dried blood spot test was able to discriminate positive and negative results of pregnant women when comparedwith the reference test, with an accuracy of 98.2% for immunoglobulin G (IgG), and of 95.8% for immunoglobulin M (IgM). Conclusion Dried blood samples are easy to collect, store, and transport, and they have a good performance,making this a promisingmethod for prenatal toxoplasmosis screening programs in countries with continental dimensions, limited resources, and a high prevalence of toxoplasmosis, as is the case of Brazil.

Resumo Objetivo A maioria dos programas de triagem pré-natal para toxoplasmose utiliza imunoensaios em amostras de soro de gestantes. Poucos estudos avaliam a acurácia dos testes de triagem em amostras de sangue seco, que são de fácil coleta, armazenamento e transporte. Este estudo teve como objetivo determinar o desempenho e avaliar a concordância entre um imunoensaio em sangue seco e um teste de referência em soro de gestantes de um programa de rastreamento pré-natal de base populacional para toxoplasmose no Brasil. Métodos Realizou-se um estudo transversal para comparar os imunoensaios Imunoscreen Toxoplasmose IgM e Imunoscreen Toxoplasmose IgG (Mbiolog Diagnósticos, Ltda., Contagem, Minas Gerais, Brazil) em sangue seco com o padrão de referência ensaio fluorescente ligado a enzimas (enzyme-linked fluorescent assay, ELFA, BioMérieux S.A., Lion, França) no soro de gestantes do Programa de Controle de Toxoplasmose Congênita de Minas Gerais. Resultados O exame em sangue seco foi capaz de discriminar os resultados positivos e negativos das gestantes quando comparado ao teste de referência, com acurácia de 98,2% para imunoglobulina G (IgG), e de 95,8% para imunoglobulina M (IgM). Conclusão O sangue seco apresenta bom desempenho e é uma amostra de fácil coleta, armazenamento e transporte, o que o torna um método promissor para programas de triagem pré-natal de toxoplasmose em países com dimensões continentais, recursos limitados, e alta prevalência de toxoplasmose, como é o caso do Brasil.

Significación de los marcadores infecciosos para identificar portadores de hepatitis B en donantes de sangre / Significance of hepatitis B surface antigen, IgM/IgG core antibody and hepatitis B virus DNA in blood donors

Resumen Introducción: La identificación de portadores del virus de la hepatitis B en donantes de sangre es imperativo para evitar la transmisión de la enfermedad a través de transfusiones sanguíneas. Objetivo: Determinar si los donantes de sangre con resultados positivos de los marcadores serológicos HbsAg y anti-HBc eran portadores de ADN del virus de la hepatitis B. Métodos: Se recolectaron 12 745 muestras de seis bancos de sangre ecuatorianos, las cuales fueron analizadas con pruebas serológicas para identificar los marcadores infecciosos HBsAg, anti-HBc, anti-HBs mediante prueba ELISA automatizada. Todas las muestras positivas para uno, dos o los tres marcadores fueron analizadas con técnica molecular para determinar la presencia de ADN viral. Resultados: Se identificó que 27.5 % de las muestras reactivas solo a anti-HBc y 100 % de las muestras con resultados positivos de HBsAg/anti-HBc-IgM/IgG presentaron ADN del virus de la hepatitis B (p = 0.001). Conclusiones: La elección de los marcadores de infección y los métodos de detección definen los resultados. Es importante la realización de dos pruebas serológicas y una molecular para identificar a los portadores del virus de la hepatitis B y evitar su transmisión.

Abstract Introduction: Identification of hepatitis B virus carriers in blood donors is imperative in order to avoid transmission of the disease via blood transfusion. Objective: To determine if blood donors with positive results for serological markers HBsAg and anti-HBc were hepatitis B virus DNA carriers. Methods: 12,745 samples were collected from six Ecuadorian blood banks and analyzed for HBsAg, anti-HBc and anti-HBs infectious markers by automated ELISA. All samples that tested positive for one, two or all three markers were analyzed with molecular techniques to determine the presence of viral DNA. Results: 27.5 % of the samples that were reactive for anti-HBc alone and 100 % of those with positive results for HbsAg and IgM/IgG anti-HBc were identified to contain hepatitis B virus DNA (p = 0.001). Conclusions: The selection of infection markers, as well as the detection methods define the results. Performing two serological and one molecular test is important in order to identify hepatitis B virus carriers and prevent its transmission.

Seroprevalence of IgM and IgG Antibodies against SARS-CoV-2 in Asymptomatic People in Wuhan: Data from a General Hospital Near South China Seafood Wholesale Market during March to April in 2020 / 生物医学与环境科学（英文）

The aim of this study was to estimate the seroprevalence of immunoglobulin M (IgM) and G (IgG) antibodies against SARS-CoV-2 in asymptomatic people in Wuhan. This was a cross-sectional study, which enrolled 18,712 asymptomatic participants from 154 work units in Wuhan. Pearson Chi-square test,

Seroprevalence of anti-SARS-CoV-2 IgG in asymptomatic and pauci-symptomatic people over a 5 month survey in Argentina / Seroprevalencia de anticuerpos IgG contra el SARS-CoV-2 en personas asintomáticas y paucisintomáticas en un estudio de 5 meses en Argentina / Soroprevalência de IgG contra SARS-CoV-2 em indivíduos assintomáticos e paucissintomáticos em um inquérito de 5 meses na Argentina

ABSTRACT Objective. To evaluate the seroprevalence of COVID-19 infection in pauci-symptomatic and asymptomatic people, the associated epidemiological factors, and IgG antibody kinetic over a 5-month period to get a better knowledge of the disease transmissibility and the rate of susceptible persons that might be infected. Methods. Seroprevalence was evaluated by a cross-sectional study based on the general population of Santa Fe, Argentina (non-probabilistic sample) carried out between July and November 2020. A subgroup of 20 seropositive individuals was followed-up to analyze IgG persistence. For the IgG anti-SARS-CoV-2 antibodies detection, the COVID-AR IgG® ELISA kit was used. Results. 3 000 individuals were included conforming asymptomatic and pauci-symptomatic groups (n=1 500 each). From the total sample, only 8.83% (n=265) presented reactivity for IgG anti-SARS-CoV-2. A significant association was observed between positive anti-SARS-CoV-2 IgG and a history of contact with a confirmed case; the transmission rate within households was approximately 30%. In the pauci-symptomatic group, among the seropositive ones, anosmia and fever presented an OR of 16.8 (95% CI 9.5-29.8) and 2.7 (95% CI 1.6-4.6), respectively (p <0.001). In asymptomatic patients, IgG levels were lower compared to pauci-symptomatic patients, tending to decline after 4 months since the symptoms onset. Conclusion. We observed a low seroprevalence, suggestive of a large population susceptible to the infection. Anosmia and fever were independent significant predictors for seropositivity. Asymptomatic patients showed lower levels of antibodies during the 5-month follow-up. IgG antibodies tended to decrease over the end of this period regardless of symptoms.

RESUMEN Objetivo. Evaluar la seroprevalencia de la infección por el virus causante de la COVID-19 en personas paucisintomáticas y asintomáticas, los factores epidemiológicos asociados y la cinética de los anticuerpos IgG durante un período de cinco meses para conocer mejor la transmisibilidad de la enfermedad y la tasa de personas susceptibles a estar infectadas. Métodos. Se evaluó la seroprevalencia mediante un estudio transversal basado en la población general de Santa Fe, Argentina (muestra no probabilística) llevado a cabo entre julio y noviembre del 2020. Se realizó un seguimiento de un subgrupo de 20 personas seropositivas para analizar la persistencia de los anticuerpos IgG. Para la detección de los anticuerpos IgG contra SARS-COV-2, se empleó el kit ELISA COVID-AR IgG®. Resultados. Hubo 3 000 participantes divididos en un grupo asintomático y un grupo paucisintomático (n=1 500 cada grupo). De la muestra total, solo 8,83% (n=265) presentó una reactividad de IgG contra el SARS-CoV-2. Se observó una asociación significativa entre anticuerpos IgG positivos contra el SARS-CoV-2 y antecedente de contacto con un caso confirmado. La tasa de transmisión en el hogar fue de 30% aproximadamente. En el grupo paucisintomático, entre las personas seropositivas, la anosmia y la fiebre presentaron un OR de 16,8 (IC 95% 9,5-29,8) y 2,7 (IC 95% 1,6-4,6), respectivamente (p <0,001). En los pacientes asintomáticos, los niveles de IgG fueron inferiores en comparación con los pacientes paucisintomáticos, con tendencia a la baja pasados cuatro meses desde la aparición de los síntomas. Conclusiones. Se observó una seroprevalencia baja, indicadora de una gran población susceptible a la infección. La anosmia y la fiebre fueron factores predictivos independientes de relevancia para la seropositividad. Los pacientes asintomáticos mostraron niveles inferiores de anticuerpos durante el seguimiento de cinco meses. Los anticuerpos IgG tendieron a disminuir hacia el final del período con independencia de los síntomas.

RESUMO Objetivo. Avaliar a soroprevalência de anticorpos contra a COVID-19 em indivíduos paucissintomáticos e assintomáticos, os fatores epidemiológicos associados e a cinética dos anticorpos da classe IgG em um período de 5 meses, visando aprimorar o conhecimento sobre a transmissibilidade da doença e a taxa de suscetíveis à infecção. Métodos. Inquérito transversal de soroprevalência realizado na população geral (amostra não probabilística) de Santa Fé, na Argentina, entre julho e novembro de 2020. Um subgrupo de 20 indivíduos soropositivos foi acompanhado para analisar a persistência de anticorpos IgG. O kit de ensaio imunoenzimático (ELISA) COVID-AR IgG® foi usado para a detecção de anticorpos IgG contra SARS-CoV-2. Resultados. A amostra compreendeu 3 000 indivíduos, divididos entre assintomáticos e paucissintomáticos (n = 1.500 por grupo). Deste total, somente 8,83% (n = 265) apresentaram reatividade, com a detecção de anticorpos IgG contra SARS-CoV-2. Observou-se uma associação significativa entre a presença de anticorpos IgG contra SARS-CoV-2 e histórico de contato com caso confirmado. A taxa de transmissão intradomiciliar foi de aproximadamente 30%. No grupo paucissintomático, entre os soropositivos, o odds ratio (OR) para anosmia foi de 16,8 (IC 95% 9,5-29,8), e para febre, 2,7 (IC 95% 1,6-4,6) (p <0,001). Os indivíduos assintomáticos apresentaram níveis de IgG mais baixos que os paucissintomáticos, com uma tendência de declínio após 4 meses do início dos sintomas. Conclusões. Observou-se uma soroprevalência baixa de anticorpos contra a COVID-19 na população estudada, o que indica um grande número de pessoas suscetíveis à infecção. Anosmia e febre foram preditores importantes independentes de soropositividade. Os assintomáticos apresentaram níveis mais baixos de anticorpos aos 5 meses de acompanhamento. Houve uma tendência de redução dos anticorpos IgG ao final deste período, independentemente da presença de sintomas.

Neonatal infection and passive acquisition of serum total IgG and reactive with Streptococcus B, anti-LPS of Klebsiella spp and Pseudomonas spp antibodies in twins

SUMMARY OBJECTIVE To describe the concentration of total and specific IgG antibodies anti-Streptococcus B, anti-lipopolysaccharide of Klebsiella spp, and anti-lipopolysaccharide of Pseudomonas spp in the umbilical cord of newborn(NB) twins and to analyze the association between neonatal infection and antibody concentration in the umbilical cord blood. METHODS A prospective cross-sectional study of a cohort of NB twins admitted during the period of 20 months. Patients with malformations and mothers with infection were excluded. Variables analyzed: gestational age(GA); birth weight(BW); antibody concentrations in umbilical cord blood; infection episodes. We used the paired Student t-test, Spearman correlation, and generalized estimation equation. RESULTS 57 pairs of twins were included, 4 excluded, making the sample of 110 newborns. GA=36±1.65weeks and BW=2304.8±460g(mean±SD). Antibody concentrations in twins(mean±SD): total IgG=835.71±190.73mg/dL, anti-StreptococcusB IgG=250.66±295.1 AU/mL, anti-lipopolysaccharide of Pseudomonas spp IgG=280.04±498.66 AU/mL and anti-lipopolysaccharide of Klebsiella spp IgG=504.75±933.93 AU/mL. There was a positive correlation between maternal antibody levels and those observed in newborns(p <0.005). The transplacental transfer of maternal total IgG and anti-LPS Pseudomonas IgG antibodies was significantly lower at NB GA <34 weeks(p <0.05). Five newborns were diagnosed with an infection. Infants with infection had significantly lower total IgG concentration(p <0.05). CONCLUSION This study showed a positive correlation between maternal and newborn antibodies levels. In infants younger than 34 weeks there is less transfer of total IgG and anti-LPS Pseudomonas IgG. The highest incidence of infection in the newborn group who had significantly lower total IgG serum antibodies reinforces the importance of anti-infectious protection afforded by passive immunity transferred from the mother.

RESUMO OBJETIVOS Descrever o título de anticorpos IgG total e específico anti-Streptococcus B, anti-lipopolissacarídeos(LPS) de Klebsiella e Pseudomonas no cordão umbilical em gêmeos e analisar a possível associação entre os títulos desses anticorpos e a ocorrência de infecção. MÉTODOS Estudo prospectivo transversal de uma coorte de recém-nascidos (RN) gemelares em 20 meses. Excluídos: malformação, infecção congênita ou materna. Variáveis estudadas: idade gestacional(IG); peso de nascimento(PN); título de anticorpos e episódios de infecção. Foram utilizados testes t-Student pareado, correlação de Spearman e equações de estimação generalizadas. RESULTADOS Elegíveis 59 pares de gêmeos, excluídos 4 e incluídos 55 pares (n=110RN). A IG foi 36±1,65semanas e o PN foi 2304,8±460g (média±DP). Concentrações de anticorpos dos RN(média±DP): IgG total=835,71±190,73 mg/dL, IgG anti-Streptococcus B=295,1±250,66 UA/mL, IgG anti-LPS Pseudomonas=280,04±498,66 UA/mL e IgG anti-LPS Klebsiella=504,75± 933,93UA/mL. Houve correlação positiva entre níveis de anticorpos maternos e aqueles observados nos RN (p<0,005). A transferência transplacentária de anticorpos maternos IgG total e IgG anti-LPS Pseudomonas foi significativamente menor em RN IG < 34semanas (p<0,05). Foram diagnosticados 5 RN com infecção. Os RN que apresentaram infecção tinham concentração de IgG total significativamente menor (p<0,05). CONCLUSÕES Na população estudada existe correlação entre os anticorpos maternos e os níveis de anticorpos no RN. Nos gêmeos menores que 34 semanas há menor transferência de IgG total e IgG anti-LPS Pseudomonas. Nos RN com infecção a concentração de IgG total é significativamente menor, o que demonstra a maior vulnerabilidade e risco de infecção dessa população e a importância da imunidade passiva transferida pela placenta.

Seroprevalence of chikungunya virus infection in five hospitals within Anyigba, Kogi State of Nigeria

ABSTRACT Febrile illnesses in developing countries are often misdiagnosed as malaria or typhoid fever. Although arboviral infections have similar clinical symptoms, they are usually not screened because of limited resources and the fact that there are several viruses in this group. Chikungunya virus (CHIKV) has been isolated in parts of Nigeria, but there is no documented evidence of the infection in Kogi State. This study determined seroprevalence of active and past CHIKV infection among febrile patients who tested negative for malaria and typhoid fever. Sera from 243 febrile patients were screened for CHIKV IgG and IgM using an immunochromatographic test kit. Clinical and socio-demographic variables were collected using a structured questionnaire. Recent CHIKV infection was observed in 5.8% of the study participants while 25.1% had IgG antibodies demonstrating previous infection. Significant associations were observed between seropositivity and age of participants (p < 0.001), sex (p = 0.044), marital status (p = 0.002), and occupation (p < 0.001). Clinical symptoms such as fever, joint pain, and headache were significantly associated with seropositivity. This study identified recent CHIKV infection in Anyigba. Therefore, there is need for routine screening of febrile patients and molecular characterization to determine the nature of circulating strains.

Anti-annexin V autoantibodies and vascular abnormalities in systemic sclerosis: a longitudinal study

Abstract Background: Annexins are a group of conserved proteins which exert several regulatory functions on various cellular activities. Increased frequency and levels of antibodies against annexin V have already been observed in several autoimmune diseases including systemic sclerosis (SSc), but their role as a vascular biomarker is unknown. The aim of this study was to determine the serum levels and the dynamical behavior of anti-annexin V antibodies over a 24 months follow-up in patients with SSc. Methods: In this bicentric cross-sectional study, 70 patients with SSc were consecutively selected from March 2016 to April 2017. Demographic and clinical features, including the presence of active DUs, were collected. Serum anti-annexin V IgG and IgM antibodies were measured at baseline and after 6, 12 and 24 months of follow-up. Videocapillaroscopy was performed in all patients. Results: Among the 70 SSc patients included anti-annexin V IgG was found in 11 patients (15.7%) (range of 15.88-39.48 U/mL) and anti-annexin V IgM in 10 patients (14.3%) (range of 14.16-22.69 U/mL) at baseline. During follow-up, the number of patients who were positive for anti-annexin V IgG and IgM remained stable over 24 months. Among the patients with positive anti-annexin V IgG at baseline the frequency of patients with necrosis or amputation of extremities, forced vital capacity less than 70% and pulmonary arterial hypertension (PAH) was significantly higher than in patients with negative anti-annexin V IgG antibodies. Patients with anti-annexin V IgG had also a higher Raynaud's Condition Score and a higher Health Assessment Questionnaire Disability Index (HAQ-DI) than patients without these antibodies at baseline. Patients with positive anti-annexin V IgM at baseline presented a higher frequency of PAH, compared to those with negative anti-annexin V IgM at baseline. Conclusions: Anti-annexin V antibodies are stable and do not change their positivity during a 24 month follow-up in SSc patients. Anti-annexin V IgG was associated with more severe interstitial lung involvement and digital microangiopathy, and patients with anti-annexin V IgG or IgM had a higher occurrence of PAH indicating an association of these biomarker with more severe disease.(AU)

Seroprevalence of arenavirus and hantavirus in indigenous populations from the Caribbean, Colombia

Abstract INTRODUCTION: In Colombia, there is insufficient epidemiological surveillance of zoonotic hemorrhagic viruses. METHODS: We performed a sero-epidemiological study in indigenous populations of Wayuü, Kankuamos, and Tuchin communities using Maciel hantavirus and Junin arenavirus antigens for IgG detection by ELISA. RESULTS IgG antibodies to hantavirus and arenavirus were found in 5/506 (1%) and 2/506 (0.4%) serum samples, respectively. CONCLUSIONS: Arenavirus and hantavirus circulate in indigenous populations from the Colombian Caribbean region, and the results indicate that the indigenous populations are exposed to these zoonotic agents, with unknown consequences on their health, despite low seroprevalence.

Development of an enzyme-linked immunosorbent assay for diagnosis of human herpesvirus-7 infection

Abstract INTRODUCTION: Human herpesvirus (HHV)-7 establishes a latent infection during the lifetime of the host and can reactivate after the primary infection, leading to lytic replication in immunosuppressed patients. METHODS: This study aimed to develop an enzyme-linked immunosorbent assay (ELISA) to identify HHV-7 serum antibodies and compare its performance with that of an indirect immunofluorescence assay (IFA). RESULTS: Serum samples (n=102) were tested by IgG-IFA and by ELISA. IFA and ELISA showed IgG-positive results in 77 and 73 samples, respectively. Qualitative concordance of 96% was demonstrated between the two techniques. CONCLUSIONS: ELISA may be useful to diagnose HHV-7 infection.

Seroprevalence of toxoplasmosis in pregnant women and its associated factors among hospital and community populations in Lambayeque, Peru

Abstract INTRODUCTION Toxoplasmosis is a zoonosis caused by Toxoplasma gondii. This study investigated the prevalence and factors associated with toxoplasmosis among pregnant women. METHODS We followed an analytical observational study. From July 2016 to June 2017, 218 pregnant women were selected. The infection was detected through serological dosage of anti-T.gondii Immunoglobulin(Ig) M and IgG antibodies. RESULTS The seroprevalence was 35.8%; the factors associated with infection were consumption of non-drinking water, residence in an urban area, and threatened abortion during the current pregnancy. CONCLUSIONS The seroprevalence of toxoplasmosis among pregnant women is high. The risk factors are dependent on environmental determinants.

Durability of neutralizing antibodies and T-cell response post SARS-CoV-2 infection / 医学前沿

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4

Clinical characteristics and plasma antibody titer of patients with COVID-19 in Zhejiang, China / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first affected humans in China on December 31, 2019 (Shi et al., 2020). Coronaviruses generally cause mild, self-limiting upper respiratory tract infections in humans, such as the common cold, pneumonia, and gastroenteritis (To et al., 2013; Berry et al., 2015; Chan et al., 2015). According to the Report of the World Health Organization (WHO)-China Joint Mission on COVID-19 (WHO, 2020), the case fatality rate of COVID-19 increases with age, while the rate among males is higher than that among females (4.7% and 2.8%, respectively). Since an effective vaccine and specific anti-viral drugs are still under development, passive immunization using the convalescent plasma (CP) of recovered COVID-19 donors may offer a suitable therapeutic strategy for severely ill patients in the meantime. So far, several studies have shown therapeutic efficacy of CP transfusion in treating COVID-19 cases. A pilot study first reported that transfusion of CP with neutralizing antibody titers above 1:640 was well tolerated and could potentially improve clinical outcomes through neutralizing viremia in severe COVID-19 cases (Chen et al., 2020). Immunoglobulin G (IgG) and IgM are the most abundant and important antibodies in protecting the human body from viral attack (Arabi et al., 2015; Marano et al., 2016). Our study aimed to understand the aspects of plasma antibody titer levels in convalescent patients, as well as assessing the clinical characteristics of normal, severely ill, and critically ill patients, and thus provide a basis for guiding CP therapy. We also hoped to find indicators which could serve as a reference in predicting the progression of the disease.

Diagnostic characteristics of serological-based COVID-19 testing: a systematic review and meta-analysis

Serologic testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) promises to assist in assessing exposure to and confirming the diagnosis of coronavirus disease 2019 (COVID-19), and to provide a roadmap for reopening countries worldwide. Considering this, a proper understanding of serologic-based diagnostic testing characteristics is critical. The aim of this study was to perform a structured systematic review and meta-analysis to evaluate the diagnostic characteristics of serological-based COVID-19 testing. Electronic searches were performed using Medline (PubMed), EMBASE, and Cochrane Library. Full-text observational studies that reported IgG or IgM diagnostic yield and used nucleic acid amplification tests (NAATs) of respiratory tract specimens, as a the reference standard in English language were included. A bivariate model was used to compute pooled sensitivity, specificity, positive/negative likelihood ratio (LR), diagnostic odds ratio (OR), and summary receiver operating characteristic curve (SROC) with corresponding 95% confidence intervals (CIs). Five studies (n=1,166 individual tests) met inclusion criteria. The pooled sensitivity, specificity, and diagnostic accuracy for IgG was 81% [(95% CI, 61-92);I2=95.28], 97% [(95% CI, 78-100);I2=97.80], and 93% (95% CI, 91-95), respectively. The sensitivity, specificity, and accuracy for IgM antibodies was 80% [(95% CI, 57-92);I2=94.63], 96% [(95% CI, 81-99);I2=92.96] and 95% (95% CI, 92-96). This meta-analysis demonstrates suboptimal sensitivity and specificity of serologic-based diagnostic testing for SARS-CoV-2 and suggests that antibody testing alone, in its current form, is unlikely to be an adequate solution to the difficulties posed by COVID-19 and in guiding future policy decisions regarding social distancing and reopening of the economy worldwide.

Serological occurrence for tick-borne agents in beef cattle in the Brazilian Pantanal / Ocorrência sorológica para agentes transmitidos por carrapatos em bovinos de corte no Pantanal Brasileiro

Abstract This study investigated the seropositivity for five different tick-borne agents, namely Anaplasma marginale, Babesia bovis, Babesia bigemina, Coxiella burnetii, Anaplasma phagocytophilum, and Trypanosoma vivax in beef cattle in the Brazilian Pantanal. The serum samples collected from animals (200 cows; 200 calves) were used in indirect enzyme-linked immunosorbent assays (iELISA) to detect IgG antibodies against A. marginale, B. bovis, B. bigemina, and T. vivax, and Indirect Fluorescent Antibody Test (IFAT) for detecting IgG antibodies against C. burnetii and A. phagocytophilum. No correlation was observed between seropositivity for C. burnetii and A. phagocytophilum with other agents whereas moderate correlation was observed for A. marginalexB. bigemina x B. bovis. Cows were more seropositive for T. vivax whereas calves were more seropositive for B. bovis and B. bigemina. The highest number of seropositive animals by a single agent was observed for T. vivax (15.2%). Co-seropositivity for T. vivax + A. marginale was higher in cows (25.5%) and for T. vivax + B. bovis + B. bigemina + A. marginale was higher in calves (57.5%). The high seropositivity correlation for A. marginale x B. bovis x B. bigemina is probably due to the presence of the tick biological vector, Rhipicephalus microplus, in the studied farms. Common transmission pathways, mediated by hematophagous dipterans and fomites, may explain the high co-seropositivity of cows for A. marginale and T. vivax. Low seropositivity to C. burnetii is probably due to the type of breeding system employed (extensive). Seropositivity for A. phagocytophilum in only one animal suggests the occurrence of a cross-serological reaction with another agent of the genus Anaplasma.

Resumo Este estudo teve como objetivo determinar a co-soropositividade para agentes transmitidos por carrapatos, como Anaplasma marginale, Babesia bovis, Babesia bigemina, Coxiella burnetii, Anaplasma phagocytophilum, e Trypanosoma vivax em bovinos de corte do Pantanal Brasileiro. Amostras de soro foram colhidas de 400 animais (200 vacas; 200 bezerros) e submetidas a Ensaios Imunoenzimáticos Indiretos (iELISA) para detecção de anticorpos IgG anti- A. marginale, anti- B. bovis, anti- B. bigemina e anti- T. vivax, e à Reação de Imunofluorescência Indireta (RIFI) para detecção de anticorpos IgG anti -C. burnetii e anti- A. phagocytophilum. Ausência de correlação foi vista entre os animais soropositivos para C. burnetii e A. phagocytophilum com os outros agentes e correlação moderada ocorreu entre A. marginale x B. bigemina x B. bovis. Vacas foram mais soropositivas que bezerros para T. vivax e bezerros mais soropositivos que vacas para B. bovis e B. bigemina. Maior número de animais soropositivos para um único agente foi visto para T. vivax (15,2%). Vacas demonstraram maior co-soropositividade para T. vivax + A. marginale (25,5%) e bezerros para T. vivax + B. bovis + B. bigemina + A. marginale (57,5%). A alta correlação entre a soropositividade para A. marginale x B. bovis x B. bigemina é provavelmente devida à presença do vetor biológico, o carrapato Rhipicephalus microplus, nas fazendas estudadas. As vias de transmissão comuns, mediadas por dípteros hematófagos e fômites, podem explicar a alta co-soropositividade das vacas para A. marginale e T. vivax. A baixa soropositividade para C. burnetii é provavelmente devida ao tipo de sistema de criação empregado (extenso). A soropositividade para A. phagocytophilum em apenas um animal sugere a ocorrência de reação sorológica cruzada com outro agente do gênero Anaplasma.

Serological evaluation of Neospora caninum in pregnant women treated at referral center for prenatal screening in Mato Grosso do Sul, Brazil / Avaliação sorológica de Neospora caninum em gestantes atendidas em centro de referência para triagem pré-natal em Mato Grosso do Sul, Brasil

Abstract Neospora caninum is an obligate intracellular protozoan with canids (Canis domesticus, Canis lupus dingo, Canis latrans, Canis lupus) as its definitive hosts. The objective of this study was to detect anti-N. caninum antibodies in pregnant women seen at referral center for prenatal screening in the state of state Mato Grosso do Sul, Brazil. A total of 188 serum samples from pregnant women provided by the Instituto de Pesquisa, Ensino e Diagnósticos da APAE de Campo Grande (IPED/ APAE) were subjected to IFA test and western blot analysis. The samples were divided into three groups: 23/99 samples from the seropositive group for toxoplasmosis were positive for anti-N. caninum IgG antibodies, and 9/99 positive for IgM; in the HIV group, 7/33 were positive for IgG; and in the HIV+toxoplasmosis group, 13/56 were positive for IgG and two positive for IgM. The seropositivity for IgG was assessed by western blot by testing 43 IFA test positive samples using rNcSRS2 (Nc-p43) as antigen. The serological results of the present study suggest that exposure of these pregnant women to the parasite N. caninum and presence of IgM antibodies are indicative of recent infection. Further studies are needed to establish the possibility of active infection.

Resumo Neospora caninum é um protozoário intracelular obrigatório que possui os canídeos (Canis domesticus, Canis lupus dingo, Canis latrans, Canis lupus) como seus hospedeiros definitivos. O objetivo deste trabalho foi detectar anticorpos anti-N. caninum em gestantes, atendidas em centro de referência para triagem pré-natal, em Mato Grosso do Sul, Brasil. Um total de 188 amostras de soro de gestantes, cedidas pelo Instituto de Pesquisa, Ensino e Diagnósticos da APAE de Campo Grande (IPED/ APAE), foram submetidas ao teste de RIFI e western blot para a detecção de anticorpos anti-N. caninum. As amostras foram divididas em três grupos: 23/99 amostras do grupo soropositivo para toxoplasmose demonstraram positividade para anticorpos IgG anti-N. caninum e 9/99 positivos para IgM. No grupo HIV 7/33 apresentaram positividade para IgG. No grupo HIV+Toxoplasmose 13/56 apresentaram positividade para IgG e duas para IgM. A soropositividade para IgG foi avaliada por western blot, testando 43 amostras positivas para RIFI, usando-se rNcSRS2 (Nc-p43) como antígeno. Os resultados sorológicos do presente estudo sugerem exposição dessas gestantes ao parasita N. caninum e a positividade para anticorpos IgM são indicativos de infecção recente. Mais estudos na área são necessários para estabelecer a possibilidade de infecção ativa.

Seroprevalence of varicella antibodies in adults without clinical history of disease / Soroprevalência de anticorpos antivaricela em adultos sem história clínica da doença / Seroprevalencia de anticuerpos frente a la varicela en adultos sin historial clínico de la enfermedad

Abstract: Varicella in adults and immunocompromised patients can be severe. The clinical diagnosis of varicella has high accuracy and the history of disease has a high positive predictive value for protection. A significant portion of adults, however, cannot remember if they have had varicella, especially older individuals. We conducted a cross-sectional study to determine the seroprevalence of varicella protective antibodies titers in adults with no clinical history of disease, attended at a Reference Center for Special Immunobiologicals and Travel Medicine in Rio de Janeiro (Brazil). Titration of immunoglobulin G (IgG) antibodies to varicella-zoster was determined by chemiluminescence immunoassay. Among 140 adults without history of varicella, 92% had protective antibody titers. We concluded that seroprevalence of varicella-zoster protection was very high in adults with negative history of disease and the use of serology before vaccination reduced significantly unnecessary vaccine and immunoglobulin use.

Resumo: A varicela é uma doença potencialmente grave em adultos e em pacientes imunocomprometidos. O diagnóstico clínico da varicela apresenta alta acurácia, e o relato da doença na história individual tem alto valor preditivo positivo para a proteção. Entretanto, uma proporção significativa de adultos, principalmente os mais idosos, não se lembra se já teve a doença. Realizamos um estudo transversal para determinar a soroprevalência de títulos protetores de anticorpos contra a varicela em adultos sem história clínica da doença, atendidos em um Centro de Referência para Imunobiológicos Especiais e Medicina de Viagem no Rio de Janeiro, Brasil. Os títulos da imunoglobulina G (IgG) contra varicela-zoster foram determinados por quimiluminescência. Entre 140 adultos sem história de varicela, 92% apresentaram títulos protetores de anticorpos. Concluímos que a soroprevalência de proteção contra varicela-zoster é muito alta em adultos sem história da doença, e que o uso de teste sorológico antes da vacinação reduziria significativamente a vacinação desnecessária e o uso de imunoglobulina.

Resumen: La varicela en adultos y pacientes inmunocomprometidos puede ser grave. El diagnóstico clínico de la varicela tiene una gran precisión y la historia de la enfermedad cuenta con un alto valor predictivo positivo para la protección contra ella. Sin embargo, un porcentaje significativo de adultos, no puede recordar si tuvieron varicela, especialmente las personas más viejas. Realizamos un estudio transversal para determinar la seroprevalencia de las concentraciones de anticuerpos protectores frente a la varicela, en adultos sin historia clínica de la enfermedad, que se llevó a cabo en un Centro de Referencia para Inmunobiología Especial y Medicina del Viajero en Río de Janeiro (Brasil). Se determinó la valoración de los anticuerpos de inmunoglobulina G (IgG) a la varicela-zoster mediante un ensayo inmunológico quimioluminiscente. Entre 140 adultos sin historial de varicela, un 92% tuvieron concentraciones de anticuerpos protectores. Concluimos que la seroprevalencia de la protección a la varicela-zoster fue muy alta en adultos con un historial negativo de la enfermedad y la utilización de la serología antes de la vacunación redujo de manera significativa la vacunación innecesaria y el uso de la inmunoglobulina.

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.

Pseudotumor retroperitoneal como apresentação de doença relacionada à IgG 4: relato de caso / Retroperitoneal pseudotumor as a presentation of IgG4-related disease: a case report

Apresentamos um caso de doença relacionada à IgG4 devido às suas várias formas de apresentação clínica e dificuldades diagnósticas, objetivando acrescentar à literatura científica essa apresentação atípica. Trata-se de um homem de 65 anos com dor abdominal, febre e sintomas urinários. Exames laboratoriais inocentes para processo infeccioso agudo. Em tomografia computadorizada de abdome, evidenciou-se pseudotumor em região retroperitoneal, envolvendo ureter, veia e artéria ilíacas. Foi submetido à ressecção cirúrgica, tendo sido confirmado o diagnóstico de doença relacionada à IgG4 pela imuno-histoquímica. Iniciou tratamento com glicocorticoide com melhora clínica importante, seguindo em acompanhamento ambulatorial.

This is a case report of IgG4-related disease because of its wide variety of clinical presentations and difficulties in diagnosis, aiming at adding this atypical presentation to scientific literature. It is a case of a 65-year-old man with abdominal pain, fever and urinary symptoms. Laboratory tests were naive for acute infectious processes. In a computed tomography of the abdomen, retroperitoneal pseudotumor involving ureter, and iliac vein and artery was found. The patient underwent surgical resection, and the diagnosis of IgG4-related disease was confirmed by immunohistochemistry. The treatment was begun with glucocorticoids, with important clinical improvement. He was followed in outpatient settings.