Electrochemical magneto-immunoassay for detection of zika virus antibody in human serum.

Zika virus (ZIKV) is a flavivirus transmitted by infected Aedes genus mosquitoes. An infected person may be asymptomatic or present symptoms such as fever, arthralgia, and in pregnancy it may lead to neurological disorders in the fetus, such as microcephaly. Based on the high dissemination potential of ZIVK and its similar antigen composition to other arboviruses, new approaches for selective virus detection are urgently needed. This work reports the development of an electrochemical immunoassay for detection of anti-ZIKV antibodies, using magnetic beads functionalized with recombinant protein derived from the non-structural protein 1 (ΔNS1-ZIKV) and anti-IgG antibodies labeled with horseradish peroxidase (HRP) enzyme. The magneto-immunoassay uses disposable microfluidic devices for detection of anti-ZIKV in serum samples. A linear response was obtained for a wide concentration range from 0.01 to 9.80 × 105 pg mL-1 (r2 = 0.982), with a limit of detection of 0.48 pg mL-1. The proposed immunoassay proved to be highly efficient for the detection of anti-ZIKV antibodies in serum, offering promising perspectives for the development of fast, simple, and affordable point-of-care diagnosis devices for ZIKV.

Electrochemical magneto-immunoassay for detection of zika virus antibody in human serum

Zika virus (ZIKV) is a flavivirus transmitted by infected Aedes genus mosquitoes. An infected person may be asymptomatic or present symptoms such as fever, arthralgia, and in pregnancy it may lead to neurological disorders in the fetus, such as microcephaly. Based on the high dissemination potential of ZIVK and its similar antigen composition to other arboviruses, new approaches for selective virus detection are urgently needed. This work reports the development of an electrochemical immunoassay for detection of anti-ZIKV antibodies, using magnetic beads functionalized with recombinant protein derived from the non-structural protein 1 (ΔNS1-ZIKV) and anti-IgG antibodies labeled with horseradish peroxidase (HRP) enzyme. The magneto-immunoassay uses disposable microfluidic devices for detection of anti-ZIKV in serum samples. A linear response was obtained for a wide concentration range from 0.01 to 9.80 × 105 pg mL−1 (r2 = 0.982), with a limit of detection of 0.48 pg mL−1. The proposed immunoassay proved to be highly efficient for the detection of anti-ZIKV antibodies in serum, offering promising perspectives for the development of fast, simple, and affordable point-of-care diagnosis devices for ZIKV.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers.

OBJECTIVES: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. METHODS: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. RESULTS: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. CONCLUSION: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers

Abstract Objectives: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. Methods: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. Results: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. Conclusion: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.

Crise aplástica da anemia falciforme condicionada pelo parvovírus B19 / Aplastic crisis in sickle cell anemia induced by parvovírus B19

Objetivo: Relatar um caso de uma criança de oito meses de idade, portadora de anemia falciforme, que apresenta quadro de crise aplástica transitória condicionada pelo parvovírus B19, salientando a raridade da ocorrência neste grupo etário. Material e métodos: Os autores fazem revisão de literatura e descrevem um caso de uma criança de oito meses, portadora de anemia falciforme, que se apresenta com febre, palidez intensa e reticulocitopenia. Ao ser internada é feita a hipóstese diagnóstica de crise aplástica transitória da anemia falciforme, e é submetida à investigação laboratorial com hemograma e pesquisa para parvovirus B19 através de sorologias por enzima imuno-ensaio (ELISA) e testes para detecção do antigeno por PCR. Resultados: Criança de oito meses de idade com anemia falciforme é admitida no hospital por febre e anemia profunda (HB = 3,8 por cento) e reticulocitopenia (2 por cento) sendo feito diagnóstico de crise aplástica transitória da anemia falciforme. As sorologias para parvovirus B19 mostram Ig M assim como também o PCR. A criança apresentou evolução favorável, recebendo transfusão de concentrado de glóbulos vermelhos e tendo alta após 4 dias. Conclusões: Estes caso ilustra a ocorrência da crise aplástica transitória da anemia falciforme condicionada pelo parvovirus B19 em uma criança com idade bastante precoce, fato pouco comum segundo relatos da literatura mundial e inédito na literatura nacional

Infecçöes virais em crianças internadas por doença aguda no trato respiratório inferior / Viral infections in hospitalized children affected by acute lower respiratory tract disease

Objetivo: Avaliar a freqüência dos principais vírus respiratórios em crianças internadas por doença do trato respiratório inferior em hospital universitário. Métodos: Foi realizado estudo prospectivo que incluiu duas coortes de crianças internadas no período de abril a julho de 1996. Os grupos selecionados segundo a presença de patologia deo trato respiratório inferior: Grupo A - com doença aguda (tempo de história inferior a sete dias), e B-sem patologia respiratória presente ou recente. Os parâmetros para definiçäo de doença do trato respiratório inferior incluíram alteraçöes na propedêutica pulmonar e/ou às radiografias simples do tórax. Foram pré-definidos critérios clínicos e radiológicos para classificaçäo das doenças do trato respiratório inferior no grupo A. Foi coletado, à internaçäo, material da nasofaringe de todas as crianças para detecçäo de vírus, através de cultura em meio celular e por imunofluorescência direta. Resultados: Foram selecionados 201 casos, 126 no grupo A e 75 no grupo B. Foram identificados vírus em 71 crianças do grupo A (56,4 por cento), enquanto eram somente 3 no grupo B (4,0 por cento). Nas crianças do grupo A foi predominante o vírus respiratório sincicial, detectado em 66 casos, sendo também identificados adenovírus (4) e influenza (1) em outros pacientes. No grupo B foram identificados dois pacientes com vírus respiratório sincicial e um com adenovírus. Os pacientes do grupo A que apresentavam vírus respiratório sincicial tinham mediana de idade (3 meses) menor do que os outros casos deste grupo (13 meses) e apresentavam mais sibilância ao exame físico (78,7 por cento versus 33,3 por cento). Este vírus esteve associado à maior parte dos casos de broquiolite (84 por cento) e à metade das pneumonias (46,4 por cento). Conclusöes: Os autores constataram uma significativa presença de vírus na maior parte dos casos de crianças internadas com patologia aguda do trato respitatório inferior...