Timeline analysis of IgA and IgG levels in Covid-19 hospitalized patients according to the clinical outcome / Análise temporal das concentrações de IgA e IgG em pacientes hospitalizados com Covid-19 de acordo com o desfecho clínico

ABSTRACT Introduction: Studies suggest the association between antibody production and the severity of coronavirus disease 2019 (Covid-19). Objectives: To evaluate the concentrations of immunoglobulins class A (IgA) and class G (IgG) during the hospitalization period of Covid-19 patients according to the outcome (survival vs death). Materials and methods: Patients with severe acute respiratory syndrome of coronavirus 2 (Sars-CoV-2) infection confirmed by reverse transcriptase reaction followed by polymerase chain reaction (RT-PCR) were included in this prospective study. Samples were obtained weekly during the follow-up of individuals, considering symptom onset. Titers of anti-Sars-CoV-2 IgA and IgG were measured using a commercial immunoassay. Correlations between IgA/IgG and cycle threshold (Ct) values for N1 and N2 target genes were also assessed. Results: We studied 55 Covid-19 patients (59.7±16.2 years, 63.6% male), of which 28 (50.9%) died. We observed IgA and IgG positivity (IgA+ and IgG+) in 90.9% and 80% of patients, respectively. The highest IgA+ frequency was observed at weeks 2 and 3 and the highest IgG+ at weeks 3 and 4. It is important to note that patients who died presented lower IgA titers in the first two weeks (p < 0.05); however, a significant increase in IgA levels was observed in the subsequent weeks. Lastly, we identified that significant correlations between Ct values and immunoglobulins levels, both IgA and IgG were correlated with Ct N2 in patients who died. Conclusion: Our results suggest that lower IgA titers in early Covid-19, which is associated with lower Ct values, may indicate patients at higher risk for death.

RESUMEN Introducción: Los estudios sugieren una asociación entre la producción de anticuerpos y la gravedad de la enfermedad por coronavirus 2019 (Covid-19). Objetivos: Evaluar las concentraciones de inmunoglobulinas clase A (IgA) y clase G (IgG) durante la hospitalización de pacientes con Covid-19 según el desenlace (supervivencia vs muerte). Materiales y métodos: Se incluyeron en este estudio prospectivo pacientes con síndrome respiratorio agudo severo de infección por coronavirus 2 (Sars-CoV-2) confirmado por la reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR). Las muestras se obtuvieron semanalmente durante el seguimiento de los individuos, considerando la aparición de los síntomas. Los títulos de IgA e IgG anti-Sars-CoV-2 se midieron usando un inmunoensayo comercial. También se evaluaron las correlaciones entre IgA/IgG y los valores de los umbrales de ciclo [cycle threshold (Ct)] para los genes N1 y N2. Resultados: Se estudiaron 55 pacientes Covid-19 (59,7 ± 16,2 años, 63,6% varones), de los cuales 28 (50,9%) fallecieron. Observamos positividad de IgA e IgG (IgA+ e IgG+) en el 90,9% y el 80% de los pacientes, respectivamente. La frecuencia más alta de IgA+ se observó en las semanas dos y tres y la IgG + más alta en las semanas tres y cuatro. Es importante señalar que los pacientes que fallecieron presentaron títulos de IgA más bajos en las dos primeras semanas (p < 0,05); sin embargo, se observó un aumento significativo en los niveles de IgA en las semanas siguientes. Conclusión: Identificamos correlaciones significativas entre los valores de Ct y los niveles de Ig, tanto IgA como IgG se correlacionaron con Ct N2 en los pacientes que fallecieron. Nuestros resultados sugieren que los títulos de IgA más bajos en Covid-19 temprano, que se asocia con valores de Ct más bajos, pueden indicar que los pacientes tienen un mayor riesgo de muerte.

RESUMO Introdução: Estudos sugerem a associação entre a produção de anticorpos e a gravidade da coronavirus disease 2019 (Covid-19). Objetivos: Avaliar as concentrações de imunoglobulinas da classe A (IgA) e da classe G (IgG) durante a internação de pacientes com Covid-19 de acordo com o desfecho (sobrevida vs óbito). Materiais e métodos: Pacientes com infecção pela síndrome respiratória aguda grave do coronavírus 2 (Sars-CoV-2) confirmada por reação da transcriptase reversa seguida de reação em cadeia da polimerase (RT-PCR) foram incluídos neste estudo prospectivo. As amostras foram obtidas semanalmente durante o acompanhamento dos indivíduos, considerando o início dos sintomas. Os títulos de IgA e IgG anti-Sars-CoV-2 foram mensurados por meio de um imunoensaio comercial. Correlações entre IgA/IgG e valores de limiar de detecção [cycle thresholds (Ct)] para os genes alvos N1 e N2 também foram avaliadas. Resultados: Estudamos 55 pacientes com Covid-19 (59,7 ± 6,2 anos; 63,6% do sexo masculino); destes, 28 (50,9%) morreram. Observamos positividade para IgA e IgG (IgA+/IgG+) em 90,9% e 80% dos pacientes, respectivamente. A maior frequência de IgA+ foi verificada nas semanas 2 e 3, e a maior frequência de IgG+, nas semanas 3 e 4. É importante observar que os pacientes que morreram apresentaram títulos de IgA mais baixos nas primeiras duas semanas (p < 0,05); no entanto, um aumento significativo na concentração de IgA foi observado nas semanas subsequentes. Por fim, identificamos correlações significativas entre os valores de Ct e imunoglobulinas; tanto IgA quanto IgG foram correlacionadas com Ct N2 em pacientes que morreram. Conclusão: Nossos resultados sugerem que títulos mais baixos de IgA no início da Covid-19 - que estão associados a valores mais baixos de Ct - podem indicar pacientes com risco elevado de evoluir para óbito.

CD64 expression on polymorphonuclear cells as a potential marker for monitoring the human cytomegalovirus replication after kidney transplantation / Expressão de CD64 em polimorfonucleares como potencial marcador para o monitoramento da replicação do citomegalovírus humano após transplante renal

ABSTRACT Human cytomegalovirus (HCMV) infection is the main cause of morbidity in kidney transplant recipients. This study aims to investigate if CD64 expression on polymorphonuclear (PMN) cells is useful for the detection of HCMV infection in eleven kidney recipients during sixty days. From the total patients, nine were positive for both pp65 antigenemia and HCMV by quantitative polymerase chain reaction (qPCR), all of which had circulating neutrophils expressing CD64 3-4 weeks prior to pp65 antigenemia peak. These results suggest that quantification of PMN CD64 together with pp65 antigenemia could be useful for the early diagnosis of HCMV after transplantation.

RESUMO A infecção por citomegalovírus humano (CMVH) é a principal causa de morbidade em receptores de transplante renal. Este estudo pretende investigar se a expressão de CD64 em polimorfonucleares (PMN) é útil para a detecção de infecção por CMVH em 11 receptores renais durante 60 dias. Do total de pacientes, nove foram positivos para antigenemia pp65 e para CMVH por reação em cadeia da polimerase quantitativa (qPCR), todos apresentando neutrófilos circulantes que expressam CD64 3-4 semanas antes do pico de antigenemia pp65. Esses resultados sugerem que a quantificação de PMN CD64 em conjunto com a antigenemia pp65 pode ser útil para o diagnóstico precoce de HCMV no pós-transplante.

Virulence Markers and Phylogenetic Analysis of Escherichia coli Strains with Hybrid EAEC/UPEC Genotypes Recovered from Sporadic Cases of Extraintestinal Infections.

Virulence genes from different E. coli pathotypes are blended in hybrid strains. E. coli strains with hybrid enteroaggregative/uropathogenic (EAEC/UPEC) genotypes have sporadically emerged causing outbreaks of extraintestinal infections, however their association with routine infections is yet underappreciated. We assessed 258 isolates of E. coli recovered from 86 consecutive cases of extraintestinal infections seeking EAEC and hybrid genotype (EAEC/UPEC) strains. Extensive virulence genotyping was carried out to detect 21 virulence genes, including molecular predictors of EAEC and UPEC strains. Phylogenetic groups and sequence types (STs) were identified, as well as it was performed phylogenetic analyses in order to evaluate whether hybrid EAEC/UPEC strains belonged to intestinal or extraintestinal lineages of E. coli. Adhesion assays were performed to evaluate the biofilm formation by hybrid strains in human urine and cell culture medium (DMEM). Molecular predictors of UPEC were detected in more than 70% of the strains (chuA in 85% and fyuA in 78%). Otherwise, molecular predictors of EAEC (aatA and aggR) were detected in only 3.4% (9/258) of the strains and always along with the UPEC predictor fyuA. Additionally, the pyelonephritis-associated pilus (pap) gene was also detected in all of the hybrid EAEC/UPEC strains. EAEC/UPEC strains were recovered from two cases of community-onset urinary tract infections (UTI) and from a case of bacteremia. Analyses revealed that hybrid EAEC/UPEC strains were phylogenetically positioned in two different clades. Two representative strains, each recovered from UTI and bacteremia, were positioned into a characteristic UPEC clade marked by strains belonging to phylogenetic group D and ST3 (Warwick ST 69). Another hybrid EAEC/UPEC strain was classified as phylogroup A-ST478 and positioned in a commensal clade. Hybrid EAEC/UPEC strains formed biofilms at modest, but perceptible levels either in DMEM or in urine samples. We showed that different lineages of E. coli, at least phylogenetic group A and D, can acquire and gather EAEC and UPEC virulence genes promoting the emergence of hybrid EAEC/UPEC strains.