Several studies suggest that children infected with SARS-CoV-2 have fewer clinical manifestations than adults; when they develop symptoms, they rarely progress to severe disease. Different immunological theories have been proposed to explain this phenomenon. In September 2020, 16% of the active COVID-19 cases in Venezuela were children under 19 years. We conducted a cross-sectional study of pediatric patients’ immune response and clinical conditions with SARS-CoV-2 infection. The patients were admitted to the COVID-19 area of the emergency department of Dr José Manuel de los Ríos Children’s Hospital (2021–2022). The lymphocyte subpopulations were analyzed by flow cytometry, and IFNγ, IL-6, and IL-10 serum concentrations were quantified using commercial ELISA assays. The analysis was conducted on 72 patients aged one month to 18 years. The majority, 52.8%, had mild disease, and 30.6% of the patients were diagnosed with MIS-C. The main symptoms reported were fever, cough, and diarrhea. A correlation was found between IL-10 and IL-6 concentrations and age group, lymphocyte subpopulations and nutritional status and steroid use, and IL-6 concentrations and clinical severity. The results suggest a different immune response depending on age and nutritional status that should be considered for treating pediatric COVID-19 patients.

Nutrition is essential in developing and maintaining a robust immune system and is vital for immune homeostasis. The pediatric population is particularly vulnerable to dietary changes, as their growth and development require a high energy intake. Malnutrition in infants can have immediate and long-lasting effects, increasing the risk of morbidity and mortality. Under and overnutrition can slow down the immune response to infections, which can delay recovery. To effectively defend against SARS-CoV-2 infection and enhance viral clearance, it is essential to maintain a healthy diet that includes sufficient macro and micronutrients. Several studies, most of which have been performed in adults, have shown that vitamins such as C, B12, folate, D, and E, as well as the minerals selenium, copper, iron, zinc, and magnesium, can help reduce the symptoms and duration of an infection. Supplementation with micronutrients has been shown to help with childhood malnutrition and can contribute to a more favorable clinical course of COVID-19. In children with obesity, it is also essential to monitor cardiometabolic and thrombotic risks, based on data from studies in adults. This review analyses the impact of the nutritional status of pediatric patients with SARS-CoV-2 infection, its contribution to clinical severity, and potential therapeutic interventions.

Several studies suggest that children infected with SARS-CoV-2 have fewer clinical manifestations than adults; when they develop symptoms, they rarely progress to severe disease. Different immunological theories have been proposed to explain this phenomenon. In September 2020, 16% of the active COVID-19 cases in Venezuela were children under 19 years. We conducted a cross-sectional study of pediatric patients' immune response and clinical conditions with SARS-CoV-2 infection. The patients were admitted to the COVID-19 area of the emergency department of Dr José Manuel de los Ríos Children's Hospital (2021-2022). The lymphocyte subpopulations were analysed by flow cytometry, and IFNγ, IL-6 and IL-10 serum concentrations were quantified using commercial ELISA assays. The analysis was conducted on 72 patients aged one month and 18 years. The majority, 52.8%, had mild disease, and 30.6 % were diagnosed with MIS-C. The main symptoms reported were fever, cough and diarrhoea. A correlation was found between IL-10 and IL-6 concentrations and age group; lymphocyte subpopulations and nutritional status and steroid use; IL-6 concentrations and clinical severity. The results suggest a different immune response depending on age and nutritional status that should be considered for treating pediatric COVID-19 patients.

La COVID-19, es una enfermedad producida por el virus SARS- CoV-2, descubierta por primera vez en diciembre de 2019, en la ciudad de Wuhan, China. Durante la infección se produce una alteración en la respuesta del sistema inmune, lo que conduce a un estado de hiperinflamación que en algunos casos puede generar desenlace fatal para el individuo enfermo. Esta investigación tuvo como objetivos la evaluación del perfil inmunológico celular de pacientes venezolanos infectados con el virus SARS-CoV-2, determinando el porcentaje de expresión de los marcadores de Linfocitos T, Linfocitos T reguladores (Treg), Linfocitos T de memoria, Linfocitos B, Linfocitos B de memoria, células NK y NKt, mediante la técnica de citometría de flujo; así como la determinación de la relación de las citoquinas (IL) IL-6, IL-10 y TNF-α mediante la técnica de ELISA. Encontramos una disminución significativa en la expresión de los marcadores de Linfocitos T y Linfocitos T de memoria en individuos, se observó que las células NK y NkT, aumentan su expresión durante la infección. Adicionalmente se comprobó la existencia de una respuesta de tipo reguladora, especialmente en los individuos con la forma leve de la enfermedad al observarse una correlación positiva entre la expresión de los marcadores CD4+/CD25+/ CD127+ de los Linfocitos T reguladores y la concentración sérica de IL-10 y de TNF-α y la IL-6. Nuestro estudio expone la respuesta dual del sistema inmune al enfrentar al SAR-CoV-2, inferimos que la severidad de la infección estar determinada por los elementos predominantes en balanza inflamación/regulación.

El ensayo de capacidad oxidativa mediante citometría de flujo es un método sensible que evalúa la funcionalidad de los polimorfonucleares. Se basa en cuantificar la oxidación de compuestos fluorescentes, posterior al estallido respiratorio que se produce al tratar a los neutrófilos con agentes estimulantes, que evidencia que la producción de especies reactivas de oxígeno es una respuesta gradual y proporcional al estímulo recibido. El presente estudio evaluó la prevalencia de alteraciones en la capacidad oxidativa de polimorfonucleares mediante citometría de flujo en 65 pacientes venezolanos con sospecha clínica de inmunodeficiencias primarias, que acudieron al Instituto de Inmunología “Dr. Nicolás E. Bianco C” entre noviembre de 2024 y mayo de 2025. Utilizando el ensayo de diclorofluoresceína diacetato (DCFH-DA) estimulado con PMA, se determinó que, aunque el 56,9% de los sujetos mantenía una función normal, un significativo 43,1% presentaba anomalías funcionales. De estos, el 30,8% mostró una respuesta disminuida, mientras que un 12,3% evidenció una afección severa. La muestra fue predominantemente pediátrica (78,46%) con una edad media de 13 años, sin diferencias estadísticas significativas según el sexo. Estos resultados subrayan la importancia de la citometría de flujo como herramienta diagnóstica de referencia en el entorno hospitalario venezolano y concluyen que existe una prevalencia relevante de defectos oxidativos en la población estudiada, aspecto que enfatiza la necesidad de fortalecer los protocolos de detección temprana y los registros epidemiológicos nacionales para mitigar el subdiagnóstico y mejorar el pronóstico clínico de estos pacientes en el país. The oxidative capacity assay by flow cytometry is a sensitive method that evaluates the functionality of polymorphonuclear cells. It is based on quantifying the oxidation of fluorescent compounds following the respiratory burst that occurs when neutrophils are treated with stimulating agents, demonstrating that the production of reactive oxygen species is a gradual response proportional to the stimulus received. The present study evaluated the prevalence of alterations in the oxidative capacity of polymorphonuclear cells via flow cytometry in 65 Venezuelan patients with clinical suspicion of primary immunodeficiencies, who attended the ‘Dr. Nicolás E. Bianco C’ Institute of Immunology between November 2024 and May 2025. Assessed via phorbol myristate acetate (PMA)-stimulated dichlorofluorescein diacetate (DCFH-DA) assay, results indicated that while 56.9% of subjects exhibited normal neutrophil function, a significant 43.1% presented oxidative burst anomalies. Of these, 30.8% showed a diminished response, while 12.3% evidenced severe impairment. The sample was predominantly pediatric (78.46%) with a mean age of 13 years, with no statistically significant differences according to sex. These results underscore the importance of flow cytometry as a gold-standard diagnostic tool in the Venezuelan hospital setting and conclude that there is a relevant prevalence of oxidative defects in the studied population, highlighting the need to strengthen early detection protocols and national epidemiological registries to mitigate underdiagnosis and improve the clinical prognosis of these patients in the country.

Background: Vaccines are crucial for preventing infectious diseases, as both humoral and cellular immune responses play a vital role in combating viral infections. The cellular immune response is crucial against SARS-CoV-2, particularly with the emergence of new variants that evade antibody neutralization. This study focuses on the immune memory response in individuals who have been vaccinated with the Sinopharm BBIBP-CorV vaccine. Methods: A cross-sectional study evaluated lymphocyte subpopulations using flow cytometry in 52 vaccinated adults (30 females, 22 males) who had been exposed to SARS-CoV-2 or diagnosed with COVID-19. Conducted from February to June 2023 during the Omicron variant’s circulation, this study assessed antigens—CD154 in CD4+ T cells, CD107 and CD314 in CD8+ T cells, CD314 in NK cells, and CD86 in CD19 B cells—after stimulation with viral peptides and an inactivated virus. Granzyme B and IFN-γ were quantified using ELISA. Results: The memory response, regardless of gender, age, or Body Mass Index (BMI), was mild but significant upon exposure to a viral antigen or inactivated virus. An increase in the secretion of IFN-γ and granzyme B was also observed. Conclusions: It is suggested that the vaccine was able to generate a mild long-term memory against the SARS-CoV-2 virus in vaccinated adult individuals, independent of gender and BMI.