Pre-existing cell populations with cytotoxic activity against SARS-CoV-2 in people with HIV and normal CD4/CD8 ratio previously unexposed to the virus.

Introduction: HIV-1 infection may produce a detrimental effect on the immune response. Early start of antiretroviral therapy (ART) is recommended to preserve the integrity of the immune system. In fact, people with HIV (PWH) and normal CD4/CD8 ratio appear not to be more susceptible to severe forms of COVID-19 than the general population and they usually present a good seroconversion rate in response to vaccination against SARS-CoV-2. However, few studies have fully characterized the development of cytotoxic immune populations in response to COVID-19 vaccination in these individuals. Methods: In this study, we recruited PWH with median time of HIV-1 infection of 6 years, median CD4/CD8 ratio of 1.0, good adherence to ART, persistently undetectable viral load, and negative serology against SARS-CoV-2, who then received the complete vaccination schedule against COVID-19. Blood samples were taken before vaccination against COVID-19 and one month after receiving the complete vaccination schedule. Results: PWH produced high levels of IgG against SARS-CoV-2 in response to vaccination that were comparable to healthy donors, with a significantly higher neutralization capacity. Interestingly, the cytotoxic activity of PBMCs from PWH against SARS-CoV-2-infected cells was higher than healthy donors before receiving the vaccination schedule, pointing out the pre-existence of activated cell populations with likely unspecific antiviral activity. The characterization of these cytotoxic cell populations revealed high levels of Tgd cells with degranulation capacity against SARS-CoV-2-infected cells. In response to vaccination, the degranulation capacity of CD8+ T cells also increased in PWH but not in healthy donors. Discussion: The full vaccination schedule against COVID-19 did not modify the ability to respond against HIV-1-infected cells in PWH and these individuals did not show more susceptibility to breakthrough infection with SARS-CoV-2 than healthy donors after 12 months of follow-up. These results revealed the development of protective cell populations with broad-spectrum antiviral activity in PWH with normal CD4/CD8 ratio and confirmed the importance of early ART and treatment adherence to avoid immune dysfunctions.

Sustained Cytotoxic Response of Peripheral Blood Mononuclear Cells from Unvaccinated Individuals Admitted to the ICU Due to Critical COVID-19 Is Essential to Avoid a Fatal Outcome.

The main objective of this study was to determine the influence of the cytotoxic activity of peripheral blood mononuclear cells (PBMCs) on the outcome of unvaccinated individuals with critical COVID-19 admitted to the ICU. Blood samples from 23 individuals were collected upon admission and then every 2 weeks for 13 weeks until death (Exitus group) (n = 13) or discharge (Survival group) (n = 10). We did not find significant differences between groups in sociodemographic, clinical, or biochemical data that may influence the fatal outcome. However, direct cellular cytotoxicity of PBMCs from individuals of the Exitus group against pseudotyped SARS-CoV-2-infected Vero E6 cells was significantly reduced upon admission (-2.69-fold; p = 0.0234) and after 4 weeks at the ICU (-5.58-fold; p = 0.0290), in comparison with individuals who survived, and it did not improve during hospitalization. In vitro treatment with IL-15 of these cells did not restore an effective cytotoxicity at any time point until the fatal outcome, and an increased expression of immune exhaustion markers was observed in NKT, CD4+, and CD8+ T cells. However, IL-15 treatment of PBMCs from individuals of the Survival group significantly increased cytotoxicity at Week 4 (6.18-fold; p = 0.0303). Consequently, immunomodulatory treatments that may overcome immune exhaustion and induce sustained, efficient cytotoxic activity could be essential for survival during hospitalization due to critical COVID-19.

Early Cellular and Humoral Responses Developed in Oncohematological Patients after Vaccination with One Dose against COVID-19.

Individuals with oncohematological diseases (OHD) may develop an impaired immune response against vaccines due to the characteristics of the disease or to its treatment. Humoral response against SARS-CoV-2 has been described to be suboptimal in these patients, but the quality and efficiency of the cellular immune response has not been yet completely characterized. In this study, we analyzed the early humoral and cellular immune responses in individuals with different OHD after receiving one dose of an authorized vaccine against SARS-CoV-2. Humoral response, determined by antibodies titers and neutralizing capacity, was overall impaired in individuals with OHD, except for the cohort of chronic myeloid leukemia (CML), which showed higher levels of specific IgGs than healthy donors. Conversely, the specific direct cytotoxic cellular immunity response (DCC) against SARS-CoV-2, appeared to be enhanced, especially in individuals with CML and chronic lymphocytic leukemia (CLL). This increased cellular immune response, developed earlier than in healthy donors, showed a modest cytotoxic activity that was compensated by significantly increased numbers, likely due to the disease or its treatment. The analysis of the immune response through subsequent vaccine doses will help establish the real efficacy of COVID-19 vaccines in individuals with OHD.

MUCOSAL anti-infections vaccines: Beyond conventional vaccines. / Vacunas antiinfecciosas de mucosas en la profilaxis de infecciones recurrentes: más allá de las vacunas convencionales.

An urgent search is currently underway for alternatives to antibiotics to prevent infections, due to the accelerated evolution and increase in antibiotic resistance. This problem is more serious for patients with recurrent infections, since they have to use many cycles of antibiotics per year, so the risk for antibiotic resistance is higher and can be life-threatening. In recent years, the use of prophylactic vaccines via the mucosal route for these patients with recurrent infections has been demonstrated as a potentially beneficial and safe alternative to prevent infections. The new knowledge about mucosal immunity and trained immunity, a form of innate immunity memory that can enhance the response to different infectious threads, has made it easier to extend its use. The application of the new concepts of trained immunity may explain the simultaneous pro-tolerogenic and boosting effect or effects of these drugs on diverse immune cells for different infections. In this review, we describe the immunomodulatory mechanisms of mucosal polybacterial vaccines and their connection with trained immunity and its utility in the prevention of recurrent infections in immunosuppressed patients.

Hiperinsulinismo congénito por mutación del gen ABCC8 / Congenital hyperinsulinism due to the ABCC8 gene mutation / Hiperinsulinismo congênito causado por mutação do gen ABCC8

Resumen: El hiperinsulinismo congénito es la causa más común de hipoglucemia persistente en el recién nacido y la infancia, con un alto riesgo de daño neurológico irreversible. En los últimos años, gracias a los avances en el conocimiento de la genética molecular, se ha avanzado y profundizado en sus bases genéticas; sin embargo, el diagnóstico se sigue realizando en muchas ocasiones demasiado tarde, dada la heterogeneidad que presenta esta enfermedad. Se detalla a continuación el caso de una paciente con hipoglicemias de difícil control desde el nacimiento, secundaria a hiperinsulinismo congénito y en cuyo estudio genético se evidenció mutación del gen ABCC8.

Summary: Congenital hyperinsulinism (CH) is the most common cause of persistent hypoglycemia in newborns and children at a high risk of irreversible neurological damage. In spite of the recent progress made by the molecular genetics' genetic base, diagnosis is still often late, given the heterogeneity of this disease. We hereby report the case of a patient ranging from secondary and difficult to control hypoglycemia to congenital hyperinsulinemia. Her genetic test showed ABCC8 gene mutation.

Resumo: O hiperinsulinismo congênito (HC) é a causa mais comum de hipoglicemia persistente em recém-nascidos e crianças com alto risco de dano neurológico irreversível. Apesar dos recentes progressos realizados pela base genética da genética molecular, o diagnóstico ainda é frequentemente realizado tarde demais, dada a heterogeneidade dessa doença. Relatamos o caso duma paciente que varia de hipoglicemia secundária e de difícil controle a hiperinsulinemia congênita. Seu teste genético mostrou mutação no gene ABCC8.