Immune response in children with COVID‐19 is characterized by lower levels of T‐cell activation than infected adults

Abstract

Study of immunological features of immune response in 14 children (aged from 12 days up to 15 years) and of 10 adults who developed COVID‐19 show increased number of activated CD4 and CD8 cells expressing DR and higher plasmatic levels of IL‐12 and IL‐1β in adults with COVID‐19, but not in children. In addition, plasmatic levels of CCL5/RANTES are higher in children and adults with COVID‐19, while CXCL9/MIG was only increased in adults. Higher number of activated T cells and expression of IL‐12 and CXCL9 suggest prominent Th1 polarization of immune response against SARS‐CoV2 in infected adults as compared with children.

Heightened Circulating Interferon-Inducible Chemokines, and Activated Pro-Cytolytic Th1-Cell Phenotype Features Covid-19 Aggravation in the Second Week of Illness

“…The behavior of other pro-inflammatory cytokines in Covid-19 has proven more erratic across the literature, with discordant findings being published (6,22,23). In particular, the failure to detect differences in IL-1b and TNF-a might reflect receptor antagonism or differential cytokine concentrations in diseased tissue and peripheral blood (24).…”

“…Having ascertained a pattern of "cytokine storm" (6,22,(25)(26)(27), more evident in patients with severe disease, and given the crucial interplay between innate and adaptive immunity, we next investigated T-cell responses, aiming to shed light on the contribution of adaptive immunity on Covid-19 course.…”

“…Accordingly, in our patient cohort, despite similar demographic and pre-existing comorbidities, as well as analogous lung damage, we show reduced neutrophil and increased lymphocyte counts in moderately versus severely ill individuals at an average of 7 days from symptom onset. Because lymphocyte activation/exhaustion has been suggested in Covid-19 adult patients (3,22), we next characterized T-cell immunophenotype and function according to disease severity, with particular focus on SARS-Cov-2-specific response.…”

Genome-Wide Asymptomatic B-Cell, CD4+and CD8+T-Cell Epitopes, that are Highly Conserved Between Human and Animal Coronaviruses, Identified from SARS-CoV-2 as Immune Targets for Pre-Emptive Pan-Coronavirus Vaccines

“…Nevertheless, since ''common cold'' Coronaviruses are usual in children, it will be interesting to determine whether children who appeared more resistant to COVID-19 compared to adults will have robust antiviral memory T cell responses to some asymptomatic epitopes. A stronger CD4 + and CD8 + T cell responses to common Coronavirus epitopes in children would shed some light on the unique situation currently seen in COVID-19 where immune children tend to be more resistant to SARS-CoV-2 infection and disease, as compared to adults 84,85 . Such a Towards A Multi-Epitopes Pre-Emptive Pan-Coronavirus Human Vaccine result would also imply that a pan-Coronavirus vaccine incorporating cross-reactive highly conserved SARS-CoV-2 human CD4 + and CD8 + T cell epitopes in the next pan-Coronavirus vaccine would boost protective T cell immunity that is previously induced by a ''common cold'' Coronavirus, thus protecting not only from seasonal circulating ''common cold'' Coronaviruses, but also from SARS-CoV-2 infection and disease.…”

BCG vaccine may generate cross-reactive T cells against SARS-CoV-2: In silico analyses and a hypothesis

“…Given the severity of the disease, vaccines and therapeutics for SARS-CoV-2 are urgently needed [1] . Accumulating evidence suggests that the human CD4+ and CD8+ T cells can response to SARS-CoV-2 [4] , [5] , [6] , [7] , however, the knowledge about immune reactions against SARS-CoV-2 in human body is still partial [1] .…”