Elevated CD56brightNK cell and IFNγ levels in the blood of children with common cold provides a clue for preventing COVID-19

Abstract

Abstract Objective: We aim to detect and compare the levels of natural killer (NK) cells (CD56bright and CD56dim), interleukin (IL)18, interferon (IFN)α, and IFNγ in the blood of children with common colds and healthy children, in order to provide clues for the prevention of coronavirus disease 2019（COVID-19）at the current stage. Study design: A total of 153 children, including 49 with common colds and 104 healthy children, were recruited for this cross-sectional study. The demographic characteristics and lifestyle habits of healthy children and children with common cold are similar. Peripheral venous blood samples were collected by professional nurses for flow cytometry analysis and cytokine determination. Results: We found that compared to healthy children, children with common colds had significantly reduced forced vital capacity (FVC), and increased CD56brightNK cell ratio, and levels of serum IL18 and IFNγ (all P < 0.05). Linear regression analysis showed that the increase in IFNγ level was positively correlated with the increase in CD56brightNK cell, IFNα, and IL18 levels (all P < 0.05). The increase in CD56brightNK cell ratio was positively correlated with the increase in IFNγ and IL18 levels (all P < 0.05). Conclusions: Children may resist common cold by increasing the levels of CD56brightNK cells, IFNγ, and IL18 in their blood, which could be the reason why children are more susceptible to common cold but exhibit stronger immunity against COVID-19. CD56brightNK cells may serve as a crucial breakthrough in addressing the current prevalence and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants.