Pathobiological alterations affecting the distinct clinical courses of pediatric versus adult COVID-19 syndrome.

Background/aim: The clinical presentation of pediatric coronavirus disease 2019 (COVID-19) is associated with a milder disease course than the adult COVID-19 syndrome. The disease course of COVID-19 has three clinicobiological phases: initiation, propagation, and complication. This study aimed to assess the pathobiological alterations affecting the distinct clinical courses of COVID-19 in pediatric age groups versus the adult population. We hypothesized that critical biogenomic marker expressions drive the mild clinical presentations of pediatric COVID-19.

Materials And Methods: Blood samples were obtained from 72 patients with COVID-19 hospitalized at Ankara City Hospital between March and July 2021. Peripheral blood mononuclear cells were isolated using Ficoll-Paque and density-gradient sedimentation. The groups were compared using a t-test and limma analyses. Mean standardized gene expression levels were used to hierarchically cluster genes employing Euclidean Gene Cluster 3.0. The expression levels of identified genes were determined using reverse transcription-polymerase chain reaction.

Results: This study found that gene expression was significantly downregulated in the pediatric group (p < 0.05, FC: 1.57) and gene expression was significantly upregulated in the adult group (p < 0.05, FC: 2.98). The study results indicated that the expression of critical biogenomic markers, such as the first-phase ( and ) and second-phase ( and ) receptor genes, was crucial in the genesis of mild clinical presentations of pediatric COVID-19. gene expression was lower in pediatric COVID-19.

Conclusion: The interrelationship between the and genes may prevent the progression of COVID-19 from initiation to the propagating phase in pediatric patients. High gene expression could potentially contribute to a protective effect and may be a contributing factor for the mild clinical course observed in pediatric patients.