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 ANPEP gene expression was significantly downregulated in the pediatric group (p < 0.05, FC: 1.57) and IGF2R 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 (ACE2 and ANPEP) and second-phase (EGFR and IGF2R) receptor genes, was crucial in the genesis of mild clinical presentations of pediatric COVID-19. ANPEP gene expression was lower in pediatric COVID-19. Conclusion: The interrelationship between the ANPEP and ACE2 genes may prevent the progression of COVID-19 from initiation to the propagating phase in pediatric patients. High IGF2R gene expression could potentially contribute to a protective effect and may be a contributing factor for the mild clinical course observed in pediatric patients.

Current community transmission and future perspectives on the COVID-19 process

Background/aim: COVID-19 syndrome due to the SARS-CoV-2 virus is a currently challenging situation ongoing worldwide. Since the current pandemic of the SARS-CoV-2 virus is a great concern for everybody in the World, the frequently asked question is how and when the COVID-19 process will be concluded. The aim of this paper is to propose hypotheses in order to answer this essential question. As recently demonstrated, SARS-CoV-2 RNAs can be reverse-transcribed and integrated into the human genome. Our main hypothesis is that the ultimate aim of the SARS-CoV-2 virus is the incorporation to human genome and being an element of the intestinal virobiota. Materials and methods: We propose that the SARS-CoV-2 genomic incorporation to be a part of human virobiota is essentially based on three pathobiological phases which are called as the 'induction', 'consolidation', and 'maintenance phases'. The phase of 'recurrence' complicates any of these three disease phases based on the viral load, exposure time, and more contagious strains and/or mutants. We have performed the 'random walk model' in order to predict the community transmission kinetics of the virus. Results: Chimerism-mediated immunotherapy at the individual and community level with the help of vaccination seems to be the only option for ending the COVID-19 process. After the integration of SARS-CoV-2 virus into the human genome via the induction, consolidation, and maintenance phases as an element of intestinal virobiota, the chimerism would be concluded. The 'viral load', the 'genomic strain of the SARS-CoV-2', and 'host immune reaction against the SARS-CoV-2' are the hallmarks of this long journey. Conclusion: Elucidation of the functional viral dynamics will be helpful for disease management at the individual- and community- based long-term management strategies.