الفهرس 
COVID-19 IN CHILDRENOnly 14 pages are availabe for public view
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Abstract
C
OVID-19 is a respiratory disease caused by the Severe acute respiratory syndrome related to corona virus 2 (SARS COV-2). Regulatory T cells (Tregs) are an essential component of the adaptive immune system which may play an important role in the regulation of immune responses to COVID-19. This study aimed to investigate the frequency of CD4+CD25+FOXP3+ Tregs in patients with SARS COV-2, including those with multisystem inflammatory syndrome in children (MIS–C), in comparison to healthy control children. The relationship between the number of these cells and both the disease severity and SARS COV-2 inflammatory markers was studied.
SARS COV-2 patients comprised 12 males and 8 females. Their ages ranged between 6 months and 15 years (mean ± SD = 6.28±5.35 years). The control group comprised 20 apparently healthy children. They included 11 males and 9 females. Their ages ranged between 6 months and 16 years (mean ± SD =6.25 ±5.21years).
Six patients had COVID-19 infection and the other 14 patients suffered from MIS-C. According to the degree of the disease severity, 8 patients had moderate disease and 12 patients had severe disease, and the latter were admitted at Pediatric Intensive Care Unit. Regarding the outcome of the disease, 17 patients recovered and 3 patients died.
According to the radiological classification of COVID-19 infection by using COVID-19 Reporting and Data System (CO-RADS), five patients had CO-RADS 4, four patients had CO-RADS 5 and One patient had CO-RADS 6 who had MIS-C.
Decreased frequency of Tregs was found in only 10% of patients with SARS COV-2. On the other hand, increased frequency of Tregs was found in 30% of patients with SARS COV-2. According to the pediatric normal reference range for age, elevated CRP and D-Dimer values were found in 85% and 90% respectively of these patients. Lymphopenia, neutropenia, neutrophilia, thrombocytopenia and elevated levels of ALT, ferritin and LDH were found in 30%, 10%, 60%, 30%, 20%, 45% and 70%, respectively of all patients with SARS COV-2.
Although all patients with SARS COV-2, patients with COVID-19 and patients with MIS–C had higher frequency of Tregs than healthy control children, this elevation was not significant (P=0.068, P=0.062 and P= 0.20, respectively).
Patients with MIS–C had significantly higher values of ALT, LDH and D-dimer than patients with COVID-19. On the other hand, patients with severe SARS COV-2 had significantly higher values of D-dimer than patients with moderate SARS COV-2. There was a significant negative correlation between the frequency of Tregs and the neutrophilic count in all patients with SARS COV-2.
In contrast, there were non-significant correlations between the frequency of Tregs and the other studied parameters in all patients with SARS COV-2.