الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 209 |  |  |
| | | from | 209 | | |
Abstract
Coronaviruses are known for their role in respiratory tract infections. There are seven types of human coronavirus including 229E, NL63, OC43 and HKU1, MERS-CoV, SARS-CoV-1 and SARS-CoV-2.
Coronaviruses have been the focus of many studies since the emergence of deadly strains including SARS-CoV-1, MERS-CoV and recently SARS-CoV-2 that caused a pandemic. However, there are still many unresolved questions regarding the pathogenesis of SARS-CoV-2 and especially the reasons underlying the extremely different clinical course, ranging from asymptomatic forms to severe manifestations.
This study aimed to correlate the peripheral lymphocyte subsets alterations by flowcytometry and IL6 serum level with disease severity in COVID 19 patients.
An observational cross-sectional study was performed at Ain Shams University isolation hospitals, Cairo, Egypt during the period from July 2020 to September 2020. Forty five (45) participants were enrolled in this study including 30 COVID-19 patients and 15 healthy controls. There were 21 (70.0%) male patients and 9 (30%) female patients. The patients’ group was divided into two groups; moderate and severe. Moderate patients’ group included 15 moderate COVID-19 patients with mean of age (50.87 ± 19.2 SD) years. They were 10 males and 5 females. Severe patients’ group comprised 15 severe COVID-19 patients; they were 11 males and 4 females with a mean of age (66.4 ± 12.3SD) years.
EDTA anti-coagulated blood samples were collected for all study participants. For the patients’ group, samples were collected at day 1 of admission and before receiving any treatment. Levels of lymphocyte subsets (CD3+CD4+ T helper cells, CD3+CD8+ T cytotoxic cells, CD19+ B cell and CD3-CD56+ NK cells) were analyzed by flowcytometry in whole blood. Serum samples were also tested for IL-6 level using ELISA technique.
Older age with a male predominance (70%) was more prone to severe COVID-19 infection; about 73.33% were above 60 years old.
80% of COVID 19 patients showed absolute lymphopenia and the severe patients’ group showed lower absolute lymphocytic count than that in moderate patients’ group. CD3+CD4+ and CD3+CD8+ T cells and CD3-CD56+ NK cells counts reduced significantly in patients’ group compared to the healthy controls (p-value <0.01) and this reduction was more prominent in severe patients’ group. However, the CD19+ B cell counts did not vary significantly neither between control and patients’ group nor between moderate and severe patients’ subgroups.
ROC curve analysis was performed to assess the diagnostic value of different lymphocyte subsets in differentiation severe from moderate COVID-19 patients; Our results showed that the count of CD3+CD4+, CD3+CD8+ T cells and CD3- CD56+ NK cells is a significant predictor of COVID-19 severity with the AUC were 0.884, 0.773 and 0.753 respectively in severe patients with COVID-19 pneumonia, while CD19+ B cell count had no significant relation with disease severity (P-Value = 0.138).
As a result of the highest AUC for the CD3+CD4+ cells count, CD3+CD4+ T helper cell count is considered the most important factor in differentiation severe from moderate COVID-19 patients at a cut off value (≤ 264 cells/ µL) with high specificity 100% and sensitivity 66.67% followed by CD3+CD8+ T cell count with a cutoff value (≤ 195 cells/ µL) with high specificity 93.33% and sensitivity 66.67%. Our findings may shed light on affection of cell mediated immunity with COVID-19 severity. This can be early warning of high risk of developing severe COVID-19 and help early intervention and treatment.
Serum concentrations of IL-6 were elevated in patients’ group than in control group and were significantly higher in severe patients than in moderate patients. ROC curve could effectively discriminate between moderate and severe patients’ group at a cut-off value >60 pg/ml associated with 80% sensitivity, 86.7% specificity and AUC=0.842.