The association between Tumor Necrosis Factor-alpha level (TNF-α) and moderate COVID-19 patients in Egypt

: Background: Infection with viral agents causes upregulation of cytokines such as Tumor Necrosis Factor-alpha (TNF-α), which is considered an important mediator of inflammation. TNF-α has been associated with a poor prognosis in patients with the severe acute respiratory syndrome (SARS). Patients and methods: This study included 66 mild COVID-19 patients with confirmed COVID-19 infection and 22 healthy people as a control group, these study subjects were randomly selected irrespective of the age group and both genders were included, 1 ml blood sample was collected for performing serum TNF-α levels test, Reagents of EIAab is located at East Lake Hi-Tech Development Zone, Wuhan China. Human tumor necrosis factor ELISA kit TNF-α serum levels immunoassay test catalog number E0133h. Results: This study reveals that serum TNF-α levels for mild COVID-19 patients and healthy control people were non-significant with a p-value of 0.1191 between the two groups. Conclusion: the serum TNF-α level is not a significant biomarker for diagnosis or prognosis of mild COVID-19 patients (Outpatients and patients under home observation), while other studies reported patients with COVID-19 demonstrated significantly elevated levels of TNF- 𝛼 upon admission to hospitals.

In this study, the levels of TNF-α, were measured through ELISA in sera from healthy volunteers as a control group, and patients with moderate COVID-19, Outpatients, and patients under home observation are included in this study, while hospitalized patients are not included, this study aims to investigate the association between TNF-α serum levels and mild COVID-19 infection.

Study population Patients
This study included 66 non-hospitalized patients with confirmed COVID-19 infection, and 22 healthy people as a control group, these study subjects were randomly selected irrespective of the age group and both genders were included. It was performed following the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All the studied population was informed about the purpose of sample collection and patients were free to refuse sample collection.

Data collection
In this cross-sectional study, we obtained data regarding 66 non-hospitalized patients with confirmed COVID-19 via real-time reverse transcriptionpolymerase chain reaction (PCR), and 22 healthy people as a control group, they came to Alyameny laboratory in Alexandria, Egypt for biomarkers and complete blood count investigations, we reviewed the medical records and compiled data between August 12 and December 30, 2020.

Assay procedure as manufactory instructions:
Wuhan EIAab science Co for reagents is located at East Lake Hi-Tech Development Zone, Wuhan China. Human tumor necrosis factor ELISA kit TNFα serum levels immunoassay test catalog number E0133h and samples allowed to be at room temperature before testing, (serum was separated from a blood sample by centrifugation).

Discussion:
TNF-is a pleiotropic inflammatory mediator produced by several cells of the immune system to regulate a wide variety of immune responses (14) , TNFis made of 157 nonglycosylated amino acids following proteolytic cleavage of the membrane-bound form, which is made of 233 amino acids (15) , Of significant importance is the relation between TNFand the current COVID-19 situation (16) . TNF-plays a central role in mediating the cytokine response required to initiate and potentiate the inflammatory response in the lungs (17) , which leads to increased accumulation of pulmonary inflammatory fluid and vascular permeability (18) .
The expression of TNF-is increased during lung injury, where it provokes a variety of biological responses to modulate the anomaly by inducing the expression of numerous other inflammatory mediators, which is a key step consisting of stimulating multiple genes involved in protective processes (19) . It was noticed that patients with COVID-19 demonstrated significantly elevated levels of TNF-upon admission to hospitals (20) , this study was conducted on  (32) In severe COVID-19 infection, TNF-α is produced in excess, causing an increase in the systemic inflammatory response that results in tissue damage.
One of the functions of TNF-α is to increase the recruitment of phagocytic cells and increase the autolysis reaction of cells (33) . TNF-α is associated with acute lung injury and predicts prognosis (32) .

Conflict of interest
There are no conflicts of interest.

Financial support and sponsorship
This research did not receive any specific grant from funding agencies in the public, commercial, or not-forprofit sectors.