Patients
Our study was conducted in the Infectious Diseases and Chest Diseases Clinic of our hospital between May 2020 and July 2020. For this study, three groups; namely, the mild/moderate COVID-19 group, severe COVID-19 group, and control group, were formed. Patients with symptoms of fever, muscle/joint pain, cough, and sore throat with a respiratory rate of <30/minute and a partial pressure of oxygen (SpO2) level on room air of >90% were regarded as mild/moderate cases (1). In contrast, cases with tachypnea (respiratory rate > 30/min), with an SpO2 level < 90%, with bilateral diffuse pneumonia on chest X-ray or tomography, or those that developed acute organ dysfunction, ARDS and/or sepsis, and/or septic shock were considered as severe cases. From the 32 patients who were hospitalized with a clinical presentation of COVID-19 and a positive real-time reverse transcription polymerase chain reaction test, a 5-cc sample of blood was collected on their first day of hospitalization and at the first month of their follow-up. The blood samples were centrifuged at 4000 rpm for 10 minutes to obtain the serum and maintained at −80°C until analysis.