2.1. Patients and healthy controls
For primary screening, the total number of 120 cases, including 97 COVID-19 patients and 23 healthy controls, were recruited in this study. Healthy control samples were collected from the Blood Transfusion Organization of Iran 5 months before the COVID-19 epidemic in Iran and stored at -20 °C. All patients were laboratory-confirmed positive for SARS-CoV-2 by real time PCR using throat or nasopharyngeal swab specimens. Patients’ sera were collected during routine clinical testing and incubated at 56 °C for 30 minutes to inactivate viruses and then stored at -20 °C until use. The mean age and standard deviation of patients and controls were 58.6±15.8 and 50.5±5.1, respectively. The patients group included 63 male and 34 female subjects, and the healthy control group included 18 males and 5 female individuals. All patients were admitted to Imam Khomeini hospital affiliated to Tehran University of Medical Sciences. Physical examination and pulse oximetry were performed for all patients, and chest CT scanning was performed for suspicious cases. Patients with the following criteria were admitted; 1) saturation of oxygen (SpO2) level <93% without supplementary oxygen and 2) characteristics of COVID-19 disease on the patient’s CT scan, i.e., involvement of more than half of the lungs. Also, patients with comorbidities and severe symptoms or signs of COVID-19 on their CT scan with normal SpO2 levels were admitted. Major clinical manifestations observed in patients include fever, cough, dyspnea, and low blood oxygen saturation levels. Serum samples were collected from all patients 3-7 days after hospital admission.
Patients were classified into severe and non-severe groups. Severe illness included patients who had SpO2 <60% or required intensive care unit (ICU) or received invasive (mechanical) ventilation. Altogether, 49 patients (50.5%) were classified as severe, and 48 patients (49.5%) were non-severe.
Subsequently, 66 of 97 screened patients with the highest levels of NP and RBD-specific antibodies were selected for Pepscan analysis. The mean age and standard deviation of the selected patients were 59.6±15.1. They included 44 male and 22 female patients which 45 (68.2%) were in severe condition of disease and 21 (31.8%) were non-severe.
This study was approved by the Ethical Committee of the National Institute for Medical Research Development (NIMAD) of Iran (IR.NIMAD.REC.1399.194). Written consent was obtained from all patients included in this study or their legal representatives.