Association between the copper/selenium ratio and the immune response to SARS-CoV-2 infection

Aim: To assess the association serum levels of selenium (Se) and copper (Cu) with symptoms and IgG immune response to SARS-CoV-2. Patients & methods/materials: Blood samples and nasopharyngeal swabs were obtained from 126 COVID-19 patients with mild and severe symptoms. The serum levels of Cu and Se were measured by atomic-absorption spectrophotometry. Results & conclusion: Mean Se was higher in patients with mild symptoms and IgG nonresponders, whereas mean Cu was higher in patients with severe symptoms and IgG responders. The Cu/Se ratio was lower in patients with no IgG responses to infection and mild symptoms versus IgG responders with severe symptoms. These results suggest the Cu/Se ratio as a nutritional biomarker of severity and IgG immune response in COVID-19 patients.The association between the strong immune response to infections and trace elements such as copper (Cu) and selenium (Se) is well documented. Se and Cu are changed under infectious conditions. Since SARS-CoV-2 causes inflammation in the body, this study was conducted to evaluate the association between serum levels of Se and Cu changes with the symptoms and immune response to SARS-CoV-2, and then assess the Cu/Se ratio. Blood samples and nasopharyngeal swabs were obtained from 126 SARS-CoV-2 participants with mild and severe clinical symptoms. The SARS-CoV-2 infection and immune response to the virus were confirmed in the laboratory. Next, the Se and Cu serum levels were measured. Finally, we analyzed our findings. The median Se levels were higher in patients with mild symptoms (115 μg/l) in comparison with the severe symptoms group (99 μg/l), and the mean Se levels were higher in immune nonresponders (110.33 ± 3.38 μg/l) in comparison with the immune responders' group (102.42 ± 1.83 μg/l). However, the median Cu was higher in participants with severe symptoms (124 μg/dl) compared with the mild symptoms group (103 μg/dl), and the mean Cu levels were higher in immune responders (112 ± 9.98 μg/dl) in comparison with the immune nonresponders' group (105.1 ± 9.4 μg/dl). The Cu/Se ratio was lower (ratio <1) in participants with no responses to infection and mild symptoms versus responders with severe symptoms. Our results suggest that the Cu/Se ratio may act as a nutritional biomarker of severity and immune response in SARS-CoV-2-infected patients.