International Journal of Biochemistry Research & Review

Introduction: COVID-19 is caused by SARS-CoV-2 and primarily affects the respiratory tract. Zinc, as an immunomodulatory micronutrient, was considered for reducing disease severity and mortality in patients with COVID-19. Serum ferritin, an acute-phase reactant, is an important marker of immune dysregulation. C-reactive protein (CRP) is an acute-phase protein that participates in complement activation. Adenosine and adenosine deaminase (ADA) have roles in immune and inflammatory processes, while lactate is involved in immune-cell metabolism and is regulated through lactate dehydrogenase (LDH). The study therefore assessed the roles of zinc, ferritin, CRP, ADA, and LDH in immune and inflammatory processes associated with COVID-19.

Materials and Methods: The study included 214 patients with COVID-19, who were classified into three groups according to serum zinc concentration: Group I, ≤ 40 µg/dL; Group II, 41–150 µg/dL; and Group III, ≥ 150 µg/dL. Disease severity was assessed using peripheral oxygen saturation (SpO2), and the relationships among serum zinc, ferritin, CRP, ADA, and LDH were evaluated.

Results: Serum ferritin and CRP levels were significantly higher in patients with elevated serum zinc concentrations. ADA levels were also higher in patients with elevated serum zinc levels, although the difference was not statistically significant. Serum LDH levels did not differ significantly among the zinc groups, although LDH was elevated across the groups. Patients with compromised oxygen saturation had significantly higher CRP, serum ferritin, and ADA levels, indicating greater systemic inflammation in the hypoxic group. Circulating zinc levels did not differ according to oxygenation status, and no significant overall correlation was observed between circulating zinc and the acute inflammatory markers.

Discussion: The findings indicate that systemic inflammation and cellular injury in COVID-19 were reflected by coordinated elevations in inflammatory and tissue-injury biomarkers, particularly serum ferritin, LDH, and ADA. These results support the value of assessing multiple inflammatory biomarkers when characterising disease severity. In contrast, baseline circulating zinc concentrations varied independently of the observed inflammatory changes and did not demonstrate robust standalone utility for severity stratification. Although adequate zinc status remains important for normal immune function, isolated serum zinc measurement should be interpreted cautiously and in conjunction with clinical findings and broader inflammatory-marker profiles.