Analysis of serum cytokine and protective vitamin D levels in severe cases of COVID-19 

The data from this study provides evidence that vitamin D may have an anti‐inflammatory effect on COVID‐19 patients and vitamin D may provide protective effects.

• Serum cytokine concentrations in COVID-19 patients were significantly higher than in controls.  
• Vitamin D levels were significantly lower in patients with COVID-19 (6.82 ± 3.29 ng/dl) than compared to the control group (21.96 ± 5.39 ng/dl) 
• There was a negative correlation between vitamin D levels and proinflammatory cytokines (IL-1 = -0.513; IL-6 = -0.473; TNF-a = -0.545) 

A total of 74 participants were included; The patient’s group contained 31 (19 females and 12 males) cases with severe COVID‐19 and 43 individuals (16 females and 27 males) without a history of serious illness as a control group. 

• COVID-19 patients were vitamin D deficient while controls were insufficient.  
• Low vitamin D levels may be due to increased melanin, malabsorption, obesity, and abstinence of the sun. 
• Decreased vitamin D levels may lead to decreased NK cell activity. 

COVID‐19 virus induces cytokine production. It induces pro‐ inflammatory responses, proliferates efficiently from the human respiratory tract, those infected with viruses increase pro‐inflammatory cytokine and chemokine production within 24 h. Levels of all viruses tested were measured and high cytokines were found, especially IL‐6, TNF‐α levels were found to be significantly higher. Our data in Table 1 shows that the virus enables uptake and cytokine storm production. High levels of cytokine storm syndrome’ may be one of the critical hallmarks of COVID‐19 disease severity. There is ample evidence that vitamin D is essential for normal immune and lung functions to fight pathogens and prevent autoimmune diseases. It is demonstrated that there exists the potential of vitamin D supplementation to prevent acute respiratory infection by modulating the innate immune response. As vitamin D therapy can reduce the COVID‐19 diseaseburden, so daily supplementation is preferred to better outcomes in COVID‐19 patients. Preventing vitamin D deficiency in patients with severe COVID‐19 seems prudent as vitamin D deficiency is very common and it is associated with both an increased risk of various inflammatory diseases and increased susceptibility to infections including COVID‐19. 

• Patients were divided into two groups. Patients in the COVID‐19 group (n = 31) and individuals without a history of serious illness or infection were used as the control group (n = 43). The serum concentrations of interleukin‐1 (IL‐1), IL‐6, IL‐10, IL‐21, and tumor necrosis factor‐α (TNF‐α) were measured by enzyme‐linked immunosorbent assays. Levels of serum vitamin D were detected with Liquid chromatography–mass spectrometry methodologies. TNF‐α, IL‐1, IL‐6, IL‐10, IL‐21, and vitamin D levels were measured in all patients. 

Bayraktar N, Turan H, Bayraktar M, Ozturk A, Erdoğdu H. Analysis of serum cytokine and protective vitamin D levels in severe cases of COVID-19. J Med Virol. 2022 Jan;94(1):154-160. doi: 10.1002/jmv.27294. Epub 2021 Aug 30. PMID: 34427934; PMCID: PMC8661791.