Correlation of vitamin D levels with serum parameters in Covid-19 patients.

BACKGROUND: It is well-established that vitamins have many beneficial roles and protect humans against inflammatory diseases. Vitamin D, a lipid-soluble vitamin, plays a crucial role in viral infections. Therefore, this study aimed to investigate if serum 25(OH)D levels affect morbidity, mortality, and levels of inflammatory parameters in COVID-19 patients. METHODS: 140 COVID-19 patients participated in this study (65 outpatients and 75 inpatients). Their blood samples were collected to determine TNFα, IL-6, D-dimer, zinc, Ca2+, and 25(OH)D levels. Patients with O2 saturation <93% were admitted and hospitalized in the infectious disease ward (inpatient group). Patients with O2 saturation >93% received routine treatment and were discharged (Outpatient group). RESULTS: The serum levels of 25(OH)D in the inpatient group were significantly lower than those in the outpatient group (p < 0.001). Serum TNF-α, IL-6, and D-dimer levels in the inpatient group were significantly higher than those in the outpatient group (p < 0.001). Serum TNF-α, IL-6, and D-dimer levels were inversely correlated with 25(OH)D levels. No significant differences were observed in the serum levels of zinc and Ca2+ between the studied groups (p = 0.96, p = 0.41 respectively). Ten out of 75 patients in the inpatient group were admitted to ICU (intubated). Nine out of them lost their lives (the mortality rate in ICU-admitted patients was 90%). CONCLUSIONS: The lower mortality and severity of COVID-19 patients with higher 25(OH)D levels represented that this vitamin alleviates the severity of COVID-19.

Leukemia Inhibitory Factor Suppresses NKG2D mRNA Expression and Presentation on Human Natural Killer Cells.

Leukemia inhibitory factor (LIF) is a multi-functional cytokine secreted from cells such as lymphocytes and hepatocytes. This study aimed to evaluate the effect of LIF on natural killer group 2 member D (NKG2D) receptors' expression and presentation on natural killer (NK) cells.  For this purpose, peripheral blood mononuclear cells taken from 4 young male healthy blood donors were isolated and the effect of LIF (25 ng/mL) after 12, 24, and 48 hours of incubation, on NKG2D receptors expression and presentation was investigated using flow cytometry and real-time-polymerase chain reaction (PCR). All of the steps of the experiment were performed in duplicate. After periods of 12, 24, and 48 hours, LIF reduced both the expression and presentation of the NKG2D receptor on NK cells. The results suggest that this cytokine has a direct modulating activity on the body's immune response through suppression of NKG2D receptor expression and presentation on NK cells.