Inflammatory biomarkers in patients with COVID-19

The new coronavirus, termed severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), is causing the coronavirus disease 2019 (COVID-19), which is a complex multisystem disease that in its severe form is manifested by severe pneumonia and damage to the blood vessels, heart, liver, and kidneys. Clinical data suggest that a high percentage of the patients with COVID-19 develop an abnormal inflammatory response, which can progress to multiorgan failure and death. This study aims to analyze the values of inflammatory biomarkers C-reactive protein (CRP) and interleukin 6 (IL-6), together with white blood cell (WBC) count, erythrocyte sedimentation rate (Se), ferritin (FER), and serum iron (IRN) in patients with COVID-19 who develop clinical presentations that differ in severity, and to assess the clinical significance of these parameters for diagnosis and prognosis of the course of the disease. This study was designed as a retrospective observational study. The study included a total of 115 patients divided in two groups: Group A- asymptomatic and mild cases of COVID-19, N=55 (36 men and 19 women; mean age 53.3 ± 1.4 y.) and Group B- moderate and severe cases of COVID-19 patients in need of hospitalization, N=60 (38 men and 22 women; mean age 56.1 ± 1.3 y.). All patients had a positive PCR test for SARS‑CoV‑2. The study was conducted in the period September – December 2020. Statistical analysis of the data showed that the two groups of patients did not differ in age. Mean values of Se, WBC, CRP, IL-6, and FER were higher in Group B patients than in Group A. Very high statistical significance was observed for CRP and IL-6 (p<0.001), while high statistical significance was observed for Se and FER (p<0.01). The mean value of WBC was higher in Group B patients, but with borderline statistical significance (р=0.051). The mean value of IRN was significantly lower in Group B patients compared with Group A (p<0.05). We observed a statistically significant positive correlation between CRP and IL-6 in both groups of patients [0.525, р<0.01 in Group A vs. 0.259, р<0.05 in Group B]. Serum iron shows a significant inverse correlation with CRP and IL-6, but only in Group A patients [CRP (-0.380), IL-6 (-0.424); р