FACTORS ASSOCIATED WITH VARIABILITY IN IL-6 LEVELS IN PATIENTS WITH COVID-19

Abstract

SUMMARY. An increase in the systemic level of IL-6 in patients with COVID-19 is considered as a relevant parameter for predicting the most severe course of the disease and the need for intensive therapy. We conducted a study of the level of interleukin-6 in 77 patients with coronavirus disease aged from 29 to 87 years (mean age 59.3±12.4 years), among whom there were men – 43 (55.8 %), women – 34 (44.2 %). The examination was carried out the next day after hospitalization. On average, the period from the onset of the disease was (9.2±3.5) days. According to the results of the study, it was established that the average level of IL-6 among patients with COVID-19 significantly exceeded the similar indicator in relatively healthy individuals: Me – 5.30 (3.57; 11.32) pg/l against 2.68 (2,22; 2.97) (p<0.001).

Analysis of IL-6 content depending on demographic, clinical and general laboratory characteristics showed that its increase in blood serum correlates with age (rs=0.251, p=0.030), and the highest average level of this cytokine was observed in the age group of 70–79 years (rs=0.381, p=0.001). among the clinical characteristics, the correlation of the level of IL-6 with the severe course of the disease was determined (rs=0.381, p=0.001), which corresponds to the role of this cytokine as a possible marker of the progression of the severe course of the disease. Accordingly, there is also a tendency to link the fatal outcome of the disease with an increase in the level of IL-6 (rs=0.210, p=0.071), which may have a reliable result with a larger number of observations. Among the general laboratory indicators, a direct correlation was observed between the level of IL-6 and the ESR value (rs=0.271, p=0.019), the number of bands (rs=0.301, p=0.009), residual nitrogen (rs=0.231, p=0.047), the content of CRP (rs=0.241, p=0.037), which, like IL-6, is an important marker of the acute phase of inflammation, and high levels of this protein in the early stage of coronavirus disease are positively correlated with the degree of lung damage and the severity of the disease. Thus, as a result of the conducted study, it was established that the increase in the level of interleukin-6, which is observed in patients with COVID-19 is correlated with the severity of the disease and may also be related to age (especially the age group of 70–79 years) and a number of concomitant pathology and clinical conditions, among which coronary heart disease, obesity, fever, increased BP (systolic), decreased saturation are especially important. Higher levels of interleukin-6 are observed with an increase in the content of C-reactive protein, residual nitrogen, ESR, and the number of bands.