Immunological Markers in Patients with Gastroenterological Manifestations During Different Periods of COVID-19

Abstract

Materials and Methods. A retrospective study of 785 medical records of patients hospitalized between 05.2020 and 12.2020 with a diagnosis of moderate to severe new coronavirus COVID-19 infection was performed in phase I. The study was conducted. The primary objective was to evaluate clinical symptoms with a focus on detecting gastroenterologic manifestations of COVID-19. After discharge from the Covid hospital in 3, 6 and 12 months, a telephone questionnaire was conducted using a specially developed questionnaire by the staff of the Department of Internal Medicine of the FSBEU VO BSMU of the Ministry of Health of the Russian Federation to identify gastroenterological symptoms, as well as using the standard questionnaire for the assessment of gastrointestinal symptoms GSRS (Gastrointestinal Symptom Rating Scale) and the Bristol Stool Assessment Scale. 247 respondents took part in the survey, after which they were divided into 3 groups according to the criterion of presence and duration of gastrointestinal symptoms. Group 1 — patients with persisting gastrointestinal symptoms in the period from 4 to 12 weeks (ongoing symptomatic COVID) — 30 people; Group 2 — patients with duration of gastrointestinal symptoms more than 12 weeks (post-COVID syndrome) — 75 people. The control group (group 3) consisted of 151 patients who had survived COVID-19 without the development of postcoviral syndrome. At stage II, serum concentrations of immunologic markers (interleukins 4, 6, 8, 18; rheumatoid factor, antibodies to DNA,) were studied in each group of patients.Results. There was a statistically significant increase in the mean age in group 1 and group 2 patients (p=0.02*10-4 and p=0.01*10-9), as well as in the duration of hospitalization in group 1 patients compared to the control group (p=0.04). Women predominated in both groups 1 (p=0.01) and 2 (p=0.002). The time of outpatient treatment before hospitalization averaged 8.1 days. In both groups of patients there was a statistically significant increase in IL-18 level (p=0,095; p=0,88*10-9), in group 2 there was an increase in rheumatoid factor level (p=0,044) in comparison with the control group. A statistically significant increase in IL-6 levels was also revealed in both studied groups in comparison with the control group (p=0,020; p=0,000017), while the mean values were within the reference intervals.Conclusions. Thus, patients who have had moderate to severe COVID-19 are susceptible to the development of post-Covid syndrome, including gastroenterological manifestations. For the first time, an elevated level of IL-18 was detected in this category of patients, which can serve as both a diagnostic marker and a potential target for targeted therapy.