Autoreactive processes in children in the initial period of multisystem inflammatory syndrome associated with SARS-CoV-2 and after rehabilitation

BACKGROUND: The problem of the pathogenesis of the multisystem inflammatory syndrome (MIS-C), associated with SARS-CoV-2, remains relevant, but is still far from being resolved. In this regard.

AIM: The aim our research was to study and evaluate the levels of autoantibodies to native and denatured DNA in the blood serum of children who underwent MIS-C, associated with SARS-CoV-2, in comparison with the initial period of the pathological process.

MATERIALS AND METHODS: 101 children aged 2 to 17 years old were examined, 77 of them was with a confirmed diagnosis of MIS-C associated with SARS-CoV-2. We have formed 3 groups: group 1 — children with MIS-C upon admission to the hospital; group 2 — children who underwent MIS-C after a course of rehabilitation; group 3 — comparison group. All children underwent determination of the concentrations of IgG-autoantibodies to native and denatured DNA in blood serum, which was performed by EIA ELISA using commercial test systems of Vector-Best LLC (Russia) according to the manufacturer’s instructions. Statistical processing of the obtained results was carried out using the Statistica v. 10.0 application package. Statistical processing used the Newman–Keuls multiple comparison test.

RESULTS: It was noted that both in the initial period of MIS-C and after rehabilitation, an increased content of autoantibodies to nDNA and dDNA was determined compared to the control group. At the same time, there was a significant excess of the levels of indicators in the post-rehabilitation period compared with the initial period of MIS-C. During a clinical examination of children who underwent MIS-C, most of them noted the appearance of pain in the joints. The results obtained indicate the persistence of inflammatory reactions with the development of an autoreactive component. This requires both the search for risk markers for the development of MIS-C and further monitoring of children who have undergone MIS-C to prevent autoimmune complications, including arthritis, damage to the vascular endothelium with the possible formation of thrombotic complications.

CONCLUSIONS: In the acute period of MIS-C and after rehabilitation, increased levels of the average content of autoantibodies to nDNA and dDNA were noted compared to the control. Individual values of autoantibodies to nDNA and dDNA exceeded normative levels of the indicator were found in a significantly larger number of children in the post-rehabilitation period after MIS-C, and this excess was more pronounced compared to the acute period of the process. When assessing the clinical condition of children after MIS-C, most of them showed pain in the joints during exercise, abdominal and neurological disorders, and decreased tolerance to physical activity, which indicates persistent inflammatory reactions.