IMMUNOPATHOGENETIC AND CLINICAL ASPECTS OF ANTIBODY FORMATION TO CATALASE IN SYSTEMIC LUPUS ERYTHEMATOSUS

Objective. Study of the clinical and pathogenetic role of anti-catalase antibodies in systemic lupus erythematosus (SLE) using a technology involving antigen immobilization on magnetic polyacrylamide beads. Materials and methods. The study included 56 patients with SLE aged over 18 years who were receiving inpatient treatment in rheumatology department; the diagnosis of SLE was verified according to the 2019 EULAR/ACR criteria. SLE disease activity was assessed using the SLEDAI-2K scale. The SLICC/ACR DI index was used to quantify accumulated organ damage. The control group consisted of 30 apparently healthy individuals. Catalase activity in blood serum was measured spectrophotometrically using ammonium molybdate. The level of IgG antibodies against catalase (AKA) in blood serum was determined using an enzyme-linked immunosorbent assay (ELISA) in a proprietary modification. Results. It has been established that catalase activity levels in patients with SLE were significantly lower than in healthy individuals. An inverse correlation was found between enzyme activity and ACA levels in patients with this disease. It was shown that the highest ACA levels are observed in cases of SLE with high disease activity. ACA concentrations upon hospital admission differed significantly between SLE patients with skin or CNS involvement and those without such involvement. To study biomarker dynamics during treatment, the SLE group was divided into two subgroups: patients who underwent intensification of immunosuppressive therapy during hospitalization (66.1%) and patients on a stable treatment regimen (33.9%). The mean change in SLE disease activity in the dose-escalation subgroup was -5.05 ± 0.72 SLEDAI-2K points, whereas in the stable-therapy subgroup, it was -0.14 ± 0.33 SLEDAI-2K points. In the dose-escalation subgroup, a statistically significant inverse correlation was observed between the change in SLE disease activity and the change in catalase activity, as well as a weaker positive correlation between the former parameter and the change in ACA concentration.Conclusion. Our findings indicate a significant role for catalase in the pathogenesis of SLE and point to the potential for developing innovative biomarkers—based on catalase and ACA activity—that reflect the efficacy of therapy for this disease.