ЗНАЧЕНИЕ АНТИТЕЛ К 21-ГИДРОКСИЛАЗЕ ДЛЯ ДИАГНОСТИКИ, ДИФФЕРЕНЦИАЛЬНОЙ ДИАГНОСТИКИ И ПРОГНОЗИРОВАНИЯ АУТОИММУННОЙ ПЕРВИЧНОЙ ХРОНИЧЕСКОЙ НАДПОЧЕЧНИКОВОЙ НЕДОСТАТОЧНОСТИ

Abstract

21-hydroxylase (21-OH) is the main antigen of the adrenal cortex, so the determination of antibodies (Ab) to 21-OH can help in the diagnosis and prognosis of chronic primary adrenal insufficiency (CPAI). Purpose of the study: evaluation of the relevance of Ab to 21-OH for the diagnosis and prediction of autoimmune CPAI. Materials and methods of research: the study consisted of three blocks: 1) assessment of the specificity and sensitivity, as well as the prognostic potential of Ab to 21-OH in patients with polyglandular autoimmune syndrome (APS) – individuals with APS type 1 with and without CPAI (n=106); 2) assessment of the dynamics of the level of Ab to 21-OH – patients with autoimmune CPAI were included (n=41); 3) assessment of the significance of Ab data for the differential diagnosis of various forms of CPAI, including patients with CPAI and APS type 1 exclusion (n=30). The study of Ab to 21-hydroxylase was performed using enzymelinked immunosorbent assay (BioVendor kits, Czech Republic). Results: statistically significant differences were obtained in the frequency of detection of Ab to 21-OH in patients with or without PCNI (p<0,001). The sensitivity of the method was 96%, specificity was 75%, a positive predictive value was 90%, and the negative predictive value was 89%. In 83% of patients, the level of Ab decreased with time (median size decreases – 20,4%/year). An inverse relationship was also found between the level of Ab and the duration of the course of CPAI (R=–0,460, p<0,001). In a group of 30 patients with CPAI and with exclusion of APS type 1, 21 were found to have Ab to 21-OH, only one of them had a monogenic non-autoimmune cause of CPAI (a mutation in the MC2R gene). Monogenic forms of CPAI were found in another 7 patients (mutations were found in the DAX1 and ABCD1 genes), among them an increase in Ab to 21-OH was not detected. Conclusion: determination of Ab to 21-OH is a specific and sensitive method for the diagnosis of autoimmune CPAI. An increase in Ab to 21-OH is a risk marker of autoimmune CPAI development.