CLONE OF PAROXYSMAL NOCTURNAL HAEMOGLOBINURIA AND OTHER PREDICTORS OF THE RESPONSE TO IMMUNOSUPPRESSIVE THERAPY IN PATIENTS WITH IDIOPATHIC APLASTIC ANAEMIA

Introduction. The pathogenesis of acquired aplastic anaemia (AA) is based on immune-mediated development of bone marrow failure. The absence of clear reasons for the development of immune aggression determines the relevance of investigations aimed at studying genetic disorders in the remaining pool of hematopoietic stem cells, in the hematopoietic niche, as well as mechanisms underlying the failure of immunological tolerance. Aim. The present literature review describes the most relevant markers used for characterising AA patients on the basis of their possible response to immunosuppressive therapy (IT) and for forming groups being at risk of developing refractoriness and clonal evolution. General findings. The overall survival probability in patients with AA following program IT is comparable to the results of transplanting allogeneic hematopoietic blood stem cells (allo-HSCT) from a related donor in the first line of therapy. According to current Russian and international recommendations, the tactics for treating AA patients is determined by the patient's age and the presence of an HLA-identical sibling. Allo-HSCT from a related HLA-identical donor is a method used for treating patients younger than 40 years; however, the possibility of performing allo-HSCT is limited by donor availability. Although the event-free survival probability during IT is inferior to the results of allo-HSCT, IT remains the main treatment method for most patients with AA. In order to minimise adverse outcomes, it is necessary to consider predictors of treatment efficacy along with the likelihood of developing late clonal evolution as early as at the AA diagnosis stage. Patient evaluation and formation of risk groups will facilitate selection of the most optimal treatment approach at the therapy planning stage, which includes either IT combination with thrombopoietin receptor agonists, or a search for an unrelated HLA-compatible donor and timely allo-HSCT.