Análise da expressão de CD105 (endoglina) em precursores linfoides normais e em blastos neoplásicos de pacientes pediátricos com leucemia linfoblástica aguda de células precursoras b no estado da Bahia

Abstract

Acute lymphocytic leukemia (ALL) has a bimodal incidence, characterized by loss of normal ability to differentiate and proliferate, with an accumulation of lymphoid progenitor cells and clonal expansion in bone marrow, peripheral blood, and other tissues. It is the most common in childhood and adolescence, with several factors associated with its etiology. The use of flow cytometry, in conjunction with morphological analysis, is essential for the diagnosis and follow up of such diseases. In this context, the analysis of the expression of molecules in the maturation curve of normal and neoplastic lymphoid precursors is a tool that contributes to elucidating the behavior of the medullary environment in the analysis of Measurable Residual Disease (MRD). The endoglin molecule (ENG, CD105) is a co-receptor of the TGF-β family that plays a crucial role in the regulation of angiogenesis. Although best known for its expression in endothelial cells, endoglin is also expressed in hematopoietic stem cells (HSC) and has recently been suggested as a marker of poor prognosis for pediatric patients with B Cell Precursor ALL (BCP-ALL). In this context, the present work evaluated the expression of CD105 in normal precursors of B cells, also called hematogonia, and in leukemic blasts from pediatric patients with BCP-ALL. The study was carried out on onco-pediatric patients samples from Hospital Aristides Maltez, Martagão Gesteira, and Santa Casa de Itabuna, using pre-defined panels for the analysis of CD105 expression. Events were acquired using a BD FACSCalibur flow cytometer and analyzes were performed using the Infinicyt™ 9 1.8 software. Patient samples, evaluated at diagnosis or during MRD, were individually analyzed for the presence or absence of antigenic expression of each marker used in flow cytometry. CD105, at diagnosis, was expressed in 73.33% of IX patients with BCP-ALL, with the highest expression in leukemic blasts. When compared with MRD, the highest expression was in hematogonia in negative MRD (67.28%), with a mean MFI of 87.26. When analyzed individually (patient 1), the blasts had a higher expression and MFI, 21.56 and 26.14, respectively. CD105 can be considered a potential prognostic marker for the detection of response to induction therapy in childhood BCP-ALL, and may serve to optimize treatment decisions.