Avaliação dos níveis de expressão do gene PD-L1 em pacientes portadores de Síndrome Mielodisplásica

Abstract

Myelodysplastic Syndrome (MDS) is composed of a group of clonal hematopoietic diseases that present great heterogeneity, being characterized by defects in hematopoietic progenitor cells and by immune and epigenetic dysregulation. Its carriers have clinical and pathological manifestations such as anemia, cytopenias and dysplasia. The immune checkpoint acts in the regulation of the immune system's response, preventing the immune system from attacking its own tissue. However, some cancers are able to use this mechanism to bypass the immune system, in a process of immune evasion. The aim of this study is to analyze the PD-L1 gene expression, which is part of the immunological checkpoint and is involved in the immune evasion process in patients with MDS, associating the findings with cytogenetic alterations, clinical and laboratory variables of prognostic impact. Samples were obtained from the bone marrow of 67 MDS patients and four controls. For analysis of gene expression and cytogenetics, real-time polymerase chain reaction (RT-qPCR) and bone marrow karyotype examination with short-term G-Band culture were performed. Patients with MDS aged over 80 years had decreased expression of the PD-L1 gene compared to those aged 60 years or less (p=0.005) and those aged between 60 and 70 years (p=0.044). In addition, in this cohort, the PD-L1 gene was more expressed in individuals with two cytogenetic alterations, when compared to a cytogenetic alteration (p=0.004), and in normal karyotype patients compared to a cytogenetic alteration (p=0.003) . The findings in this study go against the trend found in the literature, however, PD-L1 is important for MDS due to its role in the immune evasion process.