Estudo fenotípico da maturação da linha eritróide na medula óssea

Abstract

Erythropoiesis is a complex process of differentiation of erythroid progenitors into red blood cells that occurs in the bone marrow of humans during childhood and adulthood. This process, regulated by several factors, allows the differentiation of erythroid progenitors, not morphologically identifiable, into erythroid precursors (proerythroblasts, basophilic erythroblasts, polychromatic erythroblasts, orthochromatic erythroblasts), these into reticulocytes and finally, into red blood cells, that are small, anucleated, uniform and biconcave cells highly specialized in oxygen transport. In clinical laboratories, the morphology analysis and differential counts are of great importance for the study of the erythroid differentiation. In this study we have studied the maturation of the erythroid lineage by flow cytometry, by staining bone marrow samples with a combination of eight monoclonal antibodies with different specificities, conjugated with different fluorochromes (anti-CD36 FITC, anti-CD105 PE, anti-CD34 PerCP-Cy5.5, anti-CD117 PE-Cy7, anti-CD33 APC, anti-CD71 APC-H7 / APC-Alexa Fluor 750, anti-HLA-DR PB and anti-CD45 PO) and compared the results with those obtained by morphology. Flow cytometry allowed the identification of four stages of red cell maturation with different phenotypic profiles. In stage 1, more immature, erythroid cells expressed all the antigens analyzed, in stage 2 they lose CD45, CD34, HLA-DR and CD33, followed by CD117 in stage 3 and CD105 in stage 4. CD71 and CD36 expression persist till the end of the erythroid maturation, reaching the maximum in stages 3 and 4, respectively. The stage 1 probably correspond to proerytroblasts (although some preproerytoblasts may also be included), stage 2 to basophilic erythroblasts, stage 3 to polychromatic erythroblasts and stage 4 to orthochromatic erythroblast. In summary, using an eight-color staining, we characterized the red cell maturation by flow cytometry and established a relationship with the phenotypically identifiable stages with those traditionally identified by morphology.

Date of Award	2012
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Margarida Lima (Supervisor) & Maria Luís Queiroz (Co-Supervisor)