Retrospective Immunophenotypic Profile of Acute Leukemias in the State of Rio Grande Do Norte, Northeast, Brazil
Authors: Bahia Ian Antunes Ferreira , Paiva Aldair de , Oliveira Gustavo Henrique de Medeiros , Silva Giovani Arlindo , Theodoro Flavia Cristine Medeiros , Paiva Hugo Diogenes De Oliveira , Martins Robson Eduardo , Freitas Rodrigo Villar , Silveira Ivanaldo Amâncio da , Cabral-Marques Otavio , Luchessi Andre Ducati , Rosa Neta Antonia Pereira , Cavalcanti Junior Geraldo Barroso 
Published: December 2023

INTRODUCTION:The main acute leukemias (ALs) are lymphoid (B or T lineage ALL) and myeloid (AML), in addition to biphenotype AL (BAL) and undifferentiated ALL (IAL), which are rarer. This variation reflects on therapy, requiring methods to characterize these leukemias. Thus, methods such as immunophenotyping by flow cytometry (ICF), multiparametric and quantitative, help in the follow-up of these neoplasms. Objective: The aim of this study was to demonstrate the immunophenotypic diagnostic profiles in patients with AL in Rio Grande do Norte, state, Brazil by FC. Methodology: Bone marrow and peripheral blood samples from 371 patients clinically diagnosed with AL were investigated by CF, using a panel of monoclonal antibodies for the detection of lymphoid (B, T and NK) and myeloid antigens, as well as markers related to cell immaturity such as CD34, Terminal deoxynucleotidyl Transferase (TdT).At the same time, information related to clinical data, age group and sex of patients was also collected. Results: Of all LA investigates 71 were B cell-ALL, 55 T cell-ALL, 239 AML, 04 BAL and 02 IAL. Regarding the immunophenotypic pattern, the main subgroups in relation to age group and were evidenced through the FC. 06/71 were Pro-B ALL, 48/71 Common ALL, 06/71 cyt mü chain ALL and 11/71 mature sIgM+ B-ALL. In B-cell lineage ALL, 51 (71.8%) of the cases were children (less than or equal to 18 years old) and 20 (28.2%) adults (over 18 years old). In T-cell ALL, 9 (16.4%) were pre-T ALL, 12 (21.8%) intermediate ALL and 29 (52.7%) medullary T-type ALL, corresponding to a total of 36.4% children and 63.6% adults. In AML, there was a predominance of involvement in adult patients, corresponding to47 (80.7%) of cases and 192 (80.3%) in children. Biphenotypic and undifferentiated AL were detected in adult patients. DISCUSSION: The B cell-ALL were characterized by natural arrest of B-cells precursors based on the expression of antigens related to this lineage in: i) Pro-B ALL (CD19+, HLA-Dr+, CD34+, TdT+); ii) Common ALL (CD10+, CD19+, cCD79a+, cytCD22+, HLA-Dr+, TdT+/- and CD34+/-); iii) cyt mü chain+ ALL (cyt IgM+, CD19+, HLA-Dr+, cytCD79a+, cytCD22+, CD10-, CD34-) and iv) mature B-ALL (sIgM+, sCD22+, CD10+/-, CD20+ and kappa+ or lambda+). The T-ALL were classified into: i) pre-T-ALL (CD7+, cytCD3+, HLADr+, CD34+ and TdT+), ii) intermediate T-ALL (CD1a+, CD2+, CD7+, cytCD3+, TdT+ and HLADr+, CD4+/CD8+) and Medullary T-ALL (CD4+ or CD8+, sCD3+, CD1a-, TdT+, HLADr+/- and CD34-). It was also possible to observe the aberrant expression of myeloid antigens in B and T-ALL, such as CD13, CD33 and CD66b, mainly related to ALL in the context of KMT2A rearrangement with lineage switching. In addition to transferrin receptors (CD71) and IL-2 receptor (CD25), which have been reported in the context of ALL BCR+/ABL+, as well as the presence of the Philadelphia chromosome. In AMLs, the most observed subtypes were those with little differentiation and with a monocyte component. (CD64+/CD14+). CD15+/CD34+ expression was also observed, indicative of asynchrony of maturation, and phenotypic aberrancy of lymphoid antigens in some cases, predominantly CD7. In addition to other antigens such as CD2 and CD19, CD19 and CD56, In addition, ALL was more frequent in children and males, while AML in adults and females in general, with a predominant incidence in males among adult patient. Conclusion: When properly applied, ICF can have a great impact on the diagnosis, classification and prognostic analysis of neoplastic processes.