Expressão da L-Selectina e do CD44 nas leucemias linfóides agudas em crianças e adolescentes

• Ano de defesa: 2009
• Autor(a) principal: Sousa, Daniel Willian Lustosa de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Leucemia-Linfoma Linfoblástico de Células Precursoras; Adolescente; Criança; Antígenos CD44
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/6886

Introduction – Altered expression or function of adhesion molecules on leukemic blasts may contribute to the evolution of acute leukemia and its biological behavior. The elevated expression of adhesion molecules in ALL might be correlated with the extramedullary dissemination of blast cells, CNS involvement and leukemia tumor burden. Purpose – To analyze the expression of L-selectin and CD44 in ALL in children and adolescents. As well as to evaluate the prognostic factors (age, gender, initial leukocyte count, immunophenotype, FAB and EGIL classification, DNA index and early response to treatment) and the extramedullary presentation of ALL, to finally correlate the prognostic factors with these adhesion molecules. Patients and Methods – From November 2007 to November 2008, 76 patients with newly diagnosed ALL started on Brazilian GBTLI-ALL Protocol. The diagnosis was based on cytological, immunophenotypic, and cytogenetic methods. The mean fluorescence intensity (MFI) and the percentage of the adhesion molecules blasts cells was measured by flow cytometry using triple staining with McAb directly conjugated. CD45-PerCP positive cells were gated for blasts analysis. Anti-CD44-PE (Clone HP2/9 - Immunostep®) and CD62L-FITC (Clone HI62L - Immunostep®) were used to mark the adhesion molecules. The Cell Quest program was used for data acquisition and analysis. Statistical analysis was done by SPSS 16.0 Software. The association of features, prognosis and response to treatment was assessed by Chi-square, Fisher exact and Mann-Whitney tests. Overall survival curves were constructed by the Kaplan-Meier method and the log-rank test. Multivariate Cox regression analysis showed independent prognostic factors. Results – The mean age at diagnosis was 6.3±0.5 years (range 9mo to 17yr) and 65% of them were boys. Clinical findings were hepatomegaly (63%), splenomegaly (58%), lymphadenopathy (44%). CNS involvement was detected in 6.6% of cases and mediastinal mass appeared in 11.8% of them. Patients were classified into low risk (54%) and high risk (46%). FAB classification identified 83% as L1 and 17% as L2. Immunophenotypically, 89.5% of patients were classified as B-lineage ALL and 10.5% as T-lineage ALL. The most frequent EGIL subtype was B common and pre-B-ALL (51.5% and 45.5%, respectively). DNA index greater than 1.16 was found in 19% of the patients and was associated with favorable prognosis. On the D8 evaluation, 95% of the patients had blast count lower than 1.000/mm3 and leukocyte count lower than 5.000/mm3. The remission induction rate was 95% and there was a rate of 2.6% of death during induction therapy. CD44 had greater expression to the rate of 87.5% in T-cell ALL (MFI=150.44±20.29) with no statistical correlation. A significant positive correlation was demonstrated between 84% of CD44 expression and Leukemia burden tumor cases (p=0.01; OR=4.8). There was statistical correlation between L-selectin expression (87.5%/MFI=272.33±52.72) and T-cell ALL (p=0,004). No significant correlation was detected between L-selectin and CD44 expression and other prognostic factors. Multivariate statistical analysis (adjusted for overall survival) indicated that initial leukocyte count, gender, T immunophenotype and L-selectin were independent factors. Conclusion – L-selectin and CD44 expressions were elevated in ALL studied, mainly in T-cell ALL. The research demonstrated that there is an association between CD44 expression and leukemia tumor burden, which might be involved in the dissemination of leukemic cells and the progression of the disease.