Variation of CD20 expression in B Acute Lymphoblastic Leukemias in pediatric patients and its impact on treatment

Abstract

Introduction: Immunophenotyping by flow cytometry is useful to assign lineage to pathological cells in B acute lymphoblastic leukemia (B-ALL). Monitoring of the therapeutic response on day 15 is based on the quantification of blasts by flow cytometry. The expression of cellular antigens, such as CD20, allows the possible use of immunotherapies in B-ALL patients. Objectives: To assess the effect of corticosteroids on the expression of CD20 surface antigen in B-ALL patients at diagnosis and on day 15 of the induction phase. Materials and methods: The immunophenotypic study by multiparametric flow cytometry was reanalyzed in 78 pediatric patients at diagnosis and on day 15. The expression of CD20 values w ere recorded both in blasts and normal B lymphocytes. A descriptive statistical approach was used and the comparisons were made using the Student’s t test for normal distributions and the Mann-Whitney test as a non-parametric method. Results: In 78% of the patients, an increase in the percentage of expresión in CD20 was observed in the blast cells present on day 15 compared to diagnosis. Besides, 37% of the patients changed their status from negative to positive for CD20 on day 15. Conclusions: The expression of CD20 on day 15 of the treatment in patients with B-ALL was increased versus its value at the moment of diagnosis and could thus become candidates for immunotherapy.