Elevation of Normal B Cells in Children with ALL Can Predict Relapse.

Flow cytomerty analysis of bone marrow (BM) is performed routinely in children with acute leukemia in different phases of chemotherapy. The aim of flow cytometric monitoring is to measure the amount of residual blasts and to evaluate the efficacy of chemotherapy. Multiparametric flow cytometry may be also used to evaluate normal hematopoisis in BM of patients with acute leukemia in different phases of chemotherapy. The aim of this study was to study normal lymphopoiesis in patients with relapsed disease. Twenty-two pediatric patients with ALL were enrolled in the protocol of study. Patients were treated in accordance with BFM-98 protocol. Eighteen children were in complete remission during follow-up period, while 4 children relapsed. Three of the relapsed children had B-lineage ALL, and one had T-cell ALL. Using multiparamertic flow cytometry we measured normal pro-B cells (CD19+CD34+), immature B (CD19+CD10+CD20+ and CD19+CD10−CD20+) and mature B (CD19+CD10−CD20+) cells in BM of relapsed patients in different phases of chemotherapy. Amounts or different subsets of B cells were compared with reference values determined in patients with relapse-free disease. Reference values were expressed as mean ± confidence interval for each subset of B cells and for each phase of chemotherapy. Elevation of immature normal B-cells was determined in all 4 patients who relapsed.Three during chemotherapy. Increased amount of mature B cells was determined 3 mo before the diagnosis of relapse in the patient who relapsed after the end of chemotherapy.This event was not observed in patient who did not relapse We conclude that elevation of normal immature B cells in BM of patient with ALL can be a predictive marker for eventual relapse.