Significance of CD49f in diagnosis of minimal residual disease in pediatric acute leukemia.

Minimal residual disease (MRD) is the most important prognostic indicator in acute lymphoblastic leukemia (ALL) in childhood. Multiparametric flow cytometry (FCM) is a technique that is often used to determine MRD, and many markers have been identified. Another marker examined in the MRD analysis is CD49f. We aimed to determine the importance of CD49f expression in MRD detection. Immunophenotyping MRD and CD49f expressions were performed in patients with Pre-B cell ALL at the diagnosis, and on the day 15. 27 patients were included (F/M: 10/17). The mean age was 6.6±4.8 years. 6 (22.2%) patients were in the standard risk group, 14 (51.9%) patients were in the intermediate risk group, and 7 (25.9%) patients were in the high-risk group. MRD was detected in 15 (55.6%) patients. Cytomorphological remission was observed in 21 (77.7%) patients on the 15th day. 10 of these patients (66.6%) were MRD positive. CD49f levels at diagnosis and at 15th day were mean 38.4 ± 22.1 and 5.4±12.6, respectively. A significant decrease in CD49f expression was observed at follow up (p=0.00). Mean CD49f levels in MRD positive and MRD negative patients were 7.8±17 and 2.8±2 at day 15, respectively (p=0.64). There was no correlation between MRD and CD49f at day 15 (p=0.54). We observed that leukemic blasts express CD49f at a high rate, and this expression continues to decrease on the 15th day. We concluded that studies including more patients are required to assess the performance and importance of CD49f as an indicator in MRD. [ABSTRACT FROM AUTHOR]