CD117-CD15 in acute myeloid leukemia: no role as LAIP in the study of minimal residual disease. To the Editor: Leukemia-associated immunophenotypes ...
doi:10.1111/ejh.12042
European Journal of Haematology 90 (171–174)
LETTER TO THE EDITOR
CD117-CD15 in acute myeloid leukemia: no role as LAIP in the study of minimal residual disease
To the Editor: Leukemia-associated immunophenotypes (LAIPs) are widely used to assess minimal residual disease (MRD) in acute myeloid leukemia (AML) because they are absent or rare in healthy bone marrow (BM) but reported in more than 90% of AML (1, 2). The asynchronous expression of CD117 marker (either CD34+ or CD34-) with later CD15 is the most frequent LAIP identified with an incidence that ranges from 40% to 50% of AML and represents a good prognostic factor (3). The majority of published works did not report cells coexpressing CD117 and CD15 in BM of healthy subjects (4–6), and this combination of antigens was proposed as a marker of MRD in AML. However, CD15 was found in a small proportion of CD34-positive cells (7). We quantified CD117+/CD15+ BM cells in 14 healthy control subjects and 48 AML patients in complete remission (CR) whose 30 displayed at presentation 1%, the coexpression was assumed to be aberrant. Fresh BM samples from 69 patients were obtained at diagnosis between May 2010 and April 2012 from Haematology Department of IRCCS ‘Casa Sollievo della Sofferenza’ Hospital (Italy). Diagnosis of patients was based on morphology, immunophenotyping, cytogenetics, and molecular biology. Among the 69 patients diagnosed as AML, 58 (84%) received chemotherapy and 50 (86%) of them achieved CR. Two patients died after induction; hence, 48 patients maintained CR after chemotherapy and were evaluated in this study. Samples were collected after the cessation of chemotherapy (at least 1 month after the last course and prior of autologous or allogeneic stem cell transplantation), thus the analysis was not influenced by different times of hematological recovery and support therapies used. Patients were treated according to protocols of EORTC/GIMEMA AML-12 (AIDA- 0493 for acute promyelocitic leukemia) or according to the regimen FLAG-Myocet on the basis of the age minor or major than 60 years old, respectively. CR was achieved when patients showed
