PB1712 PROGNOSTIC IMPACT OF ABERRANT EXPRESSION IN ACUTE MYELOID LEUKEMIA

Abstract

Background:Immunophenotyping allows identification of aberrant antigen expression in acute myeloid leukemia (AML). These antigens are related with particular and genetic abnormalities and recognized as factors of poor prognosis in AML.Aims:To assess prognostic impact of aberrant expression in treated AML.Methods:Our study is retrospective (January 2017‐June 2018) concerning 97 cases of AML (AML 3 and mixed phenotype acute leukemia were excluded) of the adult from 18 to 60 years old diagnosed and treated at one institution. The immunophenotyping was performed by flow cytometry (BD Facs Canto II®) after incubation with monoclonal antibodies labeled with different flurochromes. Aberrant expression correspond to the expression of antigens of the lymphoid line B or T in AML. We studied the impact of aberrant expression on complete remission (CR) and relapse in a delay of 1 year. We excluded the cases with missing data.Results:We had collected 33 cases of treated AML. Aberrant lymphoid antigen were seen in 18 cases (54.54%). It is about CD 56 in 6 cases (33%), CD7 in 6 cases (33%), CD4 in one case (5.5%) and CD19 in 2 cases (11%). Association between lymphoid B and T antigens or T and NK antigens was seen in 3 cases (CD19 + CD7, n= 1; CD7 + CD56, n=2). We didn’t find any correlation between expression of lymphoid antigen and lower CR rates (93% vs 54%; r= 0.17, p = 0.42). Analysed individually, no lymphoid antigen was associated with more induction failure. Relapse seems to be associated with aberrancy expression without statistically significant association (p = 0.29); CD7 was the most aberrant antigen expressed in cases of relapses (75%).Summary/Conclusion:The expression of aberrant antigens in AML is correlated with poor prognosis in literature. This result was not statistically prouved in our study and that's can be explained by the reduced size of our sample. Otherwise, our study shows the pejorative impact of the expression of CD7 on cases of relapses. Expression of CD56 (33% of our cases), similar to literature (10‐30% of cases), was not associated with higer relapse's rate in the limit of our sample (12.5% of AML CD56 + ).Despite the limited number of cases, this study allow us to better understand the impact of aberrant antigens expression in prognosis of AML. A study on a larger series is underway.