Abstract

Background: Acute promyelocytic leukemia (APL) is an aggressive subtype of acute myeloid leukemia (AML) that requires rapid diagnosis and early intervention. Previous studies spotted light on APL being negative for members of β2 integrin family CD11a and CD18. The aim of this work: was to study the value of absence of CD11a and CD18 molecules in screening and its relation to prognosis of APL cases. Patients and methods: This cross sectional study was conducted on seventy adult (>18 years) patients with de novo AML, recruited from National Cancer Institute, Cairo University. They were divided in to 2 groups; group 1 of APL cases (n= 35) and group 2 of AML-Non APL cases (n= 35) as a comparative group. Both groups were investigated by flow cytometry for the expression of CD11a and CD18 molecules on leukemic cells. Results: Comparison between group 1 and group 2 illustrated significant reduction in % of cells expressing CD11a (p= 0.014), CD18 (p=0.008) and % of cells co-expressing CD11a /CD18 (p=0.007) in group 1 compared to group 2. There was significant positive correlation between % of cells expressing CD18 and TLC (r=0.411, p=0.014). There was significant positive correlation between CD11a MFI and hepatomegaly (r=0.390, p=0.021) in AML-Non APL group. Regarding the output data of ROC curve for discriminative percentage of leukemic cells expressing CD11a and CD18 between APL and Non-APL groups, at cut off 78.95% and 23.5% respectively, the specificity for both was 60% and 68.6%, respectively. While sensitivity was 77.1% and 68.6%, respectively, with Area Under Curve (AUC) of 0.671 and 0.686 and p value of 0.014, and 0.008 for leukemic cells expressing CD11a and CD18, respectively. Conclusion: [1] There is significant reduction in % of cells expressing CD11a and CD18 in APL patients, but they were neither sensitive nor specific to be used as single markers in diagnosis of APL patients. [2] Positive correlation seen between the most important prognostic factor, TLC and both CD18 MFI and percentage of cells expressing CD18 could throw light on the potentiality of CD18 as a prognostic factor. [3] Significant positive correlation between CD11a MFI and hepatomegaly in Non-APL cases might suggest a role of CD11a in migration of leukemic cells.

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