Cluster of Differentiation 45: An Adjunct to Flowcytometric Diagnosis of Leukemias

Background: This Cross sectional comparative study was performed to compare the mean fluorescence intensity of cluster of differentiation 45 between healthy individuals and patients with acute lymphoblastic leukemia. Patients and methods: Thirty three healthy individuals (mean age 11 years) and 41 patients with B cell acute lymphoblastic leukemia (mean age 7 years) were enrolled in the study in department of Immunology, Armed Forces Institute of Pathology, Rawalpindi, from Jan 2009 to April 2011, after ethics committee approval and obtaining informed consent. For immunophenotyping analysis, blood was stained with monoclonal antibodies using lyse wash procedure. For each subject, panel for staining consisted of cluster of differentiation 3, cluster of differentiation 5, cluster of differentiation 7, cluster of differentiation 10, cluster of differentiation 19, cluster of differentiation 20, , cluster of differentiation 13, cluster of differentiation 34, cluster of differentiation 1314, cluster of differentiation 1333, cluster of differentiation 45, HLA-DR, and intracytoplasmic myeloperoxidase as well as terminal deoxynucleotidyl transferase . Cells were then analyzed on Becton Dickinson FACSCalibur flow cytometer using Cell Quest Pro software. For each subject, mean fluorescence intensity was calculated in software along with geometric mean and standard deviation. Results: Mean of geometric means of cluster of differentiation 45 expression on blasts of patient population was considerably low (145) as compared to lymphocytes of healthy population (764), being statistically significant (p<0.0001). Conclusion: cluster of differentiation 45 is useful in differentiating mature lymphocytes from blasts in ALL cases. Keywords: Flow cytometry, acute lymphoblastic leukemia, cluster of differentiation 45, mean fluorescence intensity.