Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 14 1 2020 01 01 27 37 Wafaa El- Neanaey Department of Clinical and Chemical Pathology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt Rania Swelem Department of Clinical and Chemical Pathology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt Omar Ghallab Department of Internal Medicine (Hematology), Faculty of Medicine, University of Alexandria, Alexandria, Egypt Sara Abu-Shelou Department of Clinical and Chemical Pathology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt 2019 05 14 2019 09 02 Background: The present work aimed to investigate the expression of CD160/ CD200 in CLL and other mature B-cell neoplasms (MBN) and their use as an additional diagnostic tool for differentiating CLL from other MBN. Materials and Methods: Using flowcytometry, we detected the expression of CD160 &CD200 on B-cells from 30 CLL patients, 30 other MBN patients in addition to 20 controls. CDs160/200 measurements were determined as a percentage expression (≥20% was considered positive) and as a ratio of the mean fluorescence intensities (MFIR) of leukemic cells/controls and were considered positive when the ratios were ≥2 and 20, respectively. Results: 90% and 100% of the CLL group expressed CDs160/200 in comparison to 60% and 63.3% of other MBN (p=0.007, p<0.001) respectively. By MFIR; 96.7% and 50% of our CLL group expressed CDs160/200 in comparison to 76.7% and 30% of other MBN, respectively. CDs160/ 200 were not expressed on the controls. Positive co-expression of CD160 and CD200 was found in 90% of the CLL cases, 60% of HCL patients & only in 40% of B-NHL. However, double negative expression of both markers was found only in 24% of the B-NHL patients. Conclusion: CD160 with CD200 can be used as additional diagnostic markers to the available routine panel to differentiate between B-CLL & other non-specified B-NHL patients.   https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/1131 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/1131/809