Role of CD200 in differentiating chronic lymphocytic leukaemia from mantle cell lymphoma and comparing its expression across various B cell chronic lymphoproliferative disorders

Abstract

Multiparameter flow cytometry is a useful tool for the diagnostic evaluation of chronic lymphoproliferative disorder recently, it has been shown that CD200 may improve the distinction between chronic lymphocytic leukemia and mantle cell lymphoma, but the role of CD200 expression in atypical chronic lymphocytic leukemia and other chronic lymphoproliferative disorder remains to be established. Methods: A total of 200 samples were evaluated by Flow cytometry over a period of 2 years from august 2017 to October 2019. Cases were diagnosed according to WHO classification of tumours of hematopoietic and lymphoid tissues, 2017. Results: CD200 was strongly expressed in chronic lymphocytic leukemia and was revealed to be an excellent marker to distinguish chronic lymphocytic leukemia from mantle cell lymphoma, even in cases of atypical chronic lymphocytic leukemia. However, lack of CD200 was not an exclusive finding of mantle cell lymphoma, being also observed in other chronic lymphoproliferative disorder. Conclusion: CD200 was expressed by all cases of chronic lymphocytic leukemia as well as atypical chronic lymphocytic leukemia cases while it is negative in MCL thus it is particularly useful in distinguishing chronic lymphocytic leukemia/small lymphocytic lymphoma from other CD5+ B-cell neoplasms. CD200 is also expressed in most of the cases of hairy cell leukemia, splenic marginal zone lymphoma, and follicular lymphoma. CD200 is a useful addition to Moreau et al. panel for analysis of B cells in lymphoid tissue in Bone Marrow aspirates, and Peripheral Blood.