Interest of the CD148, CD180 and CD200 Combination in Flow Cytometry Analyses for Mature B-Cell Neoplasms Diagnosis

Abstract

There are a number of small B-cell proliferations that do not fall into any of the types of B-cell neoplasms recognized in the WHO classification using classical immunophenotypic markers. This situation is notably encountered in the case of the differential diagnosis of marginal zone lymphoma (MZL), atypical chronic lymphocytic leukemia (aCLL) mantle cell lymphoma (MCL) or lymphoplasmacytic lymphoma (LPL). This is mostly due to the lack of immunological specific markers especially when histological samples are not available or during leukemic phases of atypical B-cell neoplasms. In order to find new markers to discriminate between these different malignancies, we have previously developed a proteomic strategy based on the analyses of plasma membrane microparticles and proposed two new specific markers: CD148 and CD1801, 2 for MCL and MZL respectively. The simultaneous use of these two markers, together with the CD200 that is positive in most cases of CLL and negative in MCL3 could be of great interest to better assess the differential diagnosis.In the present study, we report the results obtained by the combination of the three markers studied in addition to the routine flow cytometry panel: CD148 (Clone 143-41 FITC); CD180 (Clone G28.8 PE) and CD200 (Clone OX104 APC). An expression profile of these proteins have been established on a well characterized set of patients: CLL with a Matutes score > 3 (N=28); MCL harboring t(11;14) translocation or CCND1 overexpression (N=20); LPL (N=16) classified following cytological morphology, IgM peak and positivity of CD38, and MZL (N=27), displaying a CD5- CD23-immunophenotype associated to a splenomegaly. For each group the mean of fluorescence intensity and Standard Error have been determined.MCL patients exhibited a strong expression of CD148 (MFI = 1480) combined with a weak expression of CD180 and CD200 (MFI = 888 and 426 respectively). A weak expression of CD148 and CD180 (MFI = 495 and 754) coupled to a strong expression of CD200 (MFI = 3750) was typical of the CLL group and a weak expression of CD148 and CD200 (MFI = 640 and 1200) coupled to a strong expression of CD180 (MFI = 5300) was observed in the MZL group. A moderate expression of these three markers was observed in the LPL group.A threshold corresponding to MFI +/- 4 standard error was then calculated for each group (see table 1), and patients were categorized following the expression profile of these 3 markers.Table 1:threshold calculated from the average MFI and the associated standard error for each studied pathologies.CD148CD180CD200MCL>980<1500<900CLL<680<1150>500MZL<1000>2700<2200LPL540 to 1350500 to 1450100 to 2700In this cohort, the above described profiles correctly identified MCL cases with a specificity of 96% and a sensitivity of 65%, CLL cases with a specificity of 95% and a sensitivity of 79%, LPL cases with a specificity of 95% and a sensitivity of 31% and MZL cases with a specificity of 99% and a sensitivity of 52%.These results strongly suggest that the incorporation of these three markers CD148 CD180 and CD200 in addition of the routinely used flow cytometry panel can be helpful in a number of cases for which the diagnosis remains difficult.