[1316] Immunophenotypic Differentiation of CD10 Positive B-Cell Lymphomas by Flow Cytometry.

Paul J McGowan, Jana Wimmer, Nicole Nelles, Choladda V Curry, Chung-Che Chang, Youli Zu, April Ewton, Andrea Sheehan. The Methodist Hospital, Houston, TX; Texas Children's Hospital, Houston

Background: A frequent problem in hematopathology is differentiation of CD10 positive B-cell lymphomas especially those sharing features of both Burkitt Lymphoma (BL) and Diffuse Large B-Cell Lymphoma (DLBL). In these cases fluorescent in situ hybridization for c-MYC can be useful, but nearly 10% of DLBLs may also have c-MYC translocations, and this test may take days. Specific methods for quickly differentiating between these two entities are needed.
Design: Twenty-five cases of confirmed follicular lymphomas (FCLs), BLs and (CD10-positive, c-MYC-negative) DLBLs were examined by four-color flow cytometry. Seven FCLs, twelve BLs and six DLBLs have been analyzed at this point. The same instruments, panels/fluorochromes, and software were used for all cases. The forward and side scatter heights (FSC-H and SSC-H) and the mean fluorescent intensities (MFIs) for CD20, CD10, CD38, CD79b, CD43 and CD71 were obtained for the atypical populations in each case. The data for each marker were compared using ANOVA.
Results: The MFIs for CD20, CD10, and CD79b were similar for all three groups. The FSC-H results were as follows: BL and DLBL > FCL. The SSC-H and the MFIs for CD71, CD38, CD43, results were as follows: BL > DLBL > FCL. No FCLs and only one DLBL had an SSC-H overlapping with the range for all BLs, and this same case was the only DLBL with a CD43 MFI with overlap. There were no FCLs or DLBLs CD71 or CD38 MFI's which were nearly as bright as MFIs from any BL.

table 1
BL (12) Mean (SD)2531 (1091)24481 (3034)2551 (1127)32058 (4392)
DLBL (6) Mean (SD)198 (145)6447 (4037)834 (1252)22523 (6527)
FCL (7) Mean (SD)192 (169)2618 (1619)543 (308)18187 (2707)
p value<0.000<0.0000.0030.001

Conclusions: The data from these initial 25 cases indicate that flow cytometry offers promise as a method to differentiate CD10-positive lymphomas, most importantly BLs and DLBLs. Not surprisingly, the BLs and DLBLs were significantly different from FCLs, but there was an unexpectedly striking difference in CD71 and CD38, particularly, for BLs and DLBLs. The additional markers can be tested for by flow cytometry in a matter of hours. In the experience of our flow lab, a CD71 MFI of 800 (FITC) and CD38 MFI of 19000 (APC) separated all the BLs from the DLBLs/FCLs tested. Currently, additional data are being obtained by analysis more cases as well as cases of childhood DLBLs and Burkitt-like (or Highly-proliferative) DLBLs.
Category: Hematopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 215, Wednesday Afternoon


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