Diagnostic usefulness of CD23 and FMC-7 antigen expression patterns in B-cell lymphoma classification

CD23 and FMC-7 are normal B-cell antigens used during diagnostic immunophen otyping of suspected lymphoproliferative disorders, but the diagnostic usef ulness of antigenic expression patterns of simultaneous 2-color staining an d flow cytometric analysis has not been reported We evaluated the FMC-7 and ! CD23 expression pattern in 201 cases of B-cell lymphoma from tissue biops y specimens by multiparameter flow cytometry. The CD23-/FMC-7+ pattern was the most common pattern in large cell, mantle cell, and marginal zone lymph omas. The CD23 and FMC-7 antigen, along with the CD5 coexpression pattern, permitted accurate classification of all 71 cases of small lymphocytic, man tle cell, and marginal zone types of lymphoma. The widest variation of patt erns was with follicular cell lymphoma, although most cases expressed the C D23+/-/FMC-7+ pattern (+/-, partial or minor subset expression). The CD23 a nd FMC-7 antigen expression pattern was predictive of subtypes in more than 95% of lymphoma cases and could narrow the differential diagnosis in the r emaining cases. We conclude the flow cytometric CD23/FMC-7 expression patte rn achieved by dual staining facilitates accurate and reproducible classifi cation of B-cell lymphomas and has diagnostic usefulness.