Usefulness of CD79b expression in the diagnosis of B-cell chronic lymphoproliferative disorders

We evaluated anti-CD79b for its usefulness in the diagnosis of B-cell chron ic lymphoproliferative disorders (BCLPDs), particularly chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). We analyzed 100 BCLPDs for CD5, CD19, CD20, CD23, CD79b, and surface immunoglobulin light chain (sIg) expression by 4-color flow cytometry CD20 CD79b, and sig expression Mere qu antified Correlational analysis and univariable and multivariable logistic regression models were used to determine the best combination of antigens f or the immunophenotypic classification of CLL vs other BCLPDs. Positive and statistically significant Spearman pairwise correlations between CD20, CD7 9b, and sIg fluorescence intensity were demonstrated. In the simplest model s in which a single variable was considered cutoff points were chosen that gave misclassification rates for CLL of 16% for CD79b, 19% for sIg, and 18% for CD20. Low-intensity CD79b, CD20, and sig are associated highly with CL L. A panel containing CD5, CD19, CD23, and sig allowed correct classificati on of most cases. Addition of CD20 or CD79b improved diagnostic accuracy; C D79b was slightly better than CD20. CD79b seems to be a useful addition to a standard flow cytometry panel for the evaluation of BCLPDs.