The B cell analysis produced the following results (abnormal findings are highlighted in yellow):
- CD19 = 81%
- CD20 = 82%
- HLA-DR = 83%
- Kappa = 80%
- Lambda = 1%
- CD19+/CD5+ = 81%
- CD10 = negative
- CD45 = 99%
Two apparent abnormalities are present; the B cells are clonal because they express primarily Kappa light chains and the B cells are positive for CD5, which is not normally present on B cells.
If Kappa or Lambda is predominant and CD5 is co-expressed with CD19 (CD19/CD5 dual positive lymphocyte population), B-cell chronic lymphocytic leukemia (B-CLL) is a possible diagnosis. In order to confirm this finding, it is important to determine whether or not CD23 is present. The flow cytometry pattern can look identical for B-CLL and Mantle Cell Lymphoma (MCL), except CD23 is generally positive in B-CLL and negative in MCL, as shown in the decision tree on the right.
This particular case does have CD23 = 82%.
Therefore, the final interpretation of Case Two is B-CLL.