Continuing with this case, note that 0% of the cells are positive for CD10, and 10% are positive for HLA-DR. The percentages of cells positive for Kappa and Lambda are 4% and 3%, respectively. The results thus far are:
CD19= 7%
CD20= 7%
HLA-DR= 10%
Kappa=4%
Lambda=3%
CD10= 0%
Given this information, follicular lymphoma can be ruled out because CD10 is not present. Referring to the decision tree on the right, the CD10 surface marker would be positive with follicular lymphoma.
Kappa and Lambda light chains are expressed with the normal 2:1 ratio, which helps to rule out a B cell neoplastic process. A malignant, clonal population would be suspected if the B lymphocytes expressed only one type of light chain (kappa or lambda) or one predominated significantly.
It is important to also examine the T cell results to determine whether or not there is a normal representation of the expected antigens.
