Originally, we were staining patient specimens with CD3-FITC / CD19-PE
as part of our CLL panel. When we began to incorporate 3-color
techniques into our protocols, we attempted to add CD19-PerCP to the
BD kappa-FITC/lambda-PE tube. Even though BD markets two CD19
clones conjugated to PerCP, both reagents were dim or even negative in
many patients who were CD19-PE positive. Now we make a cocktail of
BD's kappa/lambda with CD20-PerCP. Even though B CLL often
demonstrates dim CD20, we have had better luck with this combination in
attempting to demonstrate light chain restriction than using the
CD19-PerCP. In addition, this combination allows us to target the
aberrant dim CD20 cells in the presence of normal B cells. Incidently,
we run CD5-FITC / CD20-PE / CD45-PerCP in the CLL panel as well.
Good Luck!
Cathy Fritschi
Sentara Norfolk General Hospital
Norfolk, VA