WK Lee, It is not at all unusual for a B-precursor cell ALL to be CD45 negative (has been reported to correlate with prognosis) or CD13 positive (usually dim or moderate). As long as the TdT is positive and the MPO is negative, it's not difficult to diagnose this as B-precursor cell ALL. Staining for CD22 (with a PE-conjugated antibody) or CD79a may be helpful for confirmation, since these are usually positive with this diagnosis. One thing you would need to watch out for when using only one B-lineage antigen are the cases of AML with 8:21 translocation, which will generally express CD19 (but these are usually CD45 moderately positive and also express CD56 and MPO). Regards, Deborah B. Aquino, M.D. Director, Clinical Flow Cytometry and Cellular Immunology Laboratory U.T. Southwestern Medical Center Dallas, TX, USA
This archive was generated by hypermail 2b29 : Sat Mar 10 2001 - 19:31:30 EST