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Flow Cytometric Detection of CD79a Expression in T-Cell Acute Lymphoblastic Leukemias

Raymond Lai MD, PhD, Jonathan Juco MD, Siow Fong Lee MSc, Susan Nahirniak MD, Wai S. Etches MD
DOI: http://dx.doi.org/10.1309/391R-93YF-DB4D-1L35 823-830 First published online: 1 June 2000


We evaluated the lineage specificity of CD79a in acute leukemias using 3-color flow cytometry in 58 consecutive cases. A panel of cell-surface antigens, including myeloid-associated markers, Bcell –associated markers, and T-cell–associated markers, was used. All cases of acute myeloid leukemia were CD79a–, whereas all cases of B-lineage acute lymphoblastic leukemia (ALL) were CD79a+. Three of 8 cases of T-cell ALL showed variable CD79a expression, indicating the presence of a blast subset expressing a relatively high level of CD79a. We investigated the clinical and pathologic characteristics of these 3 cases. All 3 cases had L1 or L2 morphology and expressed surface CD3. None of the other Bcell –associated markers were positive, although 1 case expressed CD13 and CD33. Uncommon random karyotypic abnormalities were identified in all 3 cases. Molecular studies demonstrated monoclonal gene rearrangement of T-cell receptor gamma in 2 of 3 cases. All 3 patients were 18 years old or younger; 1 patient did not enter remission, and 1 had disease relapse in 8 months. Our findings provide further support for the existence of a subset of T-cell ALL coexpressing CD3 and CD79a. Further study of the clinical and biologic significance of this subset may be warranted.

Key Words:
  • CD79a
  • Acute leukemia
  • Flow cytometry