The Role of CD34 in the Immunophenotyping Panel of Leukemia

Choi, Mi Yeon; Kim, Think You; Lee, Woong Soo

Abstract

BACKGROUND: CD34 is expressed by early hematopoietic (myeloid & lymphoid) progenitor cells, endothelial cells, and bone marrow stromal cells. Recent studies have suggested that the expression of the hematopoietic antigen CD34 is predictive of outcome. But the functional importance of CD34 antigen has not yet been fully elucidated, and CD34 antigen has not yet been included in the routine immunophenotyping panel. We designed this experiment to evaluate the significance of including CD34 antigen in the routine immunophenotyping panel.
MATERIALS AND METHODS
We have included CD34 antigen in the immunophenotyping panel from 1994 to 1997. Seventy eight patients with acute leukemia and 7 patients with chronic leukemia and CML-blast crisis were analyzed by direct immunofluorescence using monoclonal antibodies.
RESULTS
CD34 was positive in 64% (50/78) of cases with acute leukemia and 100% (3/3) of cases with CML-blast crisis, but negative in 100% (4/4) of cases with chronic lymphocytic leukemia. Seventeen (63%) of 27 patients that belonged to AML FAB subtype M0, M1, M2, M4, M5, M7 were CD34-positive, but all of the 9 patients (100%) that belonged to AML FAB M3 were CD34-negative. Thirty-one patients of CD34-positive non-T-ALL belonged to immunologic group II, III, or IV, and all 2 patients of CD34-positive T-ALL belonged to immunologic group I. There are no significant correlations of CD34 with the remission rate and the survival rate of acute leukemia.
CONCLUSIONS
CD34 facilitates the rapid diagnosis of acute promyelocytic leukemia (APL) different from the other AML subtypes in clinical course and therapeutic plan. It is also helpful for the immunologic grouping of ALL, and differentiation of chronic leukemia from CML-blast crisis or acute leukemia. We concluded that it is desirable to include CD34 in the routine immunophenotyping panel.