PROGNOSTIC-SIGNIFICANCE OF MYELOID-ASSOCIATED ANTIGEN EXPRESSION ON BLAST CELLS IN CHILDREN WITH ACUTE LYMPHOBLASTIC-LEUKEMIA

The prognostic significance of expression of myeloid-associated antige ns in childhood acute lymphoblastic leukemia (myA+ ALL) was evaluated. From 1984 to 1990, 251 children with immunologically verified ALL wer e treated in two prospective consecutive Austrian studies. Complete im munophenotyping was performed in 206 cases (82%). Out of these 175 cas es were classified as B-cell precursor ALL, 31 cases as T-ALL. Express ion of myeloid-associated antigens was demonstrated in 23 cases (13.1% ) of childhood B-cell precursor ALL, particularly in immature (CD10 ne gative) forms (P < .0001), and in 1 case (3.2%) of T-ALL. CDw65 was ex pressed most frequently (12 cases), followed by CD13 and CD15 (5 cases each), CD33 (4 cases), and blood-group H (3 cases). Compared to myA- ALL prognosis of children with myA+ B-cell precursor ALL was poor, des pite intensive multiagent chemotherapy according to BFM protocols. Rem ission rates were not impaired, but pEFS was 74.6% for myA- ALL, and o nly 37.8% for myA + ALL (P = .0001). As demonstrated by multivariate a nalysis the expression of myeloid-associated antigens was the most imp ortant prognostic variable for EFS in B-cell precursor ALL, whether or not CD10 was expressed.