Blood Journal
Leading the way in experimental and clinical research in hematology

Asynchronous antigen expression in B lineage acute lymphoblastic leukemia

  1. CA Hurwitz,
  2. MR Loken,
  3. ML Graham,
  4. JE Karp,
  5. MJ Borowitz,
  6. DJ Pullen, and
  7. CI Civin
  1. Johns Hopkins Oncology Center, Pediatric Oncology, Baltimore, MD 21205.

Abstract

Cell surface phenotypes of 113 B lineage acute lymphocytic leukemia (ALL) cases, defined by the presence of HLA-DR and at least one B-cell- specific antigen (either CD19, CD20, or CD22), were compared with antigen-defined stages of normal B lymphocyte development. The cases were first evaluated for expression of HLA-DR, CD19, CD34, CD10, CD20, and CD22 by indirect one-color immunofluorescence. Pairwise comparisons of cell surface marker expression were performed for each leukemic sample: no correlations were observed for paired antigen expression on the leukemic samples using antigens expressed either early or late during normal B lymphoid development. Complete immunophenotypes of the cases were then compared with normal B-cell developmental stages. Sixteen different complete immunophenotypes were observed on the leukemias that were not found in normal marrow; at least 78% of the cases demonstrated such “asynchronous” combinations of B lymphoid- associated differentiation antigens. Several samples were subsequently studied by two-color immunofluorescence, and the presence of doubly labeled cells with “asynchronous” antigen combinations was confirmed. These results indicate that the majority of B lineage leukemias exhibit “developmental asynchrony,” as compared with normal marrow B cells. The data further suggest that ALL cases do not accurately represent cells arrested at the stage where the leukemogenic event occurred. Rather, ALL appears to be a disease in which there may be maturation of leukemic blasts; but this maturation is “asynchronous” when compared with the normal developmental process.