G-CSF Receptors on the Surface of Ph¹-positive Acute Lymphoblastic Leukemia (ALL) Cells with Myeloid Surface Antigens: ALL Cells with Myeloid Antigens have Myeloid Function

Abstract

We treated a patient with acute lymphoblastic leukemia (ALL) whose lymphoblasts at onset showed Ph¹ chromosome and expressed on their surface both precursor B-cell antigens (CD 19 and CD10) and myeloid antigens (CD13 and CD33). The blast cells from this patient showed enhanced ³H-thymidine (³H-TdR) uptake and monocytic differentiation when cultured with either granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage CSF (GM-CSF). The specific binding of ¹²⁵I-labeled G-CSF was also demonstrated. These observations imply that the Ph¹-positive ALL blasts with myeloid surface antigens have myeloid characteristics both phenotypically and functionally.

The disease was resistant to an ALL-oriented regimen but responded to the acute non-lymphocytic leukemia (ANLL)-oriented regimen, but relapses occurred. The cells at the first relapse had exclusively lymphoid markers while those at the second relapse bore myeloid markers; both showed G-CSF binding properties. The expression of G-CSF receptors on the surface of these blasts and responsiveness to G- and GM-CSF may explain the poor prognosis of such patients. All this evidence provides insight into the origin of these blasts.

Key Words:

• Ph¹-positive ALL
• mixed lineage leukemia
• CML in lymphoid blast crisis
• G-CSF receptor