Alterations of HLe-1 (T200) fluorescence intensity on acute lymphoblastic leukemia cells may relate to therapeutic outcome.

Quantitative differences in HLe-1 expression were studied on normal lymphocytes and lymphoblasts of patients with acute lymphoblastic leukemia (ALL). A relationship was found between quantitative antigen expression and therapeutic outcome. Alterations in fluorescence intensity (FI) were demonstrated using quantitative flow cytometric methods and the monoclonal antibody (MoAb) anti HLe-1 (T200). Lymphoblasts from patients with ALL produced FI peaks ranging form channel 17 to 112 (mean 68; n = 28), while normal lymphoid cells were at FI channel 127 +/- 3 (n = 121). Patients with the dimmest-staining lymphoblasts (channels 17-50) responded better to therapy than those with brighter-staining cells (channels 50-100). Data from this pilot study suggests that the FI of malignant lymphoblasts has implications in the clinical response to therapy.