SummaryLymphoblasts from patients with acute lymphatic leukemia were examined for the presence of surface markers and for their capacity to stimulate allogeneic donors in MLC. Lymphoblasts from eight patients, which made E rosettes, consistently failed to stimulate allogeneic donors on at least three separate occasions despite the vigorous response of these same allogeneic donors to remission cells from the patients.There were eleven patients who had lymphoblasts with no detectable markers or “null” lymphoblasts. Three of these also failed to stimulate in MLC. The “null” lymphoblasts from the remaining eight patients produced vigorous allogeneic responses. Since serologic data is now available suggesting that “null” lymphoblasts from some ALL patients have serologically detectable T cell antigens  while others have antigens found predominantly on B cells , it is conceivable that the capacity of these cells to stimulate in MLC may distinguish lymphoblasts within the “null” category with those which fail to stimulate representing early T cell precursors and those which do stimulate being early B cell precursors.
B. Leventhal, E. Leung, G. Johnson
Cancer Immunology, Immunotherapy