Immunofluorescence Studies in Human Leukemia

Plasma obtained from patients with leukemia, was concentrated by high speed centrifugation and used to prepare antisera in rabbits. Unabsorbed, anti-human leukemia plasma and anti-murine leukemia virus (Rauscher) anti-sera showed similar immunofluorescence with normal and leukemia leukocytes. After absorption of these antisera with normal human antigens, normal cells were non-reactive and leukemia cells still reactive. Each antisera was shown to contain antibodies capable of cross reacting with and/or blocking the immunofluorescent reaction of cells from acute myelogenous, stem cell, or lymphatic leukemia cases. Pre-immunization rabbit serum and anti-human normal plasma antisera failed to show these reactions. These and antisera to other antigens (human globulin, Herpesvirus, adenovirus) were also non-reactive with acute phase leukemia cells. Such findings indicated a specificity for human leukemia cells by the described antisera and that human leukemia cells and Rauscher murine leukemia virus may have common antigens.

Serial studies on leukemia patients showed that the number and intensity of fluorescing cells varied with the clinical state of the patient. The three antisera gave similar reactions in acute leukemia. Differences were noted in remission. It was postulated that these differences were due to other cellular antigens, masked during the acute phase reaction. Leukocytes from patients with Hodgkin’s disease, lymphoma(s) and multiple myeloma also showed fluorescence when reacted with anti-murine leukemia. (Rauscher) virus anti-serum. Whether this common antigenicity with leukemia cells indicates similar altered cell growth and/or related etiology remains unresolved.