Leukemia-specific serum from a child showing an immunofluorescent pattern distinct from J-5 monoclonal antibody...

Leukemia-specific human antibody was detected in a child with acute lymphoblastic leukemia (ALL) treated with chemoimmunotherapy. Chemoimmunotherapy consists of standard chemotherapy and subcutaneous injections of irradiated ALL cells with a biological response modifier. This ALL-specific serum reacted in 60 out of 67 (89.5%) children with ALL and was not reactive with normal cells. Furthermore, this ALL-specific serum showed a different immunofluorescent pattern on dual staining as compared with J-5 monoclonal antibody directed for common ALL antigen (CALLA; CD10). J-5 did not block the reactivity of ALL-specific serum, and vice versa, when CD10-positive ALL cell lines were used as targets. These findings suggest the possibility that there exists an ALL-specific antigen(s) which is different from CALLA and that this antigen(s) elicits a tumor-specific antibody response.