DNTT and acute lymphoblastic leukemia: Commencing with well-characterized polyclonal antisera, to T cells, B cells, heavy and light chains of immunoglobulin, the common acute lymphoblastic leukaemia antigen, and terminal deoxynucleotidyl antigen (TdT), these methods could establish that a leukaemia was of T- or B-cell origin, or to be a non-T or non-B (common) acute lymphoblastic leukaemia [3,4].