Contribution of immunological markers to the diagnosis and prognosis of human leukemia.

Surface markers have been of proven diagnostic and prognostic use in acute lymphoblastic leukemia (ALL). T cell ALL (T-ALL), where blasts possess receptors for sheep red blood cells (R-SRC+), is associated with an adverse prognosis in children and adults. The presence of common ALL antigen (CALLA)-positive blasts (i.e. common-ALL) in children is indicative of a good response to treatment, in contrast to the poor response shown by pre-B-ALL cases, where the blasts are also CALLA-positive but additionally contain cytoplasmic mu chains. Recently a subgroup of T-ALL, immature T-ALL, was identified, where the blasts lack R-SRC and T cell markers (such as T1, T3, T4, T8, T6) but carry a pan T cell antigen (p40) recognized by the monoclonal antibody LAU-A1(12/103 ALL cases in our series). This new subgroup, immature T-ALL (R-SRC-/p40+), also seems to be associated with a poor prognosis, like T-ALL.