Clinical significance and prognostic value of the T-B immunological classification of human primary acute lymphoid leukaemias.

50 cases of primary acute lymphoid leukaemia (A.L.L.) were analysed for the presence of T and B membrane markers on bone-marrow and/or peripheral-blood cells. 26% of cases were predominantly T-cell in type, 4% were B, the remaining 70%, without detectable membrane markers, were classified as "null" cell A.L.L. Of particular interest is the correlation between this immunological classification and the prognosis, since T-cell and B-cell A.L.L. were associated with a poorer prognosis than null-cell A.L.L. in terms of both median length of first complete remission and median survival. With one exception the T-cell cases were, according to the W.H.O. classification, of either the prolymphocytic or macrolymphoblastic type of A.L.L. and were more extensive than the comparable null-cell A.L.L. In contrast, cases of the W.H.O. prolymphoblastic and microlymphoblastic types were all found to be null-cell A.L.L. and were associated with the worst and best prognosis respectively. The correlation found between the immunological classification of A.L.L. and the prognosis means that patients with a poor prognosis can be selected for more intensive therapy.