Specific translocation t(4;11) in an infant with acute lymphoblastic leukaemia of null cell type.

A case of acute lymphoblastic leukaemia of null cell type in infancy showed the specific reciprocal translocation t(4;11) (q21;q23) reported 16 times so far in the world literature. The proportions of abnormal and normal metaphases throughout the course of the illness correlated well with the clinical picture, but even during the short term remission metaphases expressing the translocation were still identifiable in appreciable numbers. Comparison between cytogenetic analyses of cultured and native bone marrow, PHA-stimulated and non-stimulated peripheral blood demonstrated the gradual conquest of the periphery by the abnormal clone. The importance of chromosomal changes and their interpretation for diagnosis, classification and prognostic judgment in haemotologic neoplasms is discussed in the light of the reported case.