Cutaneous pre-B leukaemia cells with a T-lymphocyte antigen (T4)

A patient with acute lymphocytic leukaemia (ALL) is described in whom the cells originated in the pre-B cell lineage but showed an aberrant expression of T4 antigen. A B-cell origin of the leukaemic cells was indicated by reactivity for several monoclonal antibodies specific for the B-cell lineage and by cytoplasmic staining with FITC-labelled anti human mu chains.