Abnormalities in the expression of the leucocyte-common antigen in chronic lymphocytic leukaemia.

The surface glycoproteins of lymphocytes isolated from patients suffering from B cell chronic lymphocytic leukaemia (B-CLL) have been studied by radioactive labelling with impermeable probes and with MoAb. Several features not found in normal B cells have been observed. The abnormalities found in the expression of polypeptides of the leucocyte common (L-C) antigen, identified by appropriate MoAb, have been examined in detail. It has been shown by both biochemical analysis and MoAb binding that this group of polypeptides can, within a panel of B-CLL patients, range from a typical B cell pattern to the pattern resembling that normally found in T cells. The T lymphocyte profile is correlated with a poor prognosis (MVA C rating) and in the one patient where a change in the glycoprotein profile towards that of the T cell was observed, the change coincided with a clinical deterioration. The biological significance of the molecular diversity is discussed.