Monoclonal Bence Jones proteinuria in chronic lymphocytic leukaemia.

A series of 52 consecutive patients with newly diagnosed chronic lymphocytic leukaemia (CLL) was investigated for the presence of serum and urine monoclonal immunoglobulins. The overall incidence of monoclonal gammopathy (MG) was 69%. Serum M components belonging to the IgG and IgM classes were found in 27% of cases with a concentration ranging from 1.7 to 40.3 g/l (mean 10 g/l). A monoclonal free light chain, i.e. Bence Jones protein (BJP), was documented in the urine of 65% of cases. In 42% of the 52 patients the urinary excretion of BJP represented the sole detectable monoclonal immunoglobulin abnormality. The occurrence of serum monoclonal immunoglobulins was not found to correlate with the stage or progression of the disease. Conversely, the isolated urinary excretion of BJP showed a relationship with the tumour load, as evaluated in terms of clinical enlargement of lymphoid areas. The presence of BJP alone was also a major distinctive feature of patients with more aggressive disease. These preliminary data would suggest that the isolated urinary excretion of BJP may represent a parameter of clinical significance in evaluating patients with CLL.