bone pain,
anaemia,
infections (defects in humoral not cell immunity),
renal failure,
proteinuria in 50% of patients excreting abnormal amounts of Bence Jones proteins (light chains),
hyperviscosity syndrome
electrophoresis of serum or urine shows a monoclonal protein in 90% of patients,
increased serum calcium,
low haemoglobin,
raised mean cell volume (MCV) and
increased erythrocyte sedimentation rate