Antibody-mediated tissue damage. Hyperviscosity and other complications of paraproteinaemia.

The association between hypergammaglobulinaemia and raised serum viscosity has been recognised for more than 40 years. Waldenstrom (1944) described three patients in whom macroglobulinaemia was associated with increased serum viscosity, and even earlier than this there had been reports of raised plasma viscosity in myelomatosis (Albers, 1937). Since these early reports many of the clinical features of macroglobulinaemia have been recognised to be a direct consequence of the increased plasma viscosity, and in 1965 Fahey and his colleagues defined the condition now known as the hyperviscosity syndrome (Fahey et al., 1965). Initially it was believed that the hyperviscosity syndrome (HVS) was almost invariably associated with Waldenstrom's macroglobulinaemia and that it was a rare complication of myelomatosis. During the last few years, however, it has become increasingly recognised as a complication of certain types of myelomatosis (Preston et al., 1978; Tuddenham et al., 1974).