THERAPY OF MACROGLOBULINAEMIA

B-lymphoproliferative disorders: a proposed unified pathogenetic pathway

The clinical features of lymphoproliferative diseases associated with paraproteinemia are briefly reviewed and correlated with current immunologic concepts in an effort to clarify the pathophysiology of B-lymphocyte disorders. B-lymphocyte maturation proceeds in a predictable manner from the Pre-B cell to the formation of idiotype specific plasma cells and memory B-lymphocytes. The immunoglobulin isotype produced by the mature plasma cell is determined by a site specific process of gene switching which proceeds from mu to alpha production. Lymphoproliferative diseases are the result of disordered B cell maturation and their clinical features can be explained by identifying the locus of the maturational defect.

Polymerized monoclonal IgA in tuo patients with myelomatosis and hyperviscosity syndrome

Two cases of multiple myeloma with IgA gammopathy and the syndrome of serum hyperviscosity are reported. A common feature of both patients was the production of large amounts of polymeric IgA (more than 50% of the monoclonal proteins existed as dimers or larger forms). However, similar large amounts of polymeric IgA were present in sera with only slightly raised viscosity, suggesting that factors such as the molecular configuration of the polymers or their sub-units may play a role in determining serum viscosity. The association of plasmapheresis and chemotherapy produced remarkable improvements of the symptoms attributable to increased serum viscosity, and 16 months after diagnosis one of the patients has survived relatively free of symptoms. The hyperviscosity syndrome is being diagnosed with increasing frequency in association with IgA multiple myeloma, and should be investigated in all cases with monoclonal proteins exceeding a concentration of 3-0 g/dl.