Plasmapheresis and chemotherapy of hyperviscosity syndrome associated with monoclonal gammopathy in the dog.

Hyperviscosity syndrome associated with IgA monoclonal gammopathy was diagnosed in 3 dogs. Continuous plasmapheresis and alkylation therapy with melphalan and cyclophosphamide induced sustained remission in each dog. There was resolution of clinical signs associated with hyperviscosity syndrome and rapid establishment of normal serum protein concentrations.