IgG Cryoglobulinemia Associated With Amyloidosis

A patient with symptomatic primary cryoglobulinemia was followed for 9 yr and was found at autopsy to have generalized amyloidosis. There was a monoclonal serum protein spike of IgG kappa type that was cryoglobulin. The cryoglobulin was further characterized as IgG₂ kappa Gm (n-). This case constitutes, to our knowledge, the first example of amyloidosis associated with monoclonal IgG cryoglobulinemia, with characterization of the monoclonal serum cryoglobulin, and also the first reported case of successful symptomatic treatment of cryoglobulinemia by plasmapheresis.