MIXED CRYOGLOBULINEMIA AND VASCULITIS - A NOVEL PATHOGENIC MECHANISM

We describe a patient with lymphoma and mixed cryoglobulinemia who dev eloped vasculitis and membranoproliferative glomerulonephritis concomi tant with severe decreases in serum IgG and complement levels. At the time of her demise, her serum cryoglobulin solubility had decreased co mpared to a specimen obtained when she was asymptomatic. This suggests that a change in antigen-antibody ratio of her cryoglobulin towards i mmune equivalence, due to decreased available antigen (IgG), was respo nsible for the development of immune complex vasculitis.