[IgG-IgM cryoglobulinemia with a purpura-arthralgia-nephritis syndrome]

The clinical and laboratory features in 7 patients with essential mixed cryoglobulinemia are presented. The clinical picture was characterized by arthralgia, purpura and glomerulonephritis (3 patients). The cryoprecipitate consisted of IgM and IgG, the IgM being monoclonal (3 patients) with anti-IgG activity. Depressed C4 and/or C3 values were detected in 5 patients and were not correlated with the presence of nephritis. The IgM levels were elevated in 5 patients. The possibility that the disorder represents an immune complex mediated vasculitis is supported by the ability of the cryoglobulins to activate the complement system and by the detection of immunoglobulins and/or complement in the vasculitic lesions in the glomerula or the skin. Treatment by plasma exchange, steroids and azathioprine or cyclophosphamide was followed by a definite improvement in the purpura and the arthralgia, whereas the proteinuria, microhematuria and hypocomplementemia were not affected by therapy.