Plasma exchange in the treatment of essential mixed cryoglobulinemia nephropathy. Long-term follow up.

Plasma exchange is increasingly used for management of Essential Mixed Cryoglobulinemia. However little is known about the long term effects of this treatment. Therefore we have reviewed the clinical and laboratory data of 20 patients with type II EMC who were followed for a mean of 24 months. 16 patients had renal involvement, which was characterized histologically in all of them: 9 had diffuse proliferative GN plus endoluminal "thrombi" in 6 and vasculitis in 5, 4 had lobular membranoproliferative GN and 3 had focal proliferative GN. 14 patients had renal failure and 13 had proteinuria greater than or equal to 2 g/24 hr. PE (combined with immunosuppressive drugs in 18) was performed for a mean of 18 procedures. The combined treatment induced prompt remission of extrarenal and renal involvement. Serum creatinine and proteinuria decreased significantly in all but 2 patients during the treatment (s. creatinine from 2.9 to 1.6 mg/dl; proteinuria from 3.5 to 1.6 g/24 hr). Analysis of long term follow up revealed that these effects were long lasting in all the cases. We conclude that PE should be used for EMC nephropathy whenever prompt remission is not obtained by conventional therapy especially in consideration of its long term beneficial effects.