[Successful treatment of kappa light chain nephropathy using membrane plasma separation].

Often the diagnosis "light chain nephropathy" is not made before renal failure has developed. In the past these patients had a poor prognosis. Special features of this disease and improvement of renal function by plasma exchange therapy are shown in a case report. A 51-year-old man admitted to hospital with renal failure, proteinuria and hypercalcaemia was treated by Ca-free dialysis and membrane plasma separation (MPS). Renal biopsy studied by light and electron microscopy showed mainly tubular protein casts. It is assumed that this nephropathy is caused by a direct toxic effect of the kappa light chains on function and structure of tubuli. Proteinuria was markedly lowered and renal failure was made partly reversible by prompt and effective MPS. Thus, MPS may improve the prognosis of this stage of disease.