Cast Nephropathy and plasmapheresis

Does removal of the light chains with plasmapharesis reduce the severity of cast nephropathy? We know that renal failure is a terrible prognostic factor in multiple myeloma so fixing acute renal failure is important.

Renal failure comes in many different flavors with myeloma:

• Light chain deposition disease
• Heavy chain deposition disease that I have never seen but Steve Rankin had a case as a fellow.
• Amylloidosis
• Hypercalcemia
• Cast nephropathy

Only the last is amenable to plasmapheresis. Whether it works has been the subject of three prospective randomized studies:

1. Zucchelli 1988
2. Johnson 1990
3. Clark  2005 (PDF)

UPDATE

Though not randomized this recent article from KI should be of interest (Thanks Kyste):

Leung et al. Improvement of cast nephropathy with plasma exchange depends on the diagnosis and on reduction of serum free light chains. Kidney Int (2008) vol. 73 (11) pp. 1282-8.