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:
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.
You also can cite Leung in KI 2008 (its a very important analysis of the confused results of the previous three studies). It is important to biopsy the myeloma associated nephropathy if you want to use plasmapheresis.
There will be certainly improvement with the use of new dialysis membranes (HCO-HD), Hutchinson CA CJASN 2009.
I think that the more important thing is to diagnosis very early the myeloma to begin the real treatment of cast nephropathy: chemotherapy.