Plasma exchange for treating cryoglobulinemia: a descriptive analysis.
BACKGROUND
Cryoglobulinemia is an immune-complex-mediated systemic vasculitis involving small-to-medium-sized vessels. Plasmapheresis transiently removes the circulating cryoglobulins and has been advocated (in conjunction with immunosuppressive therapy) to be effective in reducing morbidities associated with cryoglobulinemia. The goal of this paper was to review over the past 20 years the medical literature for evidence supporting or refuting the reported use of plasmapheresis for cryoglobulinemia (January 1988 through June 2008).


METHODS
We included all reported literature of the use of plasma exchange for the treatment of cryoglobulinemia that included at least five patients. Electronic searches were performed using MEDLINE (January 1988 through June 2008) and Cochrane Central Register of Controlled Trials (January 1988 through June 2008).


RESULTS
Of the 11 articles included in this review, there were a total of 156 patients studied. Two studies used cryofiltration, one compared plasma exchange to double cascade filtration and the other eight dealt with plasma exchange only. Outcome measures were often not clearly defined.


CONCLUSIONS
Although plasma exchange is an accepted treatment for cryoglobulinemia, there are no large multicentre randomized controlled trials of plasma exchange versus placebo or versus immunosuppressive therapy. Of the 11 studies from our literature search, none had a clear report of the apheresis procedures and clearly defined quantitative outcomes. The quality and variability of the evidence precludes a meta-analysis or even a systematic analysis. However, these studies weakly support the use of plasma exchange largely on a mechanistic basis.
Rockx
M A
MA
London Health Sciences Centre, London, ON, Canada.
Clark
W F
WF
D003131:Combined Modality Therapy; D003449:Cryoglobulinemia / Q000628:therapy*; D005374:Filtration / Q000379:methods; D006801:Humans; D010951:Plasma Exchange