Massive hollow fiber clotting: a distinct problem in treatment of cryoglobulinemia by membrane plasmapheresis.

Two patients with cryoglobulinemia were treated with plasmapheresis in combination with immunosuppressive therapy. One had Waldenstrom's macroglobulinemia, and the other suffered from systemic lupus erythematosus. Membrane plasmapheresis, using membrane plasma separators, was performed, and the initial plasmapheresis treatments were unsatisfactory because of clotting of hollow fibers by cryoglobulin. The plasma filtration rate and the clearance of immunoglobulins fell rapidly with the clotting of the hollow fibers. This technical difficulty was overcome by prediluting the blood with normal saline before passing it through the membrane plasma separator. The mechanism of preventing clotting of hollow fiber by saline predilution is likely to be the reduction of serum viscosity and the lowering of cryoglobulin concentration. This modification is simple and efficient and enables membrane plasmapheresis to be performed effectively in patients with cryoglobulinemia without complicated and expensive machines.