pyroglobulin

[pī′rō-glŏbyə-lĭn]
n.
  1. Any of various immunoglobulins that coagulate when heated, usually associated with multiple myeloma or macroglobulinemia.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.