Cryoprecipitation. In vitro studies on fibronectin as an independent cryoprecipitagogue.

Fifteen patients affected by essential mixed cryoglobulinemia or secondary cryoglobulins were studied. Fibronectin was detected in the majority of essential mixed cryoglobulinemias, but in a minority of secondary cryoglobulins. In vitro studies gave strong evidence of an interaction between fibronectin and heat-aggregated gammaglobulins. The effects of fibronectin on cryoprecipitation of heat-aggregated gammaglobulins seem to support the independent role of the glycoprotein in the cryoformation mechanism, although its presence does not appear essential for cryoglobulin appearance.