Relation of vitreous amyloidosis to prealbumin.

Amyloid fibrils were isolated from the vitreous of 9 patients with familial amyloidosis. The material of all patients contained proteins reacting in double immunodiffusion with an antiserum against an amyloid protein which previously has been shown to be prealbumin-related. Two out of five tested vitreous amyloid materials also showed a reaction of identity with antihuman prealbumin. It was shown by electrophoresis that the amyloid subunit consisted of two low molecular weight components, one in size similar to prealbumin and one slightly smaller, which appears to be a degradation product of prealbumin. The proportion between the two components seems to vary. It is concluded that besides the presence of an abnormal prealbumin, other factors are of importance for the formation of amyloid precipitates in the vitreous.