Increased circulating levels of transcobalamin ii in gaucher's disease.

The presence of several serum protein abnormalities in Gaucher's disease prompted a study of vitamin B12 binding proteins, in which 14 of 15 consecutive patients displayed increased circulating transcobalamin II unassociated with elevations of serum vitamin B12 or other vitamin B12 binders. Transcobalamin II levels were most significantly increased in nine patients with disease severe enough to require splenectomy (P less than 0.01), but were not correlated with liver size or levels of any other laboratory feature of Gaucher's disease studied. Splenectomy, per se, did not alter circulating transcobalamin II. Chracterization of the binder in Gaucher's disease revealed identity with normal serum transcobalamin II in acid inhibition of vitamin B12 binding, chromatographic behavior, immunologic specificity and functional integrity in vitamin B12 delivery. This observation suggests a relation between reticuloendothelial-cell activity and transcobalamin II metabolism. Elevated transcobalamin II levels may provide an additional means for diagnosis and assessment of Gaucher's disease.