Serum B₁₂ Binders in Vitamin B₁₂ Deficiency

Abstract

In 74 adults with serum B₁₂ Z. 140 pg/ml with or without anaemia, unsaturated B₁₂-binding capacity (UBBC), total B₁₂-binding capacity and transcobalamin I and II (TC I, TC II) were determined using ⁵⁷Co B₁₂. The results were statistically analysed in relatíon to severity of anaemia and vitamin B₁₂ deficiency. In severe vitamin B₁₂ deficiency, TC II was reduced and contributed to the reduction of UBBC. Greater unsaturation and moderate increase in total TC I were also seen. It is suggested that anaemia is a contributory factor in the moderate increase of TCI. On the basis of limited evidence presently available, it is argued that abnormal intestinal structure and function associ; ciency may result in impaired synthesis of TC II.