Cobalamin binding proteins (haptocorrin and transcobalamin) in human cerebrospinal fluid

The unsaturated cobalamin binding capacity of transcobalamin and haptocorrin was studied in cerebrospinal fluid (CSF) and plasma (P) from 37 reference individuals. These comprised 27 males and 10 females who underwent minor surgery in spinal anaesthesia. The 5th and 95th percentiles were as follows: P-Transcobalamin 300-870 pmol/l (median 550 pmol/l); CSF-Transcobalamin 90-540 pmol/l (median 194 pmol/l); P-Haptocorrin 75-290 pmol/l (median 159 pmol/l); CSF-Haptocorrin 10-41 pmol/l (median 21 pmol/l). No sex difference was found between the levels of haptocorrin or transcobalamin in plasma or cerebrospinal fluid. A positive correlation between P-Transcobalamin and CSF-Transcobalamin was found, whereas no correlation between P-Haptocorrin and CSF-Haptocorrin values was found. The plasma/CSF ratios of transcobalamin, haptocorrin, albumin and IgG indicated that the binders may be synthetized into the cerebrospinal fluid or are actively being transported into the cerebrospinal fluid.