Intrinsic factor in tropical sprue.

Criteria used to establish the diagnosis of tropical sprue were previously published.5 Twenty-one of the patients with sprue and four of the normal subjects were Puerto Rican. The patients with sprue ranged in age from 15 to 74 and the normal groups from 25 to 56. Treated patients were receiving folic acid orally, 5 mg. daily. Gastric juice was collected before and for 90 mm. after subcutaneous injection of histamine phosphate 0.01 mg/Kg. body weight. After the pH of the gastric juice was measured with a Beckman pH meter, it was depepsinized,3 brought to pH 7. and stored at -20 C. or lower until assayed. Intrinsic factor was assayed by the method of Cottlieb et al.,4 except for the use of 10 ng. 57cobalt vitamin B1., instead of 7.5 ng. of #{176}#{176}cobalt vitamin B19. This method is based on the observation that protein-coated charcoal adsorbs free B1 but not B12 combined with binding substances in gastric juice, thus allowing measurement of the unsaturated B12-binding capacity. By blocking binding of B19 to intrinsic factor with an antibody to intrinsic factor,#{176} the pencentage of the total gastric juice B1., binding capacity clue to intrinsic factor is assayed.