Eleven infants who were suspected clinically of having cows' milk protein sensitive enteropathy were fed with a protein hydrolysate formula for six to eight weeks, after which they had jejunal and rectal biopsies taken before and 24 hours after challenge with cows' milk protein. When challenged six infants (group 1) developed clinical symptoms and five did not (group 2). In group 1 the lesions developed in both the jejunal mucosa (four infants at 24 hours and one at three days), and the rectal mucosa, and the injury was associated with depletion of alkaline phosphatase activity. Infants in group 2 were normal. It seems that rectal injury that develops as a direct consequence of oral challenge with the protein in reactive infants may be used as one of the measurements to confirm the diagnosis of cows' milk protein sensitive enteropathy. Moreover, ingestion of such food proteins may injure the distal colonic mucosa without affecting the proximal small gut in some infants.
A series of 31 infants, 28 with cow's milk protein sensitive enteropathy (CMPSE) and 3 controls, was studied for severity and extent of mucosal damage of the upper small bowel in relation to the development of clinical symptoms. Following challenge with the offending cow's milk, 18 infants (Group 1) developed severe mucosal changes at both the proximal and distal small bowel mucosa and all of these infants presented with clinical symptoms. The other 10 infants (Group 2) who did not develop clinical symptoms following the challenge had less severe damage to the distal small bowel mucosa as compared to the proximal region. The histological score of both the proximal and distal postchallenge biopsies were significantly lower in Group 2 as compared to Group 1 infants. The mucosal disaccharidase and alkaline phosphatase levels were depleted in both the proximal and distal biopsies following challenge but the depletion was greater in the proximal than the distal biopsies. It is suggested that the extent and severity of mucosal damage to the proximal duodenum and jejunum have a critical bearing on the development of clinical symptoms.