Changes of the immune response due to the absorption of antigenic protein or peptides.

Rabbits immunized against human gammaglobulin (HGG) were fed with either intact HGG or pepsin-digested HGG. Circulating antibodies were determined over an absorption time of 4 h. The oral application of antigenic peptides reduced circulating antibodies from 550 micrograms/ml to 120 micrograms/ml. A further parenteral antigen exposure to 50 mg HGG revealed that orally pretreated animals are protected against a marked blood pressure decrease due to antigen antibody reactions. One possible explanation for this phenomenon is that circulating antibodies are fixed in the wall of the gut by enterally applied antigenic peptides and eliminated into the lumen of the gastrointestinal tract. If this phenomenon can be extrapolated to human beings it would be a new therapeutic concept for the treatment of diseases in which circulating antibodies are of importance.

Protracted diarrhoea: secondary monosaccharide malabsorption and zinc deficiency with cutaneous manifestations during total parenteral nutrition.

Protracted diarrhoea in early infancy gives rise to many diagnostic and therapeutic problems. Jejunal biopsy often reveals villous atrophy of varying degrees. Severe reduction of small intestinal absorptive area causes secondary monosaccharide malabsorption, as well as secondary disaccharide deficiency, consequences which are relevant in any attempts at oral feeding. Morphologic, metabolic, endocrinological and microbiological studies have to be undertaken in order to establish a definitive diagnosis in protracted diarrhoea, but these studies often fail to reveal the aetiology of the disease. Immunologic abnormalities like phagocyte dysfunction, thymic atrophy and hypoplasia of B-cell regions in lymph nodes might be secondary events, but some types of immunodeficiency are of primary importance in the development of protracted diarrhoea. Total parenteral nutrition in many cases has to be instituted, with all its implications and hazards: septicaemia is the most dangerous of these. Zinc deficiency and acrodermatitis enteropathica may occur during total parenteral nutrition, and zinc deficiency secondarily contributes to the symptoms of diarrhoea. Parenteral administration of zinc is able to overcome these effects.