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Increased gastrointestinal absorption of intact antigen with systemic immunization has been considered a major etiologic factor in the development of food sensitivity. We attempted to test this hypothesis in infants with suspected food protein-induced entercolitis by measuring serum ovalbumin (OVA) concentrations after ingestion of egg white (prior to the performance of good challenges to establish this diagnosis). We first noted significant underestimation of serum OVA concentrations in the presence of even low serum anti-OVA antibody concentrations (greater than 1:12). Next, using selected noninhibitory sera, we found that all infants studied absorbed some OVA, there was no correlation between serum OVA levels and age (3-11 months), and there was no significant difference between serum OVA concentrations in infants who subsequently had positive oral food challenge responses (120 +/- 67 ng/ml) and a matched group with negative challenges (102 +/- 80). These data do not support the hypothesis that "intestinal closure" (antigen exclusion) occurs in the neonatal period or the role of antigen absorption as the major etiological factor in the development of food sensitivity. Better methods of quantitating macromolecular absorption must be developed before the role of antigen absorption in food sensitivity can be assessed. Of note, urinary excretion of intact OVA also occurred. This varied greatly from one voiding to the next and continuing for at least 13 hr after ingestion.

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The serum levels of copper (Cu) and ceruloplasmin (Ce) of low-birth-weight infants (n.6) fed enriched formula (E) containing 0.2mg of copper/dl were compared t o the levels in low-birthweight infants (n=6) fed control formula (C) containing 0.06mg of copper/dl f o r a period of 29 days and were compared t o the i n f a n t s ' postnatal and gestational age. A t day 15 Cu levels in E and C infants were comparable while Ce levels were higher in E than C patients. Copper levels i n an E twin were significantl y higher than the C twinmate throughout the study period (days 1-29). Levels of ceruloplasmin remained elevated in the E twin following the termination of the study (day 29) when routine formula was fed t o both infants. These data suggested t h a t E formula enhances serum ceruloplasmin low-birth-weight infants compared t o control formula. Supported in part by a University of Oklahoma Health Sciences Center grant award and through research support through Ross Laboratories, Columbus, Ohio. Levels of copper (Cu) (N=17) and manganese (Mn) (N=12) were evaluated i n infants before and following a double volume exchange transfusion and compared t o levels of these elements i n donor blood. The change i n serum copper levels following exchange transfusion was s i g n i f i c a n t (P.0.037). Exchange transfusion did not s i g n i f i c a n t l y a1 ter manganese levels. Following an exchange transfusion, serum Cu levels a r e s i g n i f i c a n t l y elevated while serum manganese levels remain unchanged. This study supported i n part by a University of Oklahoma Health Sciences Center Small Grant Award. Enhanced macromolecular absorption of food antigens has been sugpected i n a v a r i e t y of c l i n i c a l disorders, but a method f o r evaluating t h i s i n humans has not been established. W e developed a& ELISA assay t o detect ovalbumin i n urine and serum. A s o l i d phase sandwich assay using commercial anti-ovalbumin antibodies (ZOA) detected a s l i t t l e as 10 ng/ml of ovalbumin. Urine did not i n t e r f e r e with t h e assay but serum containing BOA reduced assay s e n s i t i v i t y up t o 97%. However, serum inhibition d i d not occur i f BOA were not detected i n baseline serum. W e evaluated ovalbumin absorption i n infants < 1 year of age undergoing diagnostic food challenges t o soy and cow milk protein one month a f t e r recovery from e n t e r o c o l i t i s . Serum was obtained a t 1-hour post ingestion of a standardized o r a l dose of egg white ( . 6 gm protein/ kg) and urine collected f o r 12 hours. Ovalbumin was detected i n t h e serum i n 14 of 15 infants and i n t h e urine i n 8 of 10 infants. The mean serum 1-hour concentration was 105 ng/ml (range 0 t o 218, n=15). The mean 12-hour urinary excretion was 5.3 x 10-'percent of ingested dose (range 0-2100, n=6). No correlation between ovalbumin absorption and age, t o t a l serum immunoglobulins o r c l i n i c a l response t o challenge could be demonstrated. Thus by evaluating both serum and urine a f t e r a standardized e...