SUMMARY Cows' milk-fresh, boiled, and processed in different ways for the domestic market, and various infant milk formulae-was investigated for its sensitising capacity in the guinea-pig after being fed for 37 days. The anaphylactic sensitising capacity was considerably reduced by heat-treatment. As heat becomes more intense and more prolonged so P-lactoglobulin and casein become less sensitising. It should be stressed that these were results from experiments on guinea-pigs drinking milk. Should they be found to apply to the human infant too, it seems that it would not be impossible to manufacture a non-sensitising but fully nutritive milk product. The sensitising capacity of fresh and boiled goats' milk was examined too, and it was found that boiling reduced the sensitising capacity to an even greater extent than was the case with cows' milk.

SUMMARY The quantitative measurement of the IgE and IgG subclass levels in the sera of 29 patients with atopic dermatitis has revealed significantly elevated levels of IgE and IgG4 in a relatively high proportion of patients with this condition compared to non‐atopic patients with warts and to a group of normal volunteers studied previously. The possible significance of these observations is discussed in relation to current evidence suggesting the involvement of IgG4 in certain immediate‐type hypersensitivity disorders.

Summary Basophil leucocyte‐bound IgE has been investigated in patients with chronic urticaria by the method of reversed anaphylaxis. In this reaction basophil‐bound IgE behaves as an antigen, the amount present being inversely proportional to the concentration of anti‐IgE producing maximum histamine release. Dose‐response curves in which histamine release was plotted against the concentration of anti‐IgE failed to reveal any substantial difference in the optimum concentration of anti‐IgE for maximum release from basophils of urticarial subjects compared with control subjects, thus suggesting there is no quantitative abnormality of basophil bound IgE in chronic urticaria. However, the magnitude of maximum histamine release by anti‐IgE from basophils of urticarial subjects was reduced compared with controls and this was not related to serum IgE concentrations since the mean serum IgE concentration was slightly higher in the urticaria group. Studies of spontaneous and compound 48/80‐evoked histamine release in the two groups did not reveal any differences in stability of histamine stores or in the biochemical histamine release mechanism over a wide range of concentrations of 48/80. These results raise the possibility of a qualitative abnormality of basophil bound IgE in chronic urticaria.

29 adult patients with nasal polyps were studied. The clinical symptoms and atopic profile were compared with both the level of histamine and IgE found in polyp fluid. The high concentration of free histamine found in polyp fluid was probably pathological, and local IgE was present in greater amounts than expected by simple diffusion. There was no evidence that clinical hypersensitivity is associated with higher concentrations of IgE and histamine in polyp fluid; it is possible that mechanisms other than an IgE-mediated response could cause degranulation of mast cells in nasal polyps.

Isolated epithelia from the colons of guinea pigs fed cows’ milk have been studied in vitro under short circuit current conditions. When challenged with β-lactoglobulin (βLG) from the basolateral side, a large, transient inward flowing current was recorded. Pharmacological and ion flux measurements indicated this was due to inappropriate chloride secretion. There was no effect of βLG on normal epithelia. The effects of challenge with βLG were abolished by pretreatment with indomethacin, a prostaglandin synthetase inhibitor. By exposing epithelia from water-drinking animals in vitro to serum from milk-drinking guinea pigs sensitivity to βLG could be conferred.

The epithelium lining the ileum has been isolated and studied in vitro under short-circuit conditions. Tissues were obtained from guinea-pigs fed cow milk. When challenged with β-lactoglobulin on either the apical or basolateral side, a transient, inward flowing current was recorded. This reaction did not occur with tissues from non-milk drinking animals. Casein and α-lactalbumin, in contrast to β-lactoglobulin, produced only minor effects while bovine serum albumin and bovine γ-globulin were without effect. The effect with β-lactoglobulin was associated with overall fluid secretion in the basolateral to apical direction, although the ions responsible for carrying the current have not been identified. Possible mediators of the response to β-lactoglobulin have been investigated. Throughout the responses of the ileum have been compared with those in the colon. The differences between the two tissues is striking. The relevance of the model to mechanisms of food intolerance is discussed.

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lation in target organs and to establish the role of aggregated immunoglobulins and heparin in complement activation.We thank our surgical colleagues Mr J R W Keates and Mr A Forsyth for permission to study patients in their care and all the technical staff of the cardiothoracic unit under the direction of Mr A Pastellopoulos. We are grateful to Miss D J Wright for the statistical computations. This study was funded by the British Heart Foundation and by the King's College Hospital joint research committee for locally organised research. Latent anaphylactic sensitisation of infants of low birth weight to cows' milk proteins A LUCAS, P McLAUGHLAN, R R A COOMBS Abstract Latent systemic anaphylactic sensitisation to cows' milk was assessed in 61 preterm infants who were randomly assigned to receive either a special formula for preterm infants based on cows' milk or banked breast milk or one or other of these as a supplement to maternal milk. A single sample of venous blood was taken near to the time of discharge from the neonatal intensive care unit, and the histamine release by blood basophils in response to in vitro challenge with cows' milk and anti-IgE was measured. Compared with the blood from infants fed on human milk, that from infants fed on preterm formula showed a significant increase in histamine release to challenge with cows' milk, the response being greater in blood from infants of lower birth weight and gestational age. A smaller but significant increase in blood histamine release with anti-IgE challenge was observed in the group fed on preterm formula. Infants of low birth weight fed on preterm formula based on cows' milk may develop latent systemic sensitisation more rapidly than infants born at term. The clinical importance of this requires further investigation. References