Charles D. May

Proper use of skin tests with food extracts in diagnosis of hypersensitivity to food in children.

This study was undertaken to determine the proper use of skin tests with food extracts in diagnosis of hypersensitivity to food in children. Cutaneous reactions evoked by graded amounts of food extracts were compared with results of double‐blind food challenge and in vitro release of histamine from leucocytes. A 3 mm or greater weal reaction in skin tests by puncture technique using food extracts of 1:20 w/v concentration was found to indicate the degree of hypersensitivity likely to be associated with clinically significant hypersensitivity reactions to food. Proper use of this simple technique will facilitate accurate diagnosis of food hypersensitivity in children by identifying the group among whom all positive reactions to food challenges will be found. Nevertheless, double‐blind food challenge is essential to establish a diagnosis of symptomatic hypersensitivity to food.

A study of serum antibodies to isolated milk proteins and ovalbumin in infants and children

Serum antibodies to cow milk proteins and ovalbumin were measured quantitatively. Food hypersensitivity of the immediate type was determined to be present or absent by skin tests and double‐blind food challenges. Elevated levels of antibodies to milk proteins in sera characteristic of infants fed cow milk were found to decline with age, so that sera from children who were 6 to 15 years of age (inclusive), not hypersensitive to food, had significantly lower levels than the infants. In contrast, sera from age‐matched children, who were shown to have hypersensitivity to some food, were found to have levels of antibodies to milk proteins as elevated as in infancy. Hypersensitivity was not necessarily to milk but often to some other food. This persistence of greater antibody production to milk throughout childhood in those hypersensitive to some food indicates a fundamental difference from those without hypersensitivity to food, either in permeability, in immunological reactivity of the gut or in development of immunological unresponsiveness. Implications for pathogenesis of clinical disorders are discussed.

Usefulness of Measurement of Antibodies in Serum in Diagnosis of Sensitivity to Cow Milk and Soy Proteins in Early Childhood

A noteworthy feature of this study is that comparisons were made between specific, sensitive, quantitative measurements of serum antibodies to food proteins and objective appraisal of clinical manifestations buy double‐blind food challenges. Over 50 children, 4–30 months of age, with suspicious histories of adverse reactions to cow milk or soy products were investigated. Levels of serum antibodies to cow‐milk proteins were clearly higher in children with adverse reactions to milk, confirmed by blind challenge; there was no overlap with the lower levels of serum antibodies in children without confirmed reactions. Findings with serial determinations of serum antibodies to cow milk in selected cases are also presented.

Observations on high spontaneous release of histamine from leucocytes in vitro

Clinical and laboratory observations are provided on high, spontaneous, in vitro histamine release (HSHR) from leucocytes (basophils), meaning without addition of antigen or other inducers of histamine release. HSHR has been observed predominantly in persons with a high degree of reaginic sensitivity to food; the leucocytes of forty‐eight of fifty‐eight individuals (83%), who had positive reactions to foods in double‐blind challenges, exhibited HSHR. HSHR resembles antigenic release in a wide variety of characteristics. HSHR does not occur in vivo but only in vitro after compaction of leucocytes by centrifugation at room temperature. An indispensible requirement for HSHR to occur appears to be a high degree of reaginic sensitization.

Food allergy: lessons from the past

Because finite studies are customarily published as the observations are completed, general principles and unifying concepts may be difficult to discern. When the contributions to a field of study are viewed in retrospect and in their entirety, the concepts and common understanding that influenced the kind of observations made and the interpretations of the findings may be more apparent. Periodic attempts to identify obstacles to scientific progress in the past should serve to lessen the clutter in the path of further advancement of knowledge. The need for this exercise in the field of food allergy has been urgent, and this is an effort to that end.

Effects of injections of allergen extracts on antigenic release of histamine from leucocytes, skin tests and bronchial challenge in allergic children

Leucocyte sensitivity to antigenic release of histamine was determined in allergic children receiving injections of allergen extracts in order to ascertain the frequency of development of complete loss of sensitivity (unresponsiveness). Leucocyte unresponsiveness did not occur in any of eight allergic children given large doses of allergen extracts by an intensive regimen of injections. In only two of twenty‐three children who had received injections of allergen extracts by a customary dosage regimen, were the leucocytes found to be unresponsive to antigenic histamine release. These findings confirm our earlier reports.

Food Allergy: A Commentary

In the absence of means for rigorous identification of the immunologic mechanisms, uncritical claims of relations of foods to symptoms can be expected, and unsupported “systems” of diagnosis and treatment will flourish.

Treatment of Allergic Disorders with Injections of Allergen Extracts

A series of investigations did not reveal an immunochemical response to injection of allergen extracts into sensitive persons which would provide either a rationale for the treatment or a basis for a promising dosage regimen worthy of clinical trial. Properly conducted clinical trials are thus still relied on.