Dose response relationships and interference of simultaneous skin tests in delayed hypersensitivity.

The relationship between the intensity of the delayed hypersensitivity reaction and the dose of antigen used for its elicitation change with time after sensitization. At three weeks the reactions to 100 mug of egg albumen were little different from those to 1 mug but at 14 weeks 100 mug gave much stronger reactions. This means that to follow the development of a delayed hypersensitivity response several antigen doses should be used. If two skin tests were performed simultaneously in the same individual, the stronger one suppressed the weaker one, regardless of whether two different doses of the same antigen or two different antigens were used. Consequently, not more than one skin test at a time should be performed.