Passive Local Sensitization in Atopic Individuals.

Abstract

The technic for studying the absorption of unaltered proteins in humans has been described. 1 A cutaneous site is passively and locally sensitized with a small amount of serum taken from an atopic patient who is extremely sensitive to the protein to be tested. On the following day, the specific protein is fed to the subject on an empty stomach. Within a few minutes to a few hours, a wheal forms at the sensitized site demonstrating roughly the rapidity and, to a certain degree, the amount of unaltered protein absorption in that subject. The results of studies with various proteins and in different types of subjects have already been presented. 2 , 3

The technic may, however, fail completely or may show diminished reactions in atopic subjects. One of the factors which accounts for this is that atopic individuals do not accept passive local sensitization as well as normals. The evidence is submitted herewith.

The ability of atopics to accept passive local sensitization was determined by titrating on their skins the sensitizing power of certain atopic sera of known strength.

The titrations of these sera were performed according to the method of Coca and Grove 4 . Atopic and normal subjects were sensitized with the serum in a range of dilutions determined to be suitable for that serum by previous titration on normal subjects. Seven days after sensitization the sites were tested with a suitable dilution of the atopen for which the serum in question contained reagins. Control tests on normal skin sites were introduced at the same time. Readings were made according to the method used in the indirect method of testing 5 ; i. e., any definite excess of reaction, either in wheal or in erythema, on the sensitized site over that manifested on the control site was considered a positive transfer.