Dermal Sensitivity to Different Doses of Spherulin and Coccidioidin

Abstract

Spherulin, a new reagent, was compared with coccidioidin for eliciting delayed dermal hypersensitivity in 298 human subjects living in an area endemic for Coccidioides immitis. As standard (dilute) doses, spherulin detected 32 percent more reactors than coccidioidin. A tenfold higher concentration of spherulin showed a 50 percent higher reactor ratio than did a tenfold higher dose of coccidioidin in subjects nonreactive to the standard dose of either reagent Severe local reactions were encountered in only one subject; these reactions were produced by the low doses of both coccidioidin and spherulin. Evidence is presented that latent sensitivity to coccidioidin can be made apparent by a reaction to spherulin.