Histoplasmin Sensitivity

IN A STUDY of children in Tennessee in 1942 Gass and his associates1observed that many children exhibiting negative reactions in tuberculin tests had pulmonary calcifications. Later, Christie2reported the same observation and began a search for a condition other than tuberculosis as a cause of these lesions. On the basis of reports that in the western states coccidioidomycosis caused pulmonary calcifications, he tested the reactions in his patients to various fungous antigens. Although none of the children gave strongly positive reactions to coccidioidin, many gave positive reactions to histoplasmin, an antigen made from Histoplasma capsulatum. The purposes of this study were to determine the percentage among the school children in an Alabama city who gave positive reactions to histoplasmin and to tuberculin, and also to study the roentgenograms of those with positive reactions in the tests. Of 1,200 Negro children in grammar school in a crowded area