Studies on adrenocortical eosinopenia: a clinical and statistical evaluation of four-hour eosinophil response test.

As early as 1914 Schwarz (1) suspected an inverse relationship between adrenal activity and the level of circulating eosinophils. Twenty-five years later Dalton and Selye (2) noted eosinopenia following stress in animals and related it to release of adrenal cortical hormones. More recently Thorn and his associates (3, 4) observed a prompt decrease in circulating eosinophils in healthy persons, and in patients, following a single injection of pituitary adrenocorticotropic hormone (A.C.T.H. or corticotropin). The greatest reduction in eosinophils was seen four hours after injection and was related to secretary activity of the adrenal cortex. In a study of 40 people with normal adrenal activity Thorn, Forsham, Prunty, and Hills (5) reported that the mean drop in circulating eosinophils at four hours was 70%o below preinjection levels. In all instances the drop in circulating eosinophils was greater than 45%o. This was in sharp contrast to what was seen in patients with Addison's disease, where they noted little change in circulating eosinophils after injection of corticotropin. Thorn, therefore, proposed that the eosinophil response to A.C.T.H. should be used as a test in the diagnosis of Addison's disease. He and Forsham suggested (6) that a fourhour post-injection ". . . fall of 50%o or more of the circulating eosinophils eliminates the diagnosis of adrenal cortical insufficiency," and they indicated that an inadequate response, of less than 50%o fall, may represent true adrenal cortical insufficiency. A transitory eosinopenia also develops in animals after injection of epinephrine. On the basis