The evaluation of the eosinopenic response to corticotrophin and cortisone in the newborn infant.

The eosinopenic response to stress has been recognized since Zappert (1893) described its occurrence m certain infections, and in recent years it has been included among the phenomena of the alarm reaction (Selye, 1949). It was also shown that a decrease in the number of circulating eosinophils followed the injection of corticotrophin or cortisone, and Hills, Forsham and Finch (1948) concluded that sts induced eosinopenia by the release of these hormones. Thorn, Forsham, Prunty and Hills (1948) demonstrated that the secretion of the adrenal cortex was essential if eosinopenia were to be produced, and from this devised the Thorn test. Following the determination of the absolute eosinophil count an adult receives 25 mg. of corticotrophin and the percentage decrease in four hours is found. Thorn et al. believed that a decrement of 50% or more should occur in the presence of healthy adrenal cortex. The si nce of the results is dependent upon the stability of the eosinophil count in normal people over a similar time interval, and it has been shown by Swanson, Bauer and Ropes (1952) from a review of the literature and from a small but carefully studied series of their own that spontaneous vanations of this magnitude may in fact occur at certain periods of the 24 hours in adults. The test has been employed also in newborn infants, but no careful study of hourly changes in the absolute eosinophil level at that age can be found. It was decided, therefore, to undertake an evaluation of the test in the neonatal period by determining the nature of the spontaneous variation over a four-hour interval and to note any relationship that might exist between eosinophil change and disturbance of the baby. The second part of the investigation was planned to determine what responses could be obtained by the injection of varying doses of corticotrophin and cortisone. Finally it was hoped to determine whether the magnitude of the response varied with the age of the infant.