The interrelationship between the hypothalamic-pituitary-adrenal axis and the immune system has been becoming clear. However, most research about this interrelationship has been performed by in vitro experiments and by using animal models. To know the effect of
hypercortisolism on human immune systems in vivo, we report at 32-year-old man with typical
Cushing disease whose specific and non-specific immunological functions were estimated before and after successful transsphenoidal surgery. We made a diagnosis of
Cushing disease with
dexamethasone suppression test, CRF stimulation test, venous sampling, and MRI scan. Before transsphenoidal surgery, both plasma
ACTH (100pg/ml) and urinary free
cortisol (567 micrograms/day) were higher than the normal range, and the parameters of specific (CD4/CD8 ratio, serum Ig A, PHA/Con-A induced T cell blast formation, and NK cell activity) and non-specific (neutrophil phagocytosis and bactericidal function) immunological functions were clearly impaired. However, at 6 weeks and 6 months after the
tumor excision when hormonal abnormalities were changed to normal, every impaired immunological function was improved to the normal range. These data suggest that impaired specific and non-specific immunological functions were induced by hyercortisolism not only in vitro but also in vivo (a state of
Cushing disease).