Subclinical hypercortisolism among polycythemia vera patients

Abstract

Background JAK2V617F, a somatic gain-of-function mutation involving the JAK2 tyrosine kinase gene, occurs in nearly all patients with polycythemia vera (PV). JAK2 is also essential in hypothalamo-pituitary- adrenal (HPA) axis system which is known to play a role in subsequent steroid secretion. The purpose of this study was to determine whether or not PV induces subclinical hypercortisolism (SH). Design Cross-sectional study. In order to compare the prevalence of SH in PV and matched control individuals, we performed a case-controlled study, enrolling 31 PV and 20 age- and body mass index-matched patients. Methods and Results Adrenal endocrine function was assessed in a cohort of 31 patients with PV. Baseline serum cortisol levels and 2-day 2 mg DST (dexamethasone suppression test, 0.5 mg dexamethasone orally every 6 hours for two days) showed a trend for higher serum cortisol levels in PV patients than in control subjects. Among the 31 patients, 6 had biological abnormality of the hypothalamic-pituitary-adrenal axis and were diagnosed as subclinical hypercortisolism. None of the subjects in the control group exhibited cortisol responses to DST higher than 50 nmol/L. Discussion In conclusion, a relatively high prevalence of hypercortisolism was found in PV patients. As these observations were in a small cohort of PV, further studies are needed to evaluate HPA axis in PV patients. © 2010 The Japanese Society of Internal Medicine.