Overt Immune Dysfunction after Cushing's Syndrome Remission: A Consecutive Case Series and Review of the Literature

Abstract

Autoimmune diseases frequently improve during active Cushing's syndrome. Several studies have reported new onset or exacerbation of these conditions upon cortisol normalization. Our objective was to investigate the incidence and clinical characteristics of patients with autoimmune or allergic diseases after Cushing's syndrome remission. Consecutive cases of confirmed Cushing's syndrome were characterized. A review of the literature was conducted to identify previous descriptions of immune dysfunction upon remission and evidence of the hypothalamic-pituitary-adrenal axis influence on the immune system. Among 66 patients who achieved Cushing's syndrome remission, the incidence of immune dysfunction was 16.7%, where eight cases (72.7%) were noted for the first time and three (27.3%) were exacerbated. All had an ACTH-dependent cause. Glucocorticoids reduce proinflammatory cytokines and interact with other transcription factors affecting T cell and mast cell survival. Hypercortisolism induces a state of immunosuppression. After Cushing's syndrome remission, rebound immunity frequently results in overt conditions extending beyond thyroid dysfunction.