Sensitivity to hydrocortisone is a relevant factor in the immunoendocrine relationship: I. The cell-mediated immune response in relation to blood levels and in vitro immunosuppressive effects of hydrocortisone in patients with asthma and healthy control subjects

The role of endogenous hydrocortisone in the regulation of lymphocyte activity was assayed in patients with asthma (patients with chronic nonspecific lung disease, characterized by attacks of dypsnea, alternating with symptom-free periods) and healthy control subjects. After priming, delayed-type hypersensitivity skin reactions were induced with Helix pomatia hemocyanin (HPH). Hydrocortisone blood levels were measured. The effect of hydrocortisone on HPH-induced lymphocyte proliferation was determined in vitro. The results demonstrate that hydrocortisone in low concentrations (100 ng/ml) inhibited in vitro lymphocyte proliferation equally in patients and control subjects. However, both groups demonstrated a large interindividual variation in hydrocortisone sensitivity. Therefore, in order to determine the immunologic effect of hydrocortisone blood levels in vivo, a hydrocortisone suppression index (HSI) was calculated by use of the information on hydrocortisone concentrations in vivo and the biologic effect of hydrocortisone in vitro. This HSI appeared to be inversely related with the in vivo cell-mediated immune response to HPH. This was reflected in an inverse correlation between HSI and delayed-type hypersensitivity skin reactions to HPH, both in patients (R = −0.64), in control subjects (R = −0.69), and in the total group (R = −0.68; p < 0.001). No differences were observed between patients and control subjects. It is concluded that endogenous hydrocortisone is likely to play an important role in the regulation of lymphocyte activity in patients with asthma and healthy control subjects. This may have important consequences for the clinical expression of asthmatic symptoms, since the role of lymphocyte activity in the pathogenesis of asthma is increasingly recognized.