Stress-responsive neurohormonal systems are involved in major depressi
on (MD) and panic disorder (PD). The immune system, which is closely c
onnected with neuronal and hormonal systems, has been studied in MD: a
systemic immune activation has been recently reported. To determine w
hether similar changes in the immune function are present also in PD,
we studied leukocyte enumeration by flow cytometry in conjunction with
monoclonal antibody staining, in 18 PD, 23 MD in drug-free conditions
and 20 controls. We found a significantly higher percentage of HLADR(p<0.001) and of CD19 cells (p<0.01) in PD and MD and a lower percenta
ge of CD3 (p<0.05) in PD. Urinary free cortisol levels were higher in
MD compared to PD. A pattern of lymphocyte subpopulation distribution
compatible with an activation of the immune system was found in MD and
PD. This activation was present also with high glucocorticoid levels,
suggesting a possible defect of glucocorticoid receptors.