Transient reductions | Diurnal variation in normal donors, reciprocating serum cortisol26 |
| Physiological stress (for example, post operative, immediately after exercise,27 or during bereavement)28 |
| Exogenous steroids |
| Cytotoxic drugs |
| Intercurrent infections (for example, urinary tract infection and influenza) |
Transient increases | Women in follicular phase of the menstrual cycle29 |
Long term reductions | Systemic lupus erythematosus (possibly because of apoptosis30) |
| Sarcoidosis (margination into tissues31) |
| Primary immunodeficiencies |
Long term increases | Smoking29 |