Table 2

Factors affecting CD4 counts

Transient reductionsDiurnal 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 increasesWomen in follicular phase of the menstrual cycle29
Long term reductionsSystemic lupus erythematosus (possibly because of apoptosis30)
Sarcoidosis (margination into tissues31)
Primary immunodeficiencies
Long term increasesSmoking29