When TNF-α production by monocytes from untreated patients with RA, who were age-matched with healthy controls, was analysed, monocytes from untreated patients produced significantly less TNF-α in a T cell-dependent manner (635 ± 210 pg/ml, n = 6) than those from controls (1,648 ± 398 pg/ml, n = 6, P = 0.048). Here, TNF is linked to rheumatoid arthritis.