Patients had high disease activity at baseline, which reduced rapidly after start of TNF-α blocking therapy and stabilized during follow up (mean Bath ankylosing spondylitis disease activity index (BASDAI) was 3.0 ± 2.1, mean ankylosing spondylitis disease activity score (ASDAS) 2.0 ± 0.9, and median C-reactive protein (CRP) 3 (IQR 2–7) at 4 years). Here, TNF is linked to ankylosing spondylitis.