Anti-tumour necrosis factor (TNF) α treatment has had a tremendous effect on the managment of rheumatoid arthritis, but it needs to be monitored closely. Guidelines state that haematological complications are rare, so regular full blood counts are not recommended.^1,2 We noticed that a minority of our patients with rheumatoid arthritis receiving anti-TNF treatment developed neutropenia (<2×10⁹/l). Table 1 summarises the demographics of 133 patients with rheumatoid arthritis. Of these, 14.3% of patients had at least one episode of neutropenia, with no obvious cause other than the anti-TNF treatment. The lowest neutropenic episodes had counts that ranged from 1.02 to 1.94 (8/19 patients had an episode with counts <1.5). The time period …