- Design
- Single-centre retrospective observational study
- Population
- 112 children and young people tested for anti-adalimumab antibodies (of 390 treated)
- Primary outcome
- Anti-adalimumab antibody positivity and clinical correlates
- Effect
- 41.0% positive; 52.4% without DMARD vs 21.1% with full-dose methotrexate (OR 4.12)
A UK paediatric rheumatology service reviewed 112 children and young people tested for anti-adalimumab antibodies while treated for juvenile idiopathic arthritis or non-infectious uveitis between 2015 and 2024, out of 390 receiving the drug. Most were tested during a flare.
Of those tested, 41.0% were antibody positive. Every child with a subtherapeutic drug level was positive. Positivity was 52.4% without a concurrent disease-modifying drug against 21.1% with full-dose methotrexate (OR 4.12). Antibody-positive children stopped adalimumab more often (53.1% vs 15.2%). On repeat testing, antibody levels fluctuated, including falls after corticosteroids.
Because testing was done mainly in flares, 41% overstates the rate across all treated children. The study is single-centre and observational.
For uveitis clinics sharing care with rheumatology, the findings support keeping methotrexate alongside adalimumab where tolerated and repeating antibody and drug-level tests before abandoning a biologic that was working.
- Check adalimumab drug level and antibodies when a child with uveitis flares on treatment.
- Repeat an isolated positive antibody result before switching biologic.
- Keep concurrent methotrexate at full dose where tolerated.
- Coordinate testing and decisions with paediatric rheumatology.
Why it matters
A single antibody result can prompt an unnecessary switch away from the one biologic with strong evidence in paediatric uveitis.
Don't overread it
This retrospective study tested mainly during flares, so it overestimates how common antibodies are overall.
The statistics, in plain English
An odds ratio of 4.12 means the odds of antibodies were about four times higher without methotrexate. Because those tested were mostly in flare, the 41% rate is likely higher than in all children on adalimumab.
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