TNF and juvenile idiopathic arthritis: However, patients with JIA cannot be easily compared with the general population, since both JIA and the extensive pre-treatment with immuno-suppressants, including methotrexate, have been suggested as additional risk factors for lymphoma [36, 37], and a retrospective study of 2000–2014 US claims data did not find an increased risk of malignancies in TNF-treated children with JIA, pediatric inflammatory bowel disease, or pediatric plaque psoriasis [38].