TNF and ankylosing spondylitis: Clinical data included: (i) age, disease duration, gender, human leukocyte antigen (HLA) B27 status, clinical presentation over disease history considering both the axial involvement and the presence of peripheral arthritis, dactylitis or entheseal pain; (ii) disease activity as assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and DAS28; (iii) functional status as assessed by the Bath Ankylosing Spondylitis Functional Index (BASFI) and HAQ; (iv) pharmacological therapy as specific tumor necrosis factor-α inhibitor (TNFi), comedication with DMARDs.