Footnotes

• Contributors PCR, MAB: conceived study; contributed patients/materials; contributed to or performed analysis. M-EC, PL, AC, DE: contributed to or performed analysis; wrote/reviewed/edited the paper. LAB, KH, SL, KBJ, S-CS, MW, MW, XZ, H-JG, GC, JN, BAL, ØF, JT, KL, LJ, YL, XW, DE, RB-V, LSG, SS, NH, JM, JLF-S, MAG-G, CL-L, PB, KG, JSHG, DDG, PR, WPM, HX, IEvdH-B, C-TC, RV-O, CR-S, IMH, FMP-S, RDI, JM, MB, JDR, T-HK, BPW: contributed patients/materials; wrote/reviewed/edited the paper.

• Funding PR is funded by the RACP-ARA-Starr Research Fellowship. MAB is a National Health and Medical Research Council Senior Principle Research Fellow. This work was in part funded by grants from Arthritis Research UK (19536 & 18797), the NIHR Oxford Comprehensive Biomedical Research Centre (immunity and inflammation theme A93081), NIHR Thames Valley collaborative research network and National Ankylosing Spondylitis Society (UK) and NIH/NIAMS—P01-AR052915.

• Competing interests None declared.

• Ethics approval UQ Human Ethics and Metro South Ethics Committee.

• Provenance and peer review Not commissioned; externally peer reviewed.

• Data sharing statement The data that the study uses have been fully detailed elsewhere.1