Acknowledgement
We are grateful to Dr Maki Shibamoto-Iwatani (Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine/Department of Rheumatology, Kakogawa Central City Hospital) for helpful discussion.
Disclosure statement
KM has received consulting fees, lecture fees, and/or honoraria from Bristol-Myers Squibb, and research grants from Asahi Kasei Pharma and Astellas Pharma. All other authors declare no conflicts of interest.