*4.8. Statistics*

Data are presented as median with interquartile range (IQR) or mean with standard deviation when normally distributed. Differences between the study groups were analyzed using Kruskal–Wallis test followed by a post-hoc Dunn's test or a two-way ANOVA test followed by Dunnett's multiple comparison test, where appropriate. GraphPad Prism software (V.7.01, La Jolla, CA, USA) was used for statistical analysis. *p*-values < 0.05 were considered statistically significant.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1422-0067/21/16/5713/s1. Figure S1: Intranuclear staining of Aire protein in cultured human LNSCs; Figure S2: Expression of RRAD and GAD1 stratified according to ACPA status; Figure S3: Induction of IFNGR1 after stimulation with IFNγ in human LNSCs; Table S1: Primers used in this study.

**Author Contributions:** Conceptualization, D.M.G., P.P.T. and L.G.M.v.B.; methodology, J.S.H., R.N., T.A.d.J. and J.F.S.; validation, J.S.H., R.N. and L.G.M.v.B.; formal analysis, J.S.H., R.N. and T.A.d.J.; data curation, J.S.H., R.N., T.A.d.J. and J.F.S.; writing—original draft preparation, J.S.H. and R.N.; writing—review and editing, J.S.H., R.N., T.A.d.J., J.F.S., E.B.M.R., M.S., K.P.v.L., M.M., R.E.M., H.W., A.I.C. and L.G.M.v.B.; supervision, R.E.M. and L.G.M.v.B.; funding acquisition, R.E.M. and L.G.M.v.B.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Innovative Medicines Initiative European Union IMI EU funded project BeTheCure (nr115142), FP7 HEALTH program under the grant agreement FP7-HEALTH-F2-2012-305549 (Euro-TEAM), Dutch Arthritis Foundation grant 11-1-308 and 14-2-403 and The Netherlands Organisation for Health Research and Development (ZonMw) Veni project 91612109 and VIDI project 91718371.

**Acknowledgments:** We thank the study participants in the study, the radiology department at the AMC for LN sampling, F.J. Bemelman (department of Nephrology, AMC) for the collection of LNs from renal transplantation patients, the flow cytometry facility at the Haematology department at AMC especially J.A. Dobber and the AMC Rheumatology department, especially M.J.H. de Hair and M. Safy for patient recruitment, G. Rikken and D. Drop for sample processing and Y. de Wit for western blot experiment. We thank V. Malmström and L. Klareskog for the design and production of the antibodies used in this study and M. Engström and V. Balasingh of the Karolinska Institutet for their help with experiments and interpretation of data.

**Conflicts of Interest:** The authors declare no conflict of interest.
