IDO1 and systemic lupus erythematosus: There were no significant differences in follicular and interfollicular amounts of IDO1+ cells or PD-L2+ cells when patients with RA; RA and/or SLE; RA and/or Sjögren’s syndrome; or RA, SLE and/or Sjögren’s syndrome were grouped and compared to patients with other AD using Fischer ́s exact test (supplementary Table S1).