Fig. 1

Antibodies to 3S-P in serum samples from patients and healthy control subjects. a ELISA results of detection of anti-3S-P IgG in the subjects’ sera. Each circle represents one patient. b Sensitivity and specificity of the assay of IgG antibodies against 3S-P for differentiating between patients with sSS and control subjects. The ROC curve indicates the level of antibodies against 3S-P in patients with sSS compared with that in patients with RA, pSS, or SLE. sSS Secondary Sjögren’s syndrome associated with rheumatoid arthritis, RA Rheumatoid arthritis, pSS Primary Sjögren’s syndrome, SLE Systemic lupus erythematosus, AS Ankylosing spondylitis, HC Healthy control subjects, 3S-P Secondary Sjögren’s syndrome-associated peptide, IgG Immunoglobulin G