GNS and FLNA protein concentrations were measured in serum and SF samples from patients with RA, serum samples from patients with CTD, SpA, or LA, and serum samples from HCs. (A) GNS protein concentrations and (B) FLNA protein concentrations are shown, as measured by ELISA assay. For both analyses, positivity was defined as greater than 3 SD above the mean value for HC subjects (area above the shaded region). Symbols represent values for individual patients, and horizontal lines indicate the mean values. The values for patient RA1 are indicated with a star. Only significant P values, determined by unpaired, 2-tailed t test with Welch’s correction, are shown. SLE, systemic lupus erythematosus.