Šumová B, et al. - In patients with incomplete systemic lupus erythematosus (iSLE), in those with established SLE, and in healthy controls (HCs) experts evaluated the plasma levels of S100A4, S100A8/9 and S100A12 to gauge the possible value of the S100 proteins as diagnostic or activity-specific biomarkers in SLE. In a cross-sectional cohort study of 44 patients with SLE, 8 patients with iSLE, and 43 HCs, plasma levels were measured by enzyme-linked immunosorbent assay. Patients with high and low disease activity were not differentiated by S100 levels. They noted the significant association of only the S100A12 levels with SLEDAI-2K and with cSLEDAI-2K. In SLE patients, S100 proteins were significantly higher vs HCs. S100A4 especially could have value as a diagnostic biomarker for SLE.