Fig. 6: Cell-based assays for detection and functional characterization of anti-C-C motif chemokine receptor 8 autoantibodies.

A Representative histograms from flow cytometry showing binding of anti-C-C motif chemokine receptor 8 (CCR8)-positive IgG from systemic sclerosis (SSc) patients or healthy controls (HC) to CCR8-overexpressing HEK293 cells. A fluorophore-conjugated anti-human IgG Fc antibody was used for detection. B Quantification of mean fluorescence intensity (MFI) in CCR8-overexpressing cells incubated with anti-CCR8-positive or control IgG, with or without preincubation with blocking anti-CCR8 monoclonal antibody (n = 4 technical replicates per group). C ERK phosphorylation levels in CCR8-overexpressing HEK293 cells after stimulation with CCL1 in the presence of anti-CCR8-positive or control IgG, as measured by ELISA (n = 8 biological replicates per group). D Treg migration assay in Transwell culture systems. The number of migrated Tregs in response to CCL1 with anti-CCR8-positive IgG or control IgG (n = 6 biological replicates per group) are presented. Statistical significance was assessed using Welch’s ANOVA with Dunnett’s T3 multiple comparison adjustment. Error bars are defined as the standard error of the mean. Source data are provided as a Source Data file.