Chemotaxis of T cells induced by immunoglobulin G from systemic sclerosis patients is reduced by receptor antagonists and depends on autoantibody levels. (A) Number of T cells that migrated toward medium control (contr.), immunoglobulin G of healthy donors (HD-IgG) and systemic sclerosis patients (SSc-IgG). Chemotaxis induced by SSc-IgG was significantly reduced by the angiotensin II receptor type 1 (AT1R) antagonist valsartan (Val) and the endothelin receptor type A (ETAR) antagonist sitaxsentan (Sit). Chemotaxis induced by HD-IgG was not significantly reduced (n.s.). (B) Numbers of T cells that migrated toward SSc-IgG correlate with anti-AT1R Aab levels of the SSc-IgG fractions used. (C) Numbers of T cells that migrated toward SSc-IgG correlate with anti-ETAR Aab levels of the SSc-IgG fractions used. Data are derived from five independent migration assays done with a total of 13 SSc-IgG and 10 HD-IgG. Statistical analysis was done by Mann–Whitney U test (control vs. HD-IgG, control vs. SSc-IgG and HD-IgG vs. SSc-IgG), Wilcoxon matched-pairs test (IgG vs. IgG with antagonist) and Spearman's correlation (B and C). Mean +/- SEM are shown in (A). *P < 0.05.