FIGURE 5.

Anti-vimentin autoantibodies, HLA-DRβ1*15 biases, and discordance between two autoantibody responses in IPF patients. (A) Incubation of IPF PBMC cultures with native vimentin (Vim; 1 μg/ml) and without (Medium) increased levels of anti-vimentin autoantibodies; these responses were blunted by prior addition of F(ab′)₂ anti-human HLA-DR (2 μg/ml). (B) Plasma levels of anti-vimentin IgG autoantibodies were greatest among IPF patients in each cohort. Horizontal lines and numbers denote median values. (C) Anti-vimentin autoantibody concentrations were lower among the IPF patients who were positive for HLA-DRβ1*15 at UAB and U. Pitt. (see also Supplemental Table I). (D) There were no apparent correlations between autoantibody responses to vimentin and HSP70 among the IPF subjects (U. Pitt.) who had received equal measures of each. *p < 0.01, **p < 0.001.