At-RA treatment decreases anti-GBM abs production and deposition along GBM. A) Serum levels of circulating anti-GBM Abs in all experimental groups measured by ELISA. Results were expressed as percentage of binding relative to samples from positive control serum and presented as Mean ± SD;* P < 0.001 vs. vehicle group and °P < 0.001 vs. HgCl2 group. B) Glomerular deposits of IgG measured by direct immunofluorescence in kidney cryosections from HgCl2-injected rats (a), HgCl2-injected rats also treated with at-RA (b), rats treated only with at-RA (c) and injected with vehicle (d). Ig G fluorescence intensity quantification is shown on the right. Data are presented as mean ± SD; *P < 0.001 vs. vehicle group and °P < 0.001 vs. HgCl2 group.