Experimental autoimmune cystitis: further characterization and serum autoantibodies

Previously, we described an animal model for interstitial cystitis (IC), ex perimental autoimmune cystitis (EAC) [Luber-Narod et al. Urol Res 24:367]. Further characterization of animals with EAC indicates that peak and mean u rinary frequency are elevated compared with sham-injected controls and that the disease progresses with at least two cycles of exacerbations and remis sions. We had shown evidence suggesting EAC to be autoimmune in nature. In this paper, we identify serum autoantibodies from 9/10 EAC animals which bi nd to a protein specific to rat bladder with a relative molecular weight of 12-kDa. Such autoantibodies are absent in 12/13 normal and sham-injected a nimals as well as animals which fail to develop EAC despite disease inducti on. These findings suggest that EAC is a reproducible model of cyclical inc reases of urinary frequency, and that a 12-kDa antigen is the target of aut oantibodies which correlate with those elevations. Identification of this t arget antigen may explain the pathogenesis of increased urinary frequency i n these animals and potentially in IC as well.