Inflammation

Similarities to systemic lupus and other autoimmune disorders; chronic inflammation in pathology; some responses to steroids, NSAIDS, and immunosuppressants; positive FANA at times; Ig deposits in bladder

Ig deposits nonspecific in origin; inflammation in bladder frequently not present; phenotypes of inflammatory cells in bladder; variable response to immunosuppressant therapy; relief on diversion

Immune mediators; immunecell typing; specific antibody levels

Deficiencies in bladder lining

''Leaky'' epithelium in IC, also produced in normal subjects by protamine and reversed by heparin; decreased GAG excretion in IC patients; increased GAG produced by hydro-distention; ultrastructure shows loose urothelium

GAG treatment not always effective; deficiency never demonstrated directly

Decreased GAG in urine; altered GAG on umbrella cells

Toxic substances in urine

Diversion relieves symptoms; increased serum anti-THP IgG; cytotoxic urine

Some evidence suggests defect is from inside bladder

Antibodies vs. urinary constituents