Pathogenic role of antibodies against monomeric C-reactive protein in tubulointerstitial nephritis and uveitis syndrome

Antibodies against monomeric C-reactive protein, which is a target antigen expressed both in kidney tubules and uveal cells, have been recently detected in patients with active tubulointerstitial nephritis and uveitis syndrome. We report the case of an 65-year-old woman with acute renal failure caused by biopsy-proven tubulointerstitial nephritis and the onset of uveitis 21 months later. The expression of monomeric C-reactive protein in kidney oligobiopsy was confirmed by immunohistochemical staining using mouse monoclonal antibody against human monomeric C-reactive protein. The levels of antibodies against monomeric C-reactive protein were 117% of the reference during the flare and 22% during the remission of the disease. The difference in the levels of antibodies against monomeric C-reactive protein during flare and remission, and above all positive biopsy staining, supports their pathogenic role in this disease.