Xanthogranulomatous pyelonephritis is associated with higher tissue expression of monocyte chemotactic protein-1.

TOPIC: Xanthogranulomatous pyelonephritis (XGP) is a chronic inflammation of the kidney characterized by destruction and replacement of its parenchyma with granulomatous tissue. It is associated with both chronic urinary obstruction and urinary tract infection (UTI).

METHODS

We studied two children with chronic ureteropelvic junction obstruction (UPJO) and recurrent UTI nephrectomized for poor kidney function. An intraoperative renal biopsy was taken to relate the presence of infiltrating monocytes plus tubular atrophy to tissue expression of monocyte chemotactic protein-1 (MCP-1) and epidermal growth factor (EGF). XGP was diagnosed by a pathologist in both cases.

RESULTS

MCP-1 expression was significantly higher in the two patients compared with the controls or patients with uncomplicated UPJO. It also correlated with the extent of monocyte infiltration, whereas EGF was only significantly downregulated when compared with the controls.

CONCLUSIONS

MCP-1 would seem to play a key role in the pathogenesis of XGP by mediating the recruitment of circulating monocytes or by cells resident in the interstitial space.