CCL18 in peritoneal dialysis patients and encapsulating peritoneal sclerosis

Peritoneal fibrosis manifests clinically as membrane failure or encapsulating peritoneal sclerosis (EPS). There are no clinical or biochemical tests to determine the rate of progression of peritoneal fibrosis. CCL18/pulmonary and activation-regulated chemokine (PARC) is profibrotic and stimulates collagen production independent of the effect of transforming growth factor beta. This has not been studied in peritoneal dialysis (PD) patients.

We have prospectively studied 106 patients, free from infection/recent peritonitis. A high concentration of CCL18 was discovered by multiplex antibody arrays and quantified by ELISA. Serum and dialysate levels were examined for their prognostic values.

By multiple regression analysis, dialysate CCL18 (6·76 ± 0·66 μg 4 h⁻¹) correlated with increasing membrane transport status (TS) (P < 0·0001) and total glucose exposure/24 h (P = 0·033). Serum CCL18 correlated with high TS (P = 0·0001) and duration of PD (P = 0·001). After 12 months of follow-up, 57 patients remained on PD while 12 patients were transferred to haemodialysis (HD) and seven developed EPS. Patients who subsequently developed EPS had higher baseline dialysate CCL18 (11·5 ± 3·6 μg 4 h⁻¹ vs. 5·6 ± 0·82 μg 4 h⁻¹, P = 0·03) and serum CCL18 (156·9 ± 12·8 ng mL⁻¹ vs. 124·8 ± 12·2 ng mL⁻¹, P = 0·02) compared with the stable PD group.

This is the first report of high levels of CCL18 in the spent dialysate and serum from long-term PD patients. These levels correlated with dysfunction of peritoneal membrane transport status, therefore following CCL18 in a longitudinal study may be of interest.