Dialysate cytokine levels do not predict encapsulating peritoneal sclerosis

Abstract

Background: Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of long-term peritoneal dialysis (PD). There is no well-validated method for predicting which patients will develop the condition, although known risk factors include long duration of PD, high glucose exposure and lack of residual renal function. We have investigated whether dialysate cytokines (MCP-1 (monocyte chemotactic protein-1), CCL18 (pulmonary and activation-regulated cytokine, PARC), IL-6 (interleukin-6), CCL15 (leukotactin) and angiogenin) could be used to predict the onset of EPS more effectively than known clinical risk factors.

Methods: Samples of dialysate and clinical data were prospectively collected from 151 patients at the West London Renal center between 2003 and 2010. Dialysate cytokine levels were measured using the enzyme-linked immunoabsorbant assay (ELISA) technique. Encapsulating peritoneal sclerosis subsequently developed in 17 patients during a follow-up period of 27 - 113 months. Cytokines found at higher levels in dialysate of pre-EPS patients were investigated as candidate predictors of EPS using logistic regression analysis.

Results: Dialysate IL-6, MCP-1 and CCL15 were significantly higher in patients who subsequently developed EPS; however, a logistic regression model using dialysate cytokines to predict EPS was no better than a model using well-recognized clinical markers (length of time on PD and membrane transport status).

Conclusions: Although MCP-1, IL-6 and CCL15 were found at higher levels in the dialysate of patients who subsequently developed EPS, dialysate levels of these cytokines do not improve prediction of future EPS above a model using known clinical risk factors.

Keywords: Cytokines; encapsulating peritoneal sclerosis; screening.

Figure 1 —

The four-hour dialysate quantity of MCP-1 correlates with D/P creatinine. Similar correlations were seen for all cytokines studied. MCP-1 = monocyte chemotactic protein-1; D/P creatinine = dialysate to plasma creatinine ratio.

Figure 2 —

Clinical features of the EPS patients and of the cohort matched for PD duration. EPS = encapsulating peritoneal sclerosis; PD = peritoneal dialysis; D/P creatinine = dialysate to plasma creatinine ratio; GFR = glomerular filtration rate.

Figure 3 —

Dialysate cytokine levels in the EPS patients and in the cohort matched for PD duration. EPS = encapsulating peritoneal sclerosis; MCP-1 = monocyte chemotactic protein-1; IL-6 = interleukin-6; CCL15 = leukotactin; CCL18 = pulmonary and activation-regulated cytokine, PARC; PD = peritoneal dialysis.

Figure 4 —

ROC (receiver operating characteristic) curve to illustrate the logistic regression analysis. The predictors of EPS are duration of PD and D/P creatinine. The area under the curve is 0.886. EPS = encapsulating peritoneal sclerosis; PD = peritoneal dialysis; D/P creatinine = dialysate to plasma creatinine ratio.

Figure 5 —

ROC (receiver operating characteristic) curve to illustrate the logistic regression analysis. The predictor of EPS is dialysate quantity of MCP-1. The area under the curve is 0.78. EPS = encapsulating peritoneal sclerosis; MCP-1 = monocyte chemotactic protein-1.