Inflammation markers, chronic kidney disease, and renal replacement therapy

Chronic kidney disease (CKD) is associated with a proinflammatory state and an excess of cardiovascular risk. In this work, we describe changes in inflammatory markers-C-reactive protein (CRP), pentraxin 3 (PTX3), serum component of amyloid A (SAA), and procalcitonin (PCT)--in CKD patients compared with a control group of subjects with a normal estimated glomerular filtration rate (eGFR). Blood samples were obtained from 69 healthy individuals (GP) and 70 end-stage CKD patients--25 not yet on dialysis, 22 on peritoneal dialysis (PD), and 23 on hemodialysis (HD). These were the results [median (95% confidence interval)] for the GP CKD, PD, and HD groups respectively: CRP: 1.40 mg/L (1.19-2.11 mg/L), 6.50 mg/L (3.57-8.32mg/L), 7.60 mg/L (2.19-22.10mg/L), 9.60 mg/L (6.62-16.38 mg/L). SAA: 3.10 mg/L (2.90-3.53 mg/L), 7.11 mg/L (3.81-15.40mg/L), 9.69 mg/L (5.07-29.47mg/L), 15.90 mg/L (6.80-37.48 mg/L). PCT: 0.03 ng/mL (0.02-0.03 ng/mL), 0.12 ng/mL (0.09-0.16 ng/mL), 0.32 ng/mL (0.20-0.46 ng/ mL), 0.79 ng/mL (0.45-0.99 ng/mL). PTX3: 0.54 ng/mL (0.33-0.62 ng/mL), 0.71 ng/ mL (0.32-1.50 ng/mL), 1.52 ng/mL (0.65-2.13 ng/mL), 1.67 ng/mL (1.05-2.27 ng/mL). Compared with levels in the GP group, levels of SAA and CRP (systemic response) were significantly higher in CKD patients on and not on dialysis. Levels of PTX3 were higher only in dialyzed patients, significantly so in those on HD (greatly different from the CRP levels). These differing levels might be related to a local reaction caused by an invasive intervention (PD or HD). As eGFR declines and with the start of renal replacement therapy, PCT increases. Levels of PCT could potentially cause confusion when these patients are being evaluated for the presence of infection, and may also demonstrate some microvascular implications of dialysis therapy.