Chronic dialysis patients with end stage renal disease have an increased mortality rate as compared to the age matched healthy population. It is known that chronic inflammation contributes to the high incidence of cardiovascular events in chronic dialysis patients. Dialyzers made by membranes with increased pore size (high cut-off Dialyzer HCO1100) may be beneficial in the elimination of inflammatory mediators and may improve the inflammatory status. Hypothesis: In this study it will be investigated whether the treatment with HCO1100 will improve the inflammatory status of chronic dialysis patients.

Inclusion Criteria:

• Dialysis treatment for ≥ 3 months
• Dialysis 3x weekly
• Vascular access by fistula or CVC providing QB of ≥ 250 ml/min
• Dialysis with high-flux dialyzer for a minimum of 2 weeks before begin of study
• CRP > 5mg/L at least once within 12 weeks before inclusion
• Age > 18 and < 99 Years
• Ability to give written informed consent

Exclusion Criteria:

• Missing informed consent form
• Clinically manifested infection or current CRP-value > 50mg/L
• Serum albumin < 35g/L
• Intake of immune suppressive medication
• Pregnancy or lactation
• Participation in a different study