Biocompatibility of hemodialysis membranes: Interrelations between plasma complement and cytokine levels

Hemodialysis (HID) membrane biocompatibility is defined as absence of compl ement activation. We have recently shown that circulating levels of interle ukin (IL) 1 and IL-2 predict death and survival, respectively, of HID patie nts. Studies have assessed IL-1 in treatments with biocompatible and less b iocompatible dialysis membranes, but no study has correlated circulating le vels of all these immunoreactants. We assessed these immunoreactants, and t emperature as an outcome, during HID in patients treated with different mem branes. Twelve stable patients, receiving thrice-weekly chronic bicarbonate HID, were randomly dialyzed with three different types of membranes, compo sed of: Cuprophan, cuprammonium rayon modified cellulose, and Hemophan. Blo od was drawn from the arterial line port before (Pre) and 15, 30, and 60 mi n during and after (Post) HID. Patients' temperatures were measured before and after each treatment. The plasma concentrations of IL-1 and IL-2 and fa ctors C3a and C5a were assessed by ELISA. There were no differences between baseline levels of any of the immunoreactants in patients treated with dif ferent dialyzers. C3a, C5a, and IL-1 levels increased significantly during HID treatments with all three different membranes. C3a, C5a, and IL-1 level s during Cuprophan and Hemophan treatments were significantly higher than t he levels during modified cellulose treatment at 30 and 60 min and Post (p < 0.01). For all the immunoreactants, however, the Post levels were higher than the Pre levels. In contrast to IL-1, there were no differences in mean IL-2 levels during treatments when different membranes were compared. Ther e were few correlations of plasma C3a and C5a levels with plasma IL-1 level s, but there was only one treatment time in one dialyzer group during which IL-2 and any of the other factors were correlated. Pre and Post temperatur e values and percent change in temperature were not correlated with any of the immunoreactants measured. These data show that C3a, C5a, and IL-1 respo nses are similar, but not identical, during treatments with different membr anes. The response of circulating IL-2 levels to treatments is quite differ ent from that of plasma C3a, C5a and IL-1 levels and suggests that these ch anges are not solely due to treatment factors. Treatment with modified cell ulose membranes is associated with a different immunoreactive profile as co mpared with patients dialyzed using other cellulose membranes. We suggest t hat circulating IL-1 levels are good biocompatibility markers. Copyright (C ) 2001 S. Karger AG, Basel.