Hj. Guth et al., The measurement of cytokine production capacity during dialysis - a new dynamic method for the evaluation of biocompatibility?, INT J ARTIF, 23(10), 2000, pp. 675-679
The activation of monocytes and other immunocompetent cells during hemodial
ysis can be attributed to their contact with immunogenic structures such as
membranes, blood lines, and endotoxins. The simple measurement of cytokine
s in blood cannot completely describe the whole dimension of this event. St
imulation of monocytes and other immunocompetent cells in whole blood with
lipopolysaccharides (LPS) for IL-6 and phytohemagglutinine (PHA) for TNF at
the start and end of dialysis may make it possible to better analyze cellu
lar response during dialysis. Ten healthy volunteers and 10 patients suffer
ing from chronic renal failure were tested with the commercial whole-blood
stimulation assays "Dynamix"-IL-6-DIA and -TNF-alpha-DIA (Biosource Diagnos
tics, Ratingen, Germany). Then 24 patients undergoing hemodialysis with hem
ophane (n=12) and polyamide (n=12) membranes were examined before and after
dialysis treatment. The unpaired Wilcoxon t- test was used for statistical
analysis. Healthy volunteers and patients with chronic renal failure showe
d no statistical differences in concentrations of TNF-alpha and IL-6 before
or after whole blood stimulation (WBS). In comparison to patients with chr
onic renal failure, pre-WBS concentrations of both cytokines (p<0.034) were
increased in patients of each membrane group before dialysis. After whole
blood stimulation, no differences were observed At the end of dialysis trea
tment, the pre- and post-WBS IL-6 values were both significantly higher in
the hemophane group (p=0.049 and p=0.0038, respectively) TNF-alpha concentr
ations were unchanged. No significant differences in the polyamide group we
re found between the start and end of treatment for either cytokine. A comp
arison of these membrane groups showed that only the pre-WBS IL-6 concentra
tion in the hemophane group was elevated (p=0.022) after dialysis. In concl
usion, the presence of uremia alone could not influence the cytokine produc
tion and release capacity. In our patients, dialysis elevated pre-WBS conce
ntrations of TNF-alpha and IL-6, and increased IL-6 release from immunocomp
etent cells after whole blood stimulation in the hemophane group. The use o
f polyamide membranes decreased the action of monocytes and other immunocom
petent cells, but could not completely prevent this phenomenon. The whole b
lood stimulation assays for measurement of TNF-alpha and IL-6 may represent
a new, dynamic method for evaluating biocompatibility.