Cell-free plasma DNA during Hemodialysis.

Purpose: Cell-free plasma DNA (cfDNA) levels originating predominantly from apoptotic leukocytes were found to rise during hemodialysis (HD) session, and as such are considered a marker of HD membrane biocompatibility. The purpose of our study was to determine the changes of cfDNA during two consecutive high-flux polysulphone HD sessions after a long (HD-L) and short (HD-S) interdialytic interval.

Methods: A total of 17 HD patients were examined. Prior to HD and at 30 and 240 min, cfDNA (using real-time PCR) and leukocyte count were determined.

Results: No significant difference was found when comparing pre-HD-S with pre-HD-L cfDNA [4893 (1090-28804) vs. 4589 (691-73796) genomic equivalent/mL]. A significant increase in cfDNA at 240 min was seen in HD-L (p < 0.05) but not in HD-S. Leukocyte count correlated with cfDNA levels before HD-S (r = 0.8; p < 0.01); however, no other correlation was seen between routinely measured biochemical markers and pre-HD cfDNA levels or cfDNA changes during HD. The increase in plasma cfDNA during HD did not correlate with dialysis duration, its efficacy, or ultrafiltration. An association between magnitude of diuresis and cfDNA levels in HD-S was found (r = 0.58; p < 0.05).

Conclusions: The behavior of cfDNA during HD after long and short interdialytic interval is inconsistent and cannot be explained by changes in laboratory and clinical parameters. The observed relationship of plasma cfDNA levels with diuresis deserves further investigation.