CYTOKINE PRODUCTION DURING IN-VITRO HEMODIALYSIS WITH NEW AND FORMALDEHYDE-REPROCESSED OR RENALIN-REPROCESSED CELLULOSE DIALYZERS

Critics of reuse have suggested that patients treated with reprocessed dialyzers are exposed to pyrogen trapped from the water or solutions used during the reprocessing cycle, thereby triggering the synthesis a nd release of proinflammatory cytokines, resulting in cachexia. To tes t this hypothesis, the production of interleukin (IL)-1 alpha by perip heral blood mononuclear cells (PBMC) during in vitro dialysis with new or reprocessed cellulose dialyzers was compared. An in vitro closed-l oop dialysis circuit was created with standard hemodialysis blood line s and either new cellulose dialyzers or dialyzers reprocessed 10 times with either formaldehyde/bleach (formaldehyde) or peracetic acid/hydr ogen peroxide mixture (Renalin). The circuit was rinsed with 2 L or mo re of pyrogen-free normal saline before the start of in vitro dialysis until the blood compartment tested negative for residual formaldehyde /Renalin. Heparinized whole blood from healthy volunteers was circulat ed for 3 h in the blood compartment at 100 mL/min at 37 degrees C. The dialysate compartment was sealed. Peripheral blood mononuclear cells (PBMC) were harvested from the blood compartment before and at the end of 3 h of in vitro dialysis. Total IL-1 alpha synthesis (cell associa ted plus secreted) by unstimulated and endotoxin-stimulated PBMC was m easured by a specific, non-cross-reactive radioimmunoassay. After 3 h of in vitro dialysis, IL-1 alpha production (in picograms per 2.5 mill ion PBMC) by unstimulated PBMC increased from 354 +/- 63 at baseline t o 454 +/- 57 with new dialyzers (P = 0.25), from 453 +/- 101 to 450 +/ - 67 with formaldehyde-reprocessed dialyzers (P = 0.98), and from 360 +/- 61 to 538 +/- 144 with Renalin-reprocessed dialyzers (P = 0.23). I L-1 alpha production by endotoxin-stimulated PBMC increased from 5,214 +/- 996 to 9,237 +/- 929 with new dialyzers (P < 0.001), from 6,395 /- 955 to 9,636 +/- 1,058 with formaldehyde-reprocessed dialyzers (P = 0.006), and from 7,561 +/- 1,000 to 10,092 +/- 2,470 with Renalin-rep rocessed dialyzers (P = 0.32). However, there were no significant diff erences among groups with respect to IL-1 alpha production by unstimul ated or endotoxin-stimulated PBMC either before or after 3 h of in vit ro dialysis. These data argue against the suggestion that exposure to reprocessed dialyzers results in enhanced synthesis of proinflammatory cytokines. In fact, reprocessed dialyzers probably induce less cytoki ne production than do new cellulose dialyzers.