THE EFFECT OF MEMBRANE-CHARACTERISTICS ON TUMOR-NECROSIS-FACTOR KINETICS DURING HEMODIALYSIS

We measured serum β2-M and TNFα before and after a 4-h haemodialysis performed on two membranes with different characteristics, either cuprophane (n = 40) or polyacrylonitrile (AN69) (n = 31). Kinetic studies including determinations at 0, 15, 30, 60 and 240 min were also performed during haemodialysis sessions on cuprophane (n = 14) and AN69 (n = 12). After a 240-min haemodialysis, TNFα increased on cuprophane (21.95 ± 3.46 to 37.20 ± 4.60 pg/ml, P< 0.001) but remained stable on AN69 (16.70 ±2.60 to 19.90±2.90 pg/ml, NS). Kinetic studies revealed that on cuprophane, β2-M increased progressively from 40.72 ± 4.41 to 45.71 ±4.77 mg/l (P<0.001) at 240 min with a significant increase already noted at 60 min. TNFI remained stable during the first 60 min but increased significantly at 240 min (34.14 ± 6.60 to 49.71 ± 8.78 pg/ml, P<0.001). The percentage increment in TNFI (50.5%) was significantly greater at 240 min than the percentage increment in β2M (13.4%), a finding suggestive of net generation of TNFI. On AN69, β2-M decreased progressively from 31.82 ± 2.70 to 27.30±2.26mg/l (P<0.001). TNFI a decreased transiently at 15 min but returned subsequently to control values (0 and 240 min: 25.00 ± 3.81 and 29.75 ± 3.59 pg/ml respectively, NS). Our data suggest a net release of TNFα during cuprophane but not during polyacrylonitrile haemodialysis. This release might play a role in the stimulation of β2-M production and thus in the genesis of dialysis amyloidosis. © 1990 European Dialysis and Transplant Association-European Renal Association.