β2-Microglobulin Elimination in End-Stage Renal Disease Patients on Renal Replacement Therapy
β2-microglobulin (β2M) is a small molecular mass protein associated with dialysis amyloidosis. We have studied β2M elimination in end-stage renal disease (EsRD) patients treated by peritoneal dialysis. In 12 patients on continuous ambulatory peritoneal dialysis (CAPD) and 7 patients on intermittent peritoneal dialysis (IPD) 30.4±4.2 mg/day and 21.3± 1.8 mg/12 hour of β2M, respectively, were removed by dialysis fluid. Approximately the same amount of β2M was removed by each of four 2-L exchanges in CAPD; however, the most efficient removal of β2M was in the first IPD exchange. Serum β2M levels in these patients were 25.7 ±4.4 and 31.4±5.2 mg/L, respectively. In 24 patients on hemodialysis using cuprophan membrane the serum level of β2M was 55.1±4.1 mg/L. After a 3-month dialysis on polyacrylonitrile (PAN) membrane, the serum β2M level decreased to 45.0±2.3 mg/L. A substantial amount of β2M was removed by urine, 14.6.:1:2.3 mg/L, and saliva, 2.3±0.4 mg/L. This study has shown markedly increased β2M levels in patients on conventional hemodialysis treatment, predisposing to β2M-related amyloidosis. A significant amount of β2M was removed during both CAPD and IPD treatment.