Portal de Periódicos da CAPES

Increased susceptibility to erythrocyte C5b-9 deposition and complement-mediated lysis in chronic renal failure

1999; Elsevier BV; Volume: 55; Issue: 2 Linguagem: Inglês

10.1046/j.1523-1755.1999.00277.x

1523-1755

Jonathan Himmelfarb, Ellen McMonagle, Diane Holbrook, Raymond M. Hakim,

Neonatal Health and Biochemistry

Increased susceptibility to erythrocyte C5b-9 deposition and complement-mediated lysis in chronic renal failure.BackgroundDecreased red blood cell survival contributes to the anemia of chronic renal failure patients. Because patients on chronic dialysis therapy are frequently exposed to excessive complement activation, we investigated the susceptibility of this patient population to erythrocyte C5b-9 deposition, complement-mediated lysis, and ghost formation.MethodsWe developed a flow cytometric assay using antibodies to both glycophorin and the C5b-9 complex to detect C5b-9 deposition on intact erythrocytes and erythrocyte ghosts. Serum C5b-9 levels and C5b-9 deposition on erythrocyte ghosts were measured by enzyme-linked immunosorbent assay.ResultsA significant increase in C5b-9 deposition on intact erythrocytes was demonstrated in patients with advanced chronic renal failure (2.2±0.5%) and in patients on chronic maintenance hemodialysis (2.3±0.4%) compared with normal volunteers (0.9±0.1%, P = 0.005 vs. chronic renal failure, P < 0.001 vs. chronic hemodialysis patients). There was also a significantly higher percentage of C5b-9–positive erythrocyte ghosts in patients with advanced chronic renal failure (20.6±5%) and in chronic hemodialysis patients (15.5±3.1%) compared with normal controls (2.6±0.9%, P ≤ 0.001 vs. advanced chronic renal failure and chronic hemodialysis patients). Treatment of erythrocyte preparations with cobra venom factor, which activates the complement cascade, resulted in dramatic increases in the percentages of C5b-9–positive erythrocyte ghosts in patients with chronic renal failure (49.9±6.9%) and in chronic hemodialysis patients (45.0±4.2%) compared with normal volunteers (22.3±2.7%, P < 0.001 vs. chronic renal failure and chronic hemodialysis patients). Erythrocyte membrane expression of the complement regulatory proteins CD59 and CD55 did not significantly differ between normal controls and hemodialysis patients. Plasma C5b-9 levels after cobra venom factor stimulation were higher in chronic renal failure patients (538 μg/ml) compared with normal controls (345 μg/ml, P < 0.001).ConclusionsPatients with chronic renal failure and on hemodialysis therapy are susceptible to erythrocyte C5b-9 deposition with subsequent lysis and ghost formation. Susceptibility to complement-mediated erythrocyte injury may contribute to the anemia of chronic renal disease. Increased susceptibility to erythrocyte C5b-9 deposition and complement-mediated lysis in chronic renal failure. Decreased red blood cell survival contributes to the anemia of chronic renal failure patients. Because patients on chronic dialysis therapy are frequently exposed to excessive complement activation, we investigated the susceptibility of this patient population to erythrocyte C5b-9 deposition, complement-mediated lysis, and ghost formation. We developed a flow cytometric assay using antibodies to both glycophorin and the C5b-9 complex to detect C5b-9 deposition on intact erythrocytes and erythrocyte ghosts. Serum C5b-9 levels and C5b-9 deposition on erythrocyte ghosts were measured by enzyme-linked immunosorbent assay. A significant increase in C5b-9 deposition on intact erythrocytes was demonstrated in patients with advanced chronic renal failure (2.2±0.5%) and in patients on chronic maintenance hemodialysis (2.3±0.4%) compared with normal volunteers (0.9±0.1%, P = 0.005 vs. chronic renal failure, P < 0.001 vs. chronic hemodialysis patients). There was also a significantly higher percentage of C5b-9–positive erythrocyte ghosts in patients with advanced chronic renal failure (20.6±5%) and in chronic hemodialysis patients (15.5±3.1%) compared with normal controls (2.6±0.9%, P ≤ 0.001 vs. advanced chronic renal failure and chronic hemodialysis patients). Treatment of erythrocyte preparations with cobra venom factor, which activates the complement cascade, resulted in dramatic increases in the percentages of C5b-9–positive erythrocyte ghosts in patients with chronic renal failure (49.9±6.9%) and in chronic hemodialysis patients (45.0±4.2%) compared with normal volunteers (22.3±2.7%, P < 0.001 vs. chronic renal failure and chronic hemodialysis patients). Erythrocyte membrane expression of the complement regulatory proteins CD59 and CD55 did not significantly differ between normal controls and hemodialysis patients. Plasma C5b-9 levels after cobra venom factor stimulation were higher in chronic renal failure patients (538 μg/ml) compared with normal controls (345 μg/ml, P < 0.001). Patients with chronic renal failure and on hemodialysis therapy are susceptible to erythrocyte C5b-9 deposition with subsequent lysis and ghost formation. Susceptibility to complement-mediated erythrocyte injury may contribute to the anemia of chronic renal disease.