Acute changes in C3a and C5a in an anaphylactoid reaction in hemodialysis patients

Blood sample were collected from both the arterial and venous lines of the patients undergoing hemodialysis using cuprophan membrane at several time intervals. Radioimmunoassay was then applied to measure the C3a and C5a levels. C3a levels from the arterial lines of patients undergoing uneventful hemodialysis were 463.2 +/- 51.3 ng/ml (mean +/- S.D.), 1112.9 +/- 109.9, 956.0 +/- 72.1, and 721.2 +/- 49.6 at 0, 15, 120 and 360 min, respectively. C5a levels did not change significantly during uneventful hemodialysis. C3a and C5a levels were significantly higher in the blood from the venous lines than those from the arterial lines, a finding indicating that complement activation via alternative pathway takes place in the dialyzer. C3a and C5a levels were markedly elevated in patients with anaphylactoid reaction. Reuses of dialyzers on the patients having a history of an anaphylactoid reaction during hemodialysis suppressed not only the rise of C3a levels, but also the recurrence of the reaction. From these findings, it is concluded that rises of C3a and C5a in the arterial lines of patients are causally related to the induction of anaphylactoid reaction during hemodialysis.