Dialysis leukopenia and hypoxemia in a patient without measurable complement activity

Summary We have studied complement activity, total leukocyte counts,\(P_{O_2 } \) and acid-base balance during a single hemodialysis with cuprophan membranes in a patient with hereditary angioedema and C3NeF-positive chronic membranoproliferative glomerulonephritis. Before, during and after the dialytic procedure plasma complement activity (total hemolytic complement, classical and alternative pathway activities) was not detectable and no C3-conversion occurred, while profound leukopenia (from 8,500 to 1,800 leukocytes/µl) and hypoxemia (from 101.8 to 86 mmHg\(P_{O_2 } \)) were found within 20 min from the initiation of hemodialysis. Similar results were obtained by studying the same parameters during two additional hemodialytic procedures.In vitro experiments showed that the patient’s C3 could not be converted, either by cuprophan or zymosan, a specific and potent complement activator, even under optimal experimental conditions. Our data demonstrate that complement activation is not the only possible mechanism responsible for early leukopenia (as well as hypoxemia) during dialysis with cuprophan membranes.