Ｓｅｖｅｒｅ　ｓｅｐｓｉｓにおいて持続的血液ろ過透析（ＣＨＤＦ）が補体系に及ぼす影響

The aim of this study is to evaluate the changes in the complement cascade during continuous hemodiafiltration (CHDF) and to determine the effect of CHDF on severe sepsis. The subjects were 9 patients who had undergone CHDF for at least 3 days in our ICU. We assessed the complement function and concentrations or activities of CH50, C1q, C3a, C3 proactivator, C3, C4 and also albumin, colloid osmotic pressure (COP) and C-reactive protein (CRP). Blood samples were obtained from an arterial catheter before and 3 days after the start of CHDF. Blood sampled from both membranesited and CHDF filtrate was obtained at 2, 6, and 12 hours after the start of CHDF. Data were expressed as mean±SD. Statistical analysis was performed on the changes during CHDF between the groups and at sites both upstream and downstream of the hemofilter membrane. Five patients survived (S-group) and 4 patients did not survived (N-group). Levels of C3a were extremely high and levels of CH50 and C3 were low in the patients with severe sepsis. Levels of C3a before CHDF were extremely high and decreased significantly during CHDF in the S-group. Levels of CH50 and C3 before CHDF were low, but did not change significantly during CHDF. The levels of C1q, C4 and C3 proactivator were within their normal range and did not change during CHDF. CH50 and C3a were detected in the CHDF filtrate. The levels of C3a increased significantly on the downstream site compared with the upstream site of the hemofilter membrane. Albumin and COP increased significantly and CRP decreased significantly 3 days after the start of CHDF in the survival group. It was thought that an alternative pathway of complement cascade was activated in the patients with severe sepsis. CHDF can be an effective therapy for severe sepsis because C3a (chemotactic factor) decreased significantly during CHDF and this decrease in C3a might contribute to the improvement of the outcome. The hemofilter membrane of CHDF may, however, have the potential to activate the complement cascade.