Similar to interferon production in pristane-treated mice [8 ], ischemia-perfusion injury in mice is mediated by the early classical complement cascade and natural IgM [9 (link)]. Human natural IgM is as effective at inducing ischemia/reperfusion injury as murine IgM [10 (link)]. In light of these observations and in view of the relative ease of obtaining human vs. mouse IgM, the requirement for immunoglobulin in DAH was evaluated by administering purified human IgM (50 or 200 μg/mouse, Sigma-Aldrich), murine IgG (200 μg/mouse, Sigma-Aldrich), or PBS i.v. to μMT mice 1-d before and 7-d after pristane treatment. DAH was assessed at 14-d.