A Pilot Study to Evaluate the Use of C1 Esterase Inhibitor (Human) in Patients With Acute Antibody-Mediated Rejection

Inclusion Criteria include: * ≥18 years of age. * Weigh ≥50 kg. * Donor specific antibody identified. Exclusion Criteria include: * Any surgical or medical condition that could interfere with the administration of study drug or interpretation of study results. * History of allergic reaction to C1 Esterase Inhibitor or other blood products. * Participation in the active dosing phase of any other investigational drug study within 30 days prior to dosing with study drug. * Pregnancy or lactation. * Receipt of any experimental agents for AMR within 1 month prior to the first dose of study drug. * Any infection that causes hemodynamic compromise. * History of bleeding or clotting abnormality.