A Study to Evaluate the Benefit of RUCONEST® in Subjects Who Experience ADRs Related to IVIG Infusions

Inclusion Criteria: * Age 18 years and older experiencing ADRs related to IVIG infusions * Stable dose of IVIG for 3 months * Willing to comply with all aspects of the protocol, including blood draws * Female patients of childbearing potential who are sexually active must be willing to use an acceptable form of contraception. Acceptable forms of contraception are defined as those with a failure rate \< 1% when properly applied and include: a combination oral pill, some intra-uterine devices, and a sterilized partner in a stable relationship. Female patients must not be pregnant, planning to become pregnant, or be actively breastfeeding through the entire study period. Exclusion Criteria: * Receiving treatment for HAE, either prophylactic or acute therapy * Patients with medical history of allergy to rabbits or rabbit-derived products (including rhC1INH) * Patients who are pregnant, or breastfeeding, or are currently intending to become pregnant. * Patients who, in the investigator's opinion, might not be suitable for the trial