Epidemiology and Management of Acquired Angioedema Due to C1 Inhibitor Deficiency

AAE-C1-INH (acquired angioedema owing to C1-inhibitor (C1-INH) deficiency) is a dangerous illness that can lead to asphyxiation due to laryngeal edoema. Only around 1% to 2% of angioedema cases are classified as HAE or AAE, with HAE being 10 times more prevalent than AAE. The sole clinical distinction between HAE and AAE is the age at which symptoms appea, AAE-C1-INH is usually diagnosed after 40 years of age. There is no licensed therapy for AAE-C1-INH at this time. AAE-C1-INH attacks are treated with HAE-C1-INH medicines such plasma-derived C1-INH concentrate (pdC1-INH) and the bradykinin B2 receptor antagonist, icatibant. These on-demand medications are thought to be most helpful when provided early in the attack. However, there is a scarcity of published data on the efficacy and safety of AAE-C1-INH therapies.

Malignancy and immune disorders in patients with hereditary angioedema

Background Hereditary angioedema (HAE) is an inherited condition manifesting as recurrent angioedema episodes which is caused by deficiency or dysfunction of C1 inhibitor. Although complement dysregulation has historically been shown to be associated with various malignancy and immune disorders, it is currently not known if HAE patients are at an increased risk of developing malignancy or autoimmune conditions. Case presentation We reviewed the charts of 49 HAE patients and identified 6 patients who had a co-existing malignancy diagnosis (two with breast cancer, one with melanoma, one with pancreatic cancer, one with renal cancer and one with cervical dysplasia) and 6 patients who had a diagnosis of a co-existing immune disorder (two with rheumatoid arthritis, two with ulcerative colitis, one with chronic urticaria with hypothyroidism and one with Sjogren’s syndrome). Nearly all malignancy cases occurred in older HAE patients (> 50 years) and malignancy was diagnosed before HAE in 3 of the patients. Conclusions Our case series identified multiple hereditary angioedema (HAE) patients with co-existing malignancy and immune disorders. Based on these findings, we would advocate that physicians managing HAE patients should maintain a high index of suspicion for these conditions and that in patients with angioedema, C1 inhibitor deficiency and malignancy, a diagnosis of HAE should still be considered in addition to acquired angioedema (AAE).

Physicochemical and Biological Characterization of rhC1INH Expressed in CHO Cells

The disfunction or deficiency of the C1 esterase inhibitor (C1INH) is associated with hereditary or acquired angioedema (HAE/AAE), a rare life-threatening condition characterized by swelling in the skin, respiratory and gastrointestinal tracts. The current treatment options may carry the risks of either viral infection (plasma-derived Berinert®) or immune reaction (human recombinant C1INH from rabbit milk, Ruconest®). This study describes the physicochemical and biological characterization of a novel recombinant human C1 esterase inhibitor (rhC1INH) from Chinese hamster ovary (CHO) cells for the treatment of hereditary angioedema compared to the marketed products Berinert® and Ruconest®. The mass spectrometry results of total deglycosylated rhC1INH revealed a protein with a molecular mass of 52,846 Da. Almost full sequence coverage (98.6%) by nanoLC-MS/MS peptide mapping was achieved. The purity and C1s inhibitory activity of rhC1INH from CHO cells are comparable with Ruconest®, although we found differences in charge isoforms distribution, intact mass values, and N-glycans profile. Comparison of the specific activity (IC50 value) of the rhC1INH with human C1 esterase inhibitor from blood serum showed similar inhibitory properties. These data allow us to conclude that the novel rhC1INH molecule could become a potential therapeutic option for patients with HAE/AAE.

Larynx Angioedema as a Signal in Chronic Lymphocytic Leukemia: A Case-based Guide for Acquired Angioedema in the Setting of Lymphoproliferative Disorders

ABSTRACT Patients with angioedema can present to the internal medicine, emergency medicine, dermatology, or ear nose throat clinics. Physicians may need to assess the patients whose angioedema is unresponsive to antihistamines systematically in collaboration with other subspecialties including hematology, rheumatology, allergy, and immunology. We aimed to provide a concise review of the diagnosis and multi-disciplinary management of acquired angioedema through a case presentation. A 61-year-old woman presented with recurrent angioedema of 4 episodes within one year. She was evaluated by various disciplines such as dermatology and emergency medicine. Antihistamines and steroids were not effective. The complete blood count (CBC) results indicated lymphocytosis (lymphocyte count=9100 k/μL) and further evaluation of the lymphocytosis with flow cytometry immunophenotyping confirmed a diagnosis of chronic lymphocytic leukemia. Since the acquired angioedema diagnosis was confirmed with low C4, C1q, and C1 esterase inhibitor levels, Rituximab 375 mg/m2 was administered once a week for 4 weeks. The frequency of attacks decreased after rituximab therapy and none of them were life-threatening. In conclusion, when the effective treatment is initiated for the primary diagnosis in acquired angioedema, the numerous emergency department visits, hospitalizations, and the mortality due to life-threatening angioedema episodes can be avoided. Keywords: Angioedema, larynx angioedema, emergency, chronic lymphocytic leukemia, life-threatening angioedema