Hereditary and acquired angioedema

Physician- and patient-reported outcomes by hereditary angioedema type: Data from a real-world study

Background: Hereditary angioedema (HAE) is a rare genetic condition characterized by painful and often debilitating swelling attacks. Little is known about the differences in outcomes between patients with HAE types I or II (type I: HAE caused by C1 esterase inhibitor deficiency; type II: HAE caused by C1 esterase inhibitor dysfunction), with decreased or dysfunctional C1 esterase inhibitor (C1-INH), and those with normal C1-INH (nC1-INH-HAE). Objective: To compare physician- and patient-reported real-world outcomes in patients with HAE types I/II versus patients with nC1-INH-HAE. Methods: Data were drawn from the Adelphi HAE Disease Specific ProgrammeTM a real-world, cross-sectional survey of HAE-treating physicians and their patients in the United States conducted between July and November 2021. Physicians reported patient disease activity and severity, and recent attack history. Patient-reported outcomes were collected. Bivariate tests used were either the Student's t-test, the Fisher exact test, or Mann-Whitney U test. Results: Physicians (N = 67) provided data on 368 patients (92.4% HAE types I/II and 7.6% nC1-INH-HAE). Physicians reported that a higher proportion of patients with nC1-INH-HAE had moderate or high disease activity and moderate or severe disease severity both at diagnosis and at data collection versus those with HAE types I/II. Patients with nC1-INH-HAE versus patients with HAE types I/II experienced increased attack severity (34.6% versus 4.4%) and hospitalization rate during the most recent attack (39.3% versus 6.6%), and reported lower health status and quality of life, via the European Quality of Life 5 Dimension 5 Level (US tariff) and Angioedema Quality of Life, respectively. On average, 25% of the patients with nC1-INH-HAE reported absenteeism and work or activity impairment due to HAE compared with 2.7% of patients with HAE types I/II. Both patient groups reported improvements in disease activity and severity from diagnosis to the time of data collection. Conclusion: These real-world findings suggest that patients with nC1-INH-HAE have increased disease activity and severity, and experience greater impairment to their quality of life, work, and daily functioning than patients with HAE types I/II. Powered statistical analyses are required to confirm these findings.

Exploring disease-specific metabolite signatures in hereditary angioedema patients

Introduction

Hereditary angioedema (HAE) is a rare, life-threatening autosomal dominant genetic disorder caused by a deficient and/or dysfunctional C1 esterase inhibitor (C1-INH) (type 1 and type 2) leading to recurrent episodes of edema. This study aims to explore HAE patients' metabolomic profiles and identify novel potential diagnostic biomarkers for HAE. The study also examined distinguishing HAE from idiopathic angioedema (AE).

Methods

Blood plasma samples from 10 HAE (types 1/2) patients, 15 patients with idiopathic AE, and 20 healthy controls were collected in Latvia and analyzed using LC-MS based targeted metabolomics workflow. T-test and fold change calculation were used to identify metabolites with significant differences between diseases and control groups. ROC analysis was performed to evaluate metabolite based classification model.

Results

A total of 33 metabolites were detected and quantified. The results showed that isovalerylcarnitine, cystine, and hydroxyproline were the most significantly altered metabolites between the disease and control groups. Aspartic acid was identified as a significant metabolite that could differentiate between HAE and idiopathic AE. The mathematical combination of metabolites (hydroxyproline * cystine)/(creatinine * isovalerylcarnitine) was identified as the diagnosis signature for HAE. Furthermore, glycine/asparagine ratio could differentiate between HAE and idiopathic AE.

Conclusion

Our study identified isovalerylcarnitine, cystine, and hydroxyproline as potential biomarkers for HAE diagnosis. Identifying new biomarkers may offer enhanced prospects for accurate, timely, and economical diagnosis of HAE, as well as tailored treatment selection for optimal patient care.

Inter-α-trypsin inhibitor heavy chain 4 (ITIH4) as a compensatory protease inhibitor in hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is a genetic disorder that manifests as recurrent angioedema attacks, most frequently due to absent or reduced C1 inhibitor (C1INH) activity. C1INH is a crucial regulator of enzymatic cascades in the complement, fibrinolytic, and contact systems. Inter-α-trypsin inhibitor heavy chain 4 (ITIH4) is an abundant plasma protease inhibitor that can inhibit enzymes in the proteolytic pathways associated with HAE. Nothing is known about its role in HAE.

OBJECTIVE

We investigated ITIH4 activation in HAE, establishing it as a potential biomarker, and explored its involvement in HAE-associated proteolytic pathways.

METHODS

Specific immunoassays for noncleaved ITIH4 (intact ITIH4) and an assay detecting both intact and cleaved ITIH4 (total ITIH4) were developed. We initially tested serum samples from HAE patients (n = 20), angiotensin-converting enzyme inhibitor-induced edema patients (ACEI) (n = 20), and patients with HAE of unknown cause (HAE-UNK) (n = 20). Validation involved an extended cohort of 80 HAE patients (60 with HAE-C1INH type 1, 20 with HAE-C1INH type 2), including samples taken during attack and quiescent disease periods, as well as samples from 100 healthy controls.

RESULTS

In 63% of HAE patients, intact ITIH4 assay showed lower signals than total ITIH4 assay. This difference was not observed in ACEI and HAE-UNK patients. Western blot analysis confirmed cleaved ITIH4 with low intact ITIH4 samples. In serum samples lacking intact endogenous ITIH4, we observed immediate cleavage of added recombinant ITIH4, suggesting continuous enzymatic activity in the serum. Confirmatory HAE cohort analysis revealed significantly lower intact ITIH4 levels in both type 1 and type 2 HAE patients compared to controls, with consistently low intact/total ITIH4 ratios during clinical HAE attacks.

CONCLUSION

The disease-specific low intact ITIH4 levels highlight its unique nature in HAE. ITIH4 may exhibit compensatory mechanisms in HAE, suggesting its utility as a diagnostic and prognostic biomarker. The variations during quiescent and active disease periods raise intriguing questions about the dynamics of proteolytic pathways in HAE.

Anesthetic management with remimazolam for a patient with hereditary angioedema:a case report

BACKGROUND

Hereditary angioedema (HAE), a genetic disorder caused by C1-inhibitor deficiency or dysfunction, may cause mucosal edema in the upper airway during tracheal intubation and extubation.

CASE REPORT

A 57-year-old man with HAE and a history of laryngeal edema, scheduled to undergo cervical laminoplasty under general anesthesia. General anesthesia was induced by continuous injection of remimazolam and remifentanil, during which manual mask ventilation and intubation were performed without difficulty. The patient was extubated under deep anesthesia. After emergence from general anesthesia, he had no significant upper airway edema and was treated with a C1-inhibitor seven hours post-surgery because of slight tongue swelling. No additional airway edema was observed, and the patient was discharged from the intensive care unit the following day.

CONCLUSIONS

Deep anesthesia tracheal extubation with remimazolam may be effective in preventing upper airway edema during anesthetic management in patients with HAE. J. Med. Invest. 71 : 184-186, February, 2024.

Universal Access to On-Demand Treatment of Patients with Hereditary Angioedema, the Chilean Experience

Background: In Chile, patients with hereditary angioedema (HAE) type I and type II are protected under Ley Ricarte Soto (LRS), which guarantees access to on demand plasma-derived C1-INH (pdC1-INH) since 2018. We aimed to analyze the first 3 years of LRS. Methods: Review of the LRS database between 2018 and 2021. Results: During the study period, 154 patients were covered by LRS, with an estimated prevalence of HAE in Chile at 0.8:100,000 inhabitants. A delay in diagnosis of 22 years was noted, 50 patients received epinephrine during an attack before the diagnosis of HAE. Mean number of attacks per year was 8, with 50% of adults and 42% of children experiencing more than 1 attack per month. Conclusion: Disease awareness must improve to reduce the diagnostic delay of HAE. Long-term prophylactic medications should be included in LRS to treat patients with high attack rates and control the costs of frequent on-demand treatment with pdC1-INH.

Hypersensitivity reactions amongst Hungarian Patients with Hereditary Angioedema due to C1-Inhibitor Deficiency

Background

In hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE), bradykinin-mediated submucosal and/or subcutaneous angioedema dominates the clinical picture. The deficiency of C1-inhibitor can lead to the over-activation of the complement system. Complement plays an important role in all types of hypersensitivity reactions. On the other hand, during the degranulation of mast cells, heparin is also released amongst other substances. Heparin can activate the plasma kinin-kallikrein system, leading to bradykinin generation. These observations suggest a possible connection between C1-INH-HAE and mast cell-mediated hypersensitivity reactions.

Objective

To assess the occurrence of hypersensitivity reactions in the Hungarian C1-INH-HAE population.

Methods

Patients filled out a questionnaire of 112 questions, either online or on paper. The questions were about hypersensitivity and C1-INH-HAE symptoms, the relation between these 2, general health, and demographic data. The study protocol was approved by the institutional review board of Semmelweis University, Budapest, and informed consent was obtained from the participants.

Results

One hundred and six patients (64 female, 42 male, median age 46 years) responded, with 63.2% having hypersensitivity. Hypersensitivity was provoked by pollen in 25.5% of patients, by contact sensitivity in 22.6%, by food in 21.7%, by insect sting in 19.8%, by pet in 15.1%, by drug in 14.2%, by dust mite in 5.7%, and by mold in 1.9%. In 11 patients, hypersensitivity symptoms appeared after the diagnosis of C1-INH-HAE. Six hypersensitive patients experienced improvement in their symptoms; 42 remained the same, but none experienced worsening after the diagnosis of C1-INH-HAE. In 7.8% of the hypersensitive patients, a C1-INH-HAE attack worsened the hypersensitivity symptoms, while 15.7% of the hypersensitive patients experienced a C1-INH-HAE attack provoked by contact with the provoking factor.

Conclusion

While 63.2% of our C1-INH-HAE patients have reported hypersensitivity symptoms, Eurostat's latest data puts the prevalence of self-reported allergies in Hungary at 19.3%. Since in our experience most Hungarian patients report hypersensitivity reactions as allergies, this may support a possible connection between the 2 diseases, but further molecular studies are needed.

Pseudo-Allergies in the Emergency Department: A Common Misdiagnosis of Hypersensitivity Type 1 Allergic Reaction

Type-1 hypersensitivity reaction represents an acute IgE-mediated reaction that can cause life-threatening conditions, such as anaphylactic shock, angioedema, and airway obstruction. Other reactions that can mimic type-1 hypersensitivity reactions include IgE-independent mast cell degranulation, bradykinin-mediated reactions, leukotrienes-mediated reactions, and pseudo-allergies. We use the term pseudo-allergy in this article for histamine-mediated reactions that are mast cell-independent. We did not discuss pseudo-allergic reactions that are not acute or life-threatening, such as celiac disease, Heiner's syndrome, eosinophilic esophagitis, and food protein-induced enterocolitis in our article because the emergency department is not the primary location to diagnose or treat these reactions. Herein, we present some allergic-like reactions that can be life-threatening, such as scombroid food poisoning (SFP), bradykinin-induced angioedema, IgE-independent angioedema, opioid-induced angioedema, and non-steroidal anti-inflammatory drug (NSAID)-induced hypersensitivity and angioedema. These reactions may have different treatments based on their mechanism of reaction. Histamine-mediated reactions, such as SFP, histamine-mediated angioedema, and mast cell degranulation induced by NSAIDs, and opioids can be treated with antihistamines, epinephrine, and corticosteroids. Bradykinin-induced angioedema, including hereditary angioedema and acquired angioedema, can be treated with fresh frozen plasma. Hereditary angioedema can be treated with many FDA-approved targeted medications, such as plasma-derived C1-INH, plasma kallikrein inhibitor (Ecallantide), and selective bradykinin-2 receptor antagonist (Icatibant). However, these targeted agents are not well-studied enough to be used for acquired angioedema. It is crucial for emergency medicine physicians to be familiar with and predict these reactions to prevent misdiagnosis, be prepared to treat these life-threatening conditions appropriately without delay and eliminate patients' exposure to any unnecessary investigations or treatments.

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

C1-inhibitor treatment in patients with severe complement-mediated autoimmune hemolytic anemia

Complement-mediated (CM) autoimmune hemolytic anemia (AIHA) is characterized by the destruction of red blood cells (RBCs) by autoantibodies that activate the classical complement pathway. These antibodies also reduce transfusion efficacy via the lysis of donor RBCs. Because C1-inhibitor (C1-INH) is an endogenous regulator of the classical complement pathway, we hypothesized that peritransfusional C1-INH in patients with severe CM-AIHA reduces complement activation and hemolysis, and thus enhances RBC transfusion efficacy. We conducted a prospective, single-center, phase 2, open-label trial (EudraCT2012-003710-13). Patients with confirmed CM-AIHA and indication for the transfusion of 2 RBC units were eligible for inclusion. Four IV C1-INH doses (6000, 3000, 2000, and 1000 U) were administered with 12-hour intervals around RBC transfusion. Serial blood samples were analyzed for hemolytic activity, RBC opsonization, complement activation, and inflammation markers. Ten patients were included in the study. C1-INH administration increased plasma C1-INH antigen and activity, peaking at 48 hours after the first dose and accompanied by a significant reduction of RBC C3d deposition. Hemoglobin levels increased briefly after transfusion but returned to baseline within 48 hours. Overall, markers of hemolysis, inflammation, and complement activation remained unchanged. Five grade 3 and 1 grade 4 adverse event occurred but were considered unrelated to the study medication. In conclusion, peritransfusional C1-INH temporarily reduced complement activation. However, C1-INH failed to halt hemolytic activity in severe transfusion-dependent-CM-AIHA. We cannot exclude that posttransfusional hemolytic activity would have been even higher without C1-INH. The potential of complement inhibition on transfusion efficacy in severe CM-AIHA remains to be determined.

A Rare Presentation of Hydralazine-Induced Lupus in the Setting of Pericarditis With Concomitant Angioedema

Drug-induced lupus (DIL) usually presents after starting a medication known to induce DIL. However unusual presentations are rare, as such, our patient presented with initial signs and symptoms of pericarditis. Once treated as such, he progressively declined to symptoms of angioedema and worsening cardiopulmonary status. On first admission, the patient presented with chest pain that was worsened by laying down and improved by sitting up. CT Angiography (CTA) showed mild pericardial effusion, and EKG showed diffuse ST elevation, both suggestive of pericarditis, for which the patient was discharged on colchicine. The patient was readmitted one day later with swelling of the neck and tongue. The patient was re-evaluated, tested for autoantibodies, and found a positive antinuclear antibody (ANA) suggesting a diagnosis of lupus, most likely due to hydralazine. We report a rare presentation of drug-induced lupus initially presenting with pericarditis which evolved into worsening angioedema which has not been reported in the literature thus far. Pericarditis and angioedema may be the initial presentation for a patient with drug-induced lupus. Antinuclear and anti-histone antibodies are highly sensitive and specific respectfully for drug-induced lupus. Early diagnosis and time-appropriate discontinuation of the offending agent for patients can be life-saving.

National survey on clinical and genetic characteristics of patients with hereditary angioedema in Latvia

BACKGROUND

Hereditary angioedema (HAE) is a rare and life-threatening inborn error of immunity. HAE is mostly caused by pathogenic variations in the serine protease inhibitor gene 1 (SERPING1), leading to deficient or dysfunctional C1-inhibitor (C1-INH), overproduction of bradykinin, and development of recurrent subcutaneous and/or submucosal oedema. The prevalence of HAE is 1 in 50,000 - 100000 people worldwide. We aimed to describe the clinical features and genetic spectrum of hereditary angioedema with C1-INH deficiency (C1-INH-HAE) in Latvia.

METHODS

All patients from Latvia diagnosed with HAE (types I/II) from 2006 to March 2022 were included in the study. Laboratory tests and clinical data were analysed, and genetic tests with Sanger sequencing and whole genome sequencing were performed.

RESULTS

The study identified 10 C1-INH-HAE patients (nine females, one male) from eight families. The point prevalence of HAE in Latvia is 0.53 per 100 000 inhabitants. Of all patients, seven (70%) had HAE type I and three (30%) had HAE type II. The median age of patients was 54 years and the median age at onset of symptoms was 15 years. A significant delay (median 20.5 years) until diagnosis was observed, and 60% of patients had a positive family history of angioedema. All HAE patients have been hospitalised a median two times during their lifetime. Skin (100%), abdominal (80%), and airway (80%) oedema were the most frequent symptoms. Triggering factors (60%) and prodromal symptoms (90%) were referred. Attacks were severe in 50% of patients, moderate in 10%, and mild in 40%. Pathogenic variations of SERPING1 were identified in eight patients (six families), confirming the diagnosis molecularly. In two patients (two families), no pathogenic variations in the genes were found even after whole genome sequencing.

CONCLUSIONS

Current data shows a significant delay and clear underdiagnosis of HAE in Latvia. Higher awareness and better information and communication between doctors would improve the diagnosis and management of HAE; as would screening of family members, patients with recurrent angioedema unresponsive to antihistamines and glucocorticoids, and patients with recurrent episodes of severe, unexplained abdominal pain.

Acquired Angioedema in Selected Neoplastic Diseases

Background and Objectives. Acquired angioedema is a relatively common revelation accompanying some diseases such as autoimmune or cancer. The study aimed to assess the incidence of one subtype of angioedema-C1-INH-AAE (acquired angioedema with C1 inhibitor deficiency). Material and methods. The study was retrospective and based on 1 312 patients with a final diagnosis of breast cancer, colorectal cancer, or lung cancer: 723 women and 589 men with a mean age of 58.2 ± 13.5 years. The cancer diagnosis according to the ICD (International Classification of Diseases)-10 code, medical history including TNM (Tumour, Node, Metastasis) staging, histopathology, and assessment of the occurrence of C1-INH-AAE angioedema were analysed. Results. C1-INH-AAE occurred more often in patients with cancer than in the control group, as follows: 327 (29%) vs. 53 (6%) for p < 0.05. C1-INH-AAEs were observed most often in the group of patients diagnosed with breast cancer compared to colorectal and lung groups: 197 (37%) vs. 108 (26%) vs. 22 (16%) (p < 0.05). A higher incidence of C1-INH-AAE was observed in the early stages of breast cancer. However, there was no relationship between the occurrence of C1-INH-AAE and the BRCA1 (Breast Cancer gene 1)/BRCA2 (Breast Cancer gene 2) mutation or histopathological types of breast cancer. Conclusion. Angioedema type C1-INH-AAE occurs more often in patients with selected neoplastic diseases, especially in the early stages of breast cancer.

Hereditary Angioedema: Diagnosis, Clinical Implications, and Pathophysiology

Hereditary angioedema (HAE) is an autosomal dominant disorder caused by a mutation in the C1 esterase inhibitor gene. HAE affects 1/50,000 people worldwide. Three main types of HAE exist: type I, type II, and type III. Type I is characterized by a deficiency in C1-INH. C1-INH is important in the coagulation complement, contact systems, and fibrinolysis. Most HAE cases are type I. Type I and II HAE result from a mutation in the SERPING1 gene, which encodes C1-INH. Formally known as type III HAE is typically an estrogen-dependent or hereditary angioedema with normal C1-INH activity. Current guidelines now recommend subdividing hereditary angioedema with normal C1 esterase inhibitor gene (HAE-nl-C1-INH formerly known as HAE type III) based on underlying mutations such as in kininogen-1 (HAE-KNG1), plasminogen gene (PLG-HAE), myoferlin gene mutation (MYOF-HAE), heparan sulfate-glucosamine 3-sulfotransferase 6 (HS3ST6), mutation in Hageman factor (factor XII), and in angiopoietin-1 (HAE-ANGPT-1). The clinical presentation of HAE varies between patients, but it usually presents with nonpitting angioedema and occasionally abdominal pain. Young children are typically asymptomatic. Those affected by HAE usually present with symptoms in their early 20s. Symptoms can arise as a result of stress, infection, or trauma. Laboratory testing shows abnormal levels of C1-INH and high levels of bradykinin. C4 and D-dimer levels can also be monitored if an acute HAE attack is suspected. Acute treatment of HAE can include IV infusions of C1-INH, receptor antagonists, and kallikrein inhibitors. Short- and long-term prophylaxis can also be administered to patients with HAE. First-line therapies for long-term prophylaxis also include IV infusion of C1-INH. This review aims to thoroughly understand HAE, its clinical presentation, and how to treat it.

Losartan-Induced Angioedema with Acute Hypoxemic Respiratory Failure (Anaphylaxis): A Case Report

Angioedema is a condition characterized by swelling of the skin or mucosa resulting from loss of vascular integrity that leads to swelling of mucosal tissues and can lead to life-threatening respiratory compromise. Drug-induced angioedema is not a frequent side effect seen with angiotensin receptor blockers (ARBs), particularly when there are no other contributing risk factors like a prior episode. Few studies reported subsequent angioedema episodes after ARB use in patients who had a prior episode with angiotensin converting enzyme inhibitors; however, there are very few cases that documented non-fatal angioedema after ARB as the only therapy. We report a rare case of life-threatening anaphylaxis after losartan use. We hope that our case will bring awareness to this rare but fatal side effect in order to quickly recognize it and encourage further research.

Long-term Prophylaxis with Androgens in the management of Hereditary Angioedema (HAE) in emerging countries

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disease characterized by repetitive subcutaneous or submucosal angioedema, activation of the kinin system, and increased vascular permeability. C1-inhibitor (C1-INH) deficiency, the main mechanism of HAE pathogenesis, occurs when abnormal activation of plasma kallikrein, bradykinin, and factor XII, or mutation of genes such as SERPING1 cause quantitative or functional C1-INH defects. Although androgens are not approved for HAE treatment in many countries, they are widely used in China and Brazil to reduce the frequency and severity of HAE attacks. The long-term adverse effects of androgen treatment are concerning for both physicians and patients. Virilization, weight gain, acne, hirsutism, liver damage, headache, myalgia, hematuria, menstrual disorders, diminished libido, arterial hypertension, dyslipidemia, and anxiety/depression are commonly observed during long-term treatment with androgens. These adverse effects can affect the quality of life of HAE patients and often lead to treatment interruption, especially in women and children. In-depth studies of the pathogenesis of HAE have led to the approval of alternative treatment strategies, including plasma-derived C1 inhibitor, recombinant human C1 inhibitor, plasma Kallikrein inhibitor (ecallantide; lanadelumab), and bradykinin B2 receptor antagonist (icatibant), some of which have achieved satisfactory results with mostly non-serious side effects. Therefore, a new standard of medical care may expand possibilities for the management of HAE in emerging countries.

A Comprehensive Review of Bradykinin-Induced Angioedema Versus Histamine-Induced Angioedema in the Emergency Department

Angioedema (AE) is a condition that is frequently encountered in the emergency department (ED). It is a rare condition with localized, asymmetrical swelling of the skin and/or mucosa that is frequently nonpruritic and primarily affects locations with loose connective tissue. Physicians must have a thorough understanding of this condition since it can cause fatal airway compromise, which might be the presenting symptom. Histamine-mediated AE is the most common type of AE seen in EDs. However, ED physicians must be on the lookout for the less common bradykinin-mediated types of AE as these do not respond to the same therapy as histamine-mediated AE. Hospitals may lack specialized drugs or protocols, and many ED staff may be unable to identify or treat bradykinin-mediated AE. It is crucial to understand the pathophysiology of the various kinds of AE in order to optimize treatment. The goal of this review paper is to provide an overview of the pathophysiology, clinical manifestations, and treatment options for bradykinin and histamine-induced AE in the ED.

A catalog of the genetic causes of hereditary angioedema in the Canary Islands (Spain)

Hereditary angioedema (HAE) is a rare disease where known causes involve C1 inhibitor dysfunction or dysregulation of the kinin cascade. The updated HAE management guidelines recommend performing genetic tests to reach a precise diagnosis. Unfortunately, genetic tests are still uncommon in the diagnosis routine. Here, we characterized for the first time the genetic causes of HAE in affected families from the Canary Islands (Spain). Whole-exome sequencing data was obtained from 41 affected patients and unaffected relatives from 29 unrelated families identified in the archipelago. The Hereditary Angioedema Database Annotation (HADA) tool was used for pathogenicity classification and causal variant prioritization among the genes known to cause HAE. Manual reclassification of prioritized variants was used in those families lacking known causal variants. We detected a total of eight different variants causing HAE in this patient series, affecting essentially SERPING1 and F12 genes, one of them being a novel SERPING1 variant (c.686-12A&gt;G) with a predicted splicing effect which was reclassified as likely pathogenic in one family. Altogether, the diagnostic yield by assessing previously reported causal genes and considering variant reclassifications according to the American College of Medical Genetics guidelines reached 66.7% (95% Confidence Interval [CI]: 30.1-91.0) in families with more than one affected member and 10.0% (95% CI: 1.8-33.1) among cases without family information for the disease. Despite the genetic causes of many patients remain to be identified, our results reinforce the need of genetic tests as first-tier diagnostic tool in this disease, as recommended by the international WAO/EAACI guidelines for the management of HAE.

The Interplay of COVID-19 and Hereditary Angioedema: Preventing an Acute Attack

Hereditary angioedema (HAE) is a rare inherited disease that is caused by the inactivation of the C1 esterase inhibitor. In this case report, we present a 51-year-old female previously diagnosed with HAE who tested positive for SARS-Cov-2 (COVID-19). The patient was treated symptomatically. Dexamethasone was used to treat COVID-19 pneumonia. Broad-spectrum antibiotics (vancomycin and meropenem) were utilized to prevent future infection. Although the patient did not experience an acute angioedema attack during her hospital stay, the patient expired due to the exacerbation of COVID-19 pneumonia.

A Rare Case of Dose-Dependent Losartan-Induced Angioedema

Angiotensin converting enzyme inhibitors (ACE-Is) have long been associated with angioedema and cough. These complications are thought to be related to an increase in bradykinin levels. Angiotensin receptor blockers (ARBs) such as losartan, however, are not known to increase bradykinin levels and, therefore, this complication is not as widely recognized. However, there is a significant proportion of patients who develop angioedema on ARB medications after previous episodes of angioedema on ACE-I. Though there is increasing literature to support that the patients may develop angioedema while taking ARBs such as losartan, a dose-dependent nature has not been well documented. We present a patient with a 20-year history of losartan use who developed angioedema suddenly after an increase in dosage. A dose-dependent relationship between ARBs and angioedema has not been well documented and this is the first documented case of angioedema presenting in a dose-dependent manner with losartan use. We hope that our case will bring awareness to the potential dose-dependent relationship between losartan and angioedema in order to aid clinicians when titrating ARB medications in order to expediently diagnose the fatal side-effect of angioedema and to encourage further research.

Hereditary Angioedema: Diagnostic Algorithm and Current Treatment Concepts

Hereditary angioedema (HAE) is an uncommon disorder with a global prevalence of approximately 1 in 10,000 to 1 in 50,000 population. This disease is grossly underrecognized in India because of lack of awareness and/or lack of diagnostic facilities. Clinical manifestations include swelling over face, eyes, lips, hands, feet, and genitals, abdominal pain, and life-threatening laryngeal edema. HAE should be suspected in all patients who present with angioedema without wheals and who do not respond to antihistamines and/or steroids. C1 levels, C1-INH levels, and C1-INH function should be checked in all patients suspected to have HAE. C1q levels should be assessed in patients with suspected autoimmune-mediated acquired angioedema. Management of HAE constitutes the treatment of acute attack and short-term and long-term prophylaxis. Because of lack of all first-line recommended medications, the management of HAE in India is a challenging task. Patients are managed using fresh frozen plasma (acute treatment), tranexamic acid, and attenuated androgens (prophylaxis). Even though attenuated androgens have been shown to be effective in the prevention of attacks of HAE, the side effect profile especially in children and in females is a serious concern. Hence, the treatment needs to be individualized considering the risk-benefit ratio of long-term prophylaxis. In this review, we provide an overview of diagnostic strategy for patients with HAE and the current treatment concepts with emphasis on currently available treatment options in resource-constrained settings.

Hereditary Angioedema: A Gynecology and Obstetrics Perspective

Hereditary angioedema is an autosomal dominant genetic disease that causes tissue edema mediated by bradykinin. The angioedema attacks have several triggers including stress, trauma, infection, and increased estrogens levels. This explains the greater incidence and clinical severity in women, which are usually asymptomatic until puberty, when the attacks begin to occur. It may involve multiple locations on the body, leading to complications, such as surgical intervention prompt by severe acute abdominal pain, and laryngeal edema that can culminate in death from asphyxia. This is of particular concern as this angioedema does not respond to life-saving medications commonly used in its treatment, namely, high doses of second-generation antihistamines, corticosteroids, and epinephrine. Hereditary angioedema attacks are treated with specific medication that includes icatibant, ecallantide, and C1 inhibitor, the latter being also used in short-term and long-term prophylaxis. There are other pharmacological strategies for long-term prophylaxis like lanadelumab, danazol, stanozolol, aminocaproic acid, and tranexamic acid. During pregnancy and lactation, the preferred treatment and prophylaxis is C1 inhibitor.

We report a case of hereditary angioedema describing its chronological evolution over a period of a woman's life, and highlighting some of the specificities of this pathology that intersect with the specialty of Obstetrics and Gynecology. Our aim is to draw attention to these particularities, namely the triggering factors of crisis, the need for high suspicion of the diagnosis, and the treatment and prophylaxis options for pregnant and non-pregnant women that can make the difference between life and death. To achieve a favorable outcome, the multidisciplinary teamwork between the specialties of Immunoallergology and Obstetrics and Gynecology was crucial.

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

Circulating C1q levels in health and disease, more than just a biomarker

C1q is the recognition molecule of the classical pathway of the complement system. By binding to its targets, such as antigen-bound immunoglobulins or C-reactive protein, C1q contributes to the innate defense against infections. However, C1q also plays several other roles beyond its traditional role in complement activation. Circulating levels of C1q are determined in routine diagnostics as biomarker in several diseases. Decreased C1q levels are present in several autoimmune conditions. The decreased levels reflect the consumption of C1q by complement activation and serves as a biomarker for disease activity. In contrast, increased C1q levels are present in infectious and inflammatory diseases and may serve as a diagnostic biomarker. The increased levels of C1q are still incompletely understood but are suggested to modulate the adaptive immune response as C1q is known to impact on the maturation status of antigen-presenting cells and C1q impacts directly on T cells leading to decreased T-cell activity in high C1q conditions. In this review, we provide a comprehensive overview of the current literature on circulating levels of C1q in health and disease, and discuss how C1q can both protect against infections as well as maintain tolerance by regulating adaptive immunity.

First Census of Patients with Hereditary Angioedema in the Canary Islands

Hereditary angioedema (HAE) is a rare genetic condition whose main symptoms are recurrent swelling in the skin, mucosa, and internal organs. Recent studies suggested that the regulation of the inflammatory response and the complement cascade are two of the pathways significantly enriched in the Canary Islands, Spain. Here, we describe the first HAE patient series in this region. Forty-one patients (33 F, 8 M) and nine healthy relatives belonging to twenty-nine families were recruited for this study, obtaining their clinical and demographic features using a data collection form, as well as blood samples for biochemical analysis. The mean age of patients was 36.8 years (ranging from 4 to 72 years). Positive family history of HAE was reported in 13 patients (32.5%), and a mean diagnosis delay of 7.9 (±12.5) years was estimated, ranging from months to 50 years. Cutaneous edema was the most common symptom (53.6%), while airway symptoms was present in 11 patients. Prophylactic treatment was indicated for 23 patients, while 14 also require on-demand rescue treatment. We estimate a minimum prevalence of 1.25:100,000 for HAE due to C1-INH deficiency or dysfunction in the Canary Islands, which is higher than the estimates for mainland Spanish populations. HAE continues to be a disease poorly recognized by health care professionals due to its confusing symptoms, leading to longer diagnosis delay. Altogether, the evidence reinforces the need for a rapid and accurate diagnosis and precision medicine-based studies to improve the patient's quality of life.

Effect of COVID-19 on hereditary angioedema activity and quality of life

Background: The demonstration that severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) enters the cell via the angiotensin-converting enzyme 2 receptor has raised concerns that, in hereditary angioedema (HAE), a disease characterized by bradykinin-mediated angioedema attacks, coronavirus disease 2019 (COVID-19) may trigger angioedema attacks, increase the frequency and/or severity of attacks, or cause more severe symptoms of COVID-19. Objective: The objective was to evaluate the severity of COVID-19 in patients with HAE, the course of HAE attacks, angioedema activity, and the quality-of-life scores during COVID-19 pandemic. Methods: Patients diagnosed with HAE for at least 6 months were included in the study. The 7-day Angioedema Activity Score and the Angioedema Quality of Life (AE-QoL) Questionnaire were first completed at the onset of the pandemic between March 12 and June 1, 2020, then during SARS-CoV-2 infection, and in the third month after recovering from COVID-19. Results: Ten of 67 patients with HAE (14.9%) were diagnosed with COVID-19. The median (interquartile range) age of the 10 patients diagnosed with COVID-19 was 35.5 years (28.0-55.0 years). Six of the 10 patients (60%) were women. During COVID-19, five of the 10 patients (50%) had no angioedema attack. Two patients with severe HAE experienced a significant increase in angioedema activity during COVID-19 compared with their basal activity scores. The remaining three patients had a similar or lower attack frequency than their basal level. Four (40%) of the 10 patients had a relative increase in their attacks during the convalescence period. There was no statistically significant difference among pre-COVID-19, during COVID-19 and post-COVID-19 periods in function, mood, fear and/or shame, nutrition, and total scores of the AE-QoL Questionnaire although the fear dimension was relatively more affected (p = 0.06). Conclusion: Although the sample size was small, analysis of our data supported that the symptoms of COVID-19 were not more severe in HAE. Also, there was no significant difference in the AE-QoL Questionnaire scores, the frequency, and severity of angioedema attacks during the course of COVID-19 in the patients with HAE.

C1-Inhibitor: Structure, Functional Diversity and Therapeutic Development

Human C1-Inhibitor (C1INH), also known as C1-esterase inhibitor, is an important multifunctional plasma glycoprotein that is uniquely involved in a regulatory network of complement, contact, coagulation, and fibrinolytic systems. C1INH belongs to a superfamily of serine proteinase inhibitor (serpins) and exhibits its inhibitory activities towards several target proteases of plasmatic cascades, operating as a major anti-inflammatory protein in the circulation. In addition to its inhibitory activities, C1INH is also involved in non-inhibitory interactions with some endogenous proteins, polyanions, cells and infectious agents. While C1INH is essential for multiple physiological processes, it is better known for its deficiency with regards to Hereditary Angioedema (HAE), a rare autosomal dominant disease clinically manifested by recurrent acute attacks of increased vascular permeability and edema. Since the link was first established between functional C1INH deficiency in plasma and HAE in the 1960s, tremendous progress has been made in the biochemical characterization of C1INH and its therapeutic development for replacement therapies in patients with C1INH-dependent HAE. Various C1INH biological activities, recent advances in the HAE-targeted therapies, and availability of C1INH commercial products have prompted intensive investigation of the C1INH potential for treatment of clinical conditions other than HAE. This article provides an updated overview of the structure and biological activities of C1INH, its role in HAE pathogenesis, and recent advances in the research and therapeutic development of C1INH; it also considers some trends for using C1INH therapeutic preparations for applications other than angioedema, from sepsis and endotoxin shock to severe thrombotic complications in COVID-19 patients.

Novel SERPING1 gene mutations and clinical experience of type 1 hereditary angioedema from North India

BACKGROUND

There is paucity of literature on long-term follow-up of patients with hereditary angioedema (HAE) from developing countries.

OBJECTIVE

This study was carried out to analyze the clinical manifestations, laboratory features, and genetic profile of 32 patients (21 male and 11 female) from 23 families diagnosed with HAE between January 1996 and December 2019.

METHODS

Data were retrieved from medical records of Paediatric Immunodeficiency Clinic, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

RESULTS

Median age at onset of symptoms was 6.25 years (range 1-25 years), and median age at diagnosis was 12 years (range 2-43 years). Serum complement C4 level was decreased in all patients. All patients had low C1-esterase inhibitor (C1-INH) quantitative level (type 1 HAE). SERPING1 gene sequencing could be carried out in 20 families. Of these, 11 were identified to have a pathogenic disease-causing variant in the SERPING1 gene. While 2 of these families had a previously reported mutation, remaining 9 families had novel pathogenic variants in SERPING1 gene. Because of non-availability of C1-INH therapy in India, all patients were given long-term prophylaxis (attenuated androgens or tranexamic acid (TA) or a combination of the 2). Life-threatening episodes of laryngeal edema were managed with fresh-frozen plasma (FPP) infusions. We recorded one disease-related mortality in our cohort. This happened in spite of long-term prophylaxis with stanozolol and TA.

CONCLUSIONS

We report largest single-center cohort of patients with HAE from India. Attenuated androgens, fibrinolytic agents, and FPP may be used for management of HAE in resource-limited settings.

Between two storms, vasoactive peptides or bradykinin underlie severity of COVID-19?

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to be a world-wide pandemic with overwhelming socioeconomic impact. Since inflammation is one of the major causes of COVID-19 complications, the associated molecular mechanisms have been the focus of many studies to better understand this disease and develop improved treatments for patients contracting SARS-CoV-2. Among these, strong emphasis has been placed on pro-inflammatory cytokines, associating severity of COVID-19 with so-called "cytokine storm." More recently, peptide bradykinin, its dysregulated signaling or "bradykinin storm," has emerged as a primary mechanism to explain COVID-19-related complications. Unfortunately, this important development may not fully capture the main molecular players that underlie the disease severity. To this end, in this focused review, several lines of evidence are provided to suggest that in addition to bradykinin, two closely related vasoactive peptides, substance P and neurotensin, are also likely to drive microvascular permeability and inflammation, and be responsible for development of COVID-19 pathology. Furthermore, based on published experimental observations, it is postulated that in addition to ACE and neprilysin, peptidase neurolysin (Nln) is also likely to contribute to accumulation of bradykinin, substance P and neurotensin, and progression of the disease. In conclusion, it is proposed that "vasoactive peptide storm" may underlie severity of COVID-19 and that simultaneous inhibition of all three peptidergic systems could be therapeutically more advantageous rather than modulation of any single mechanism alone.

Acute Presentation of Undiagnosed Hereditary Angioedema of the Larynx: Averting Death

Hereditary angioedema (HAE) differs from histamine-mediated angioedema in that it is resistant to steroids and antihistamines. Laryngeal attacks of this condition, if not diagnosed timely, carry a mortality rate up to 34%. Rarely, this disease goes undiagnosed until late adulthood and presents a life-threatening episode that poses a management challenge to the emergency physician. We report the case of a 48-year-old man who presented to the emergency department with progressive breathing difficulty two hours after consuming a carbonated drink. Clinical examination revealed supraglottic edema. He did not respond to steroids or antihistamines and required emergency tracheostomy to secure the airway due to failed intubation. Absence of symptoms such as itching or urticaria and inadequate response to steroids pointed to hereditary angioedema. Low complement factor 4 levels with low C1 esterase inhibitor functionality confirmed the diagnosis. This case report highlights the fact that delayed presentation of HAE can be life threatening and the diagnosis should be considered in all non-atopic adult patients with angioedema.

Bradykinin System: A Therapeutic Goal for COVID-19

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