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Concept: Angioedema

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Several guidelines for urticaria and angioedema have been published in Europe and United States since 1997. General principles for diagnosis and treatments of them are similar. However, each guideline has its own characteristics and shows differences in areas such as the coverage of urticaria subtypes, nomenclatures, and hierarchy of the medications. In Japan, the Japanese Dermatological Association (JDA) published its first guideline for urticaria and angioedema in 2005. It established a new classification of urticaria and angioedema together with the definition of each subtype. It emphasized the importance of discriminating idiopathic urticaria, consisting of acute urticaria and chronic urticaria from inducible urticaria, such as allergic urticaria, physical urticaria and cholinergic urticaria. It contains several unique algorithms for diagnosis and treatment of urticaria from a view point of clinical practices, and was further enforced by a style of EBM in 2011. Nevertheless, these guidelines have not been recognized outside of Japan, because of a language barrier. In this article, the outline of the newest guidelines by JDA are introduced and compared with the guidelines in other countries published in English.

Concepts: Angioedema, Urticaria, Urticaria and angioedema, Cholinergic urticaria

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Angioedema is the end result of deep dermal, subcutaneous and/or mucosal swelling, and is potentially a life-threatening condition in cases where the pharynx or larynx is involved. Drug-induced angioedema has been reported to occur in response to a wide range of drugs and vaccines. Drug-induced angioedema, like other cutaneous drug reactions, has been reported to be most frequently elicited by beta-lactam antibiotics and non-steroidal anti-inflammatory drugs, although reliable data from epidemiologic studies are scarce. Recent reports suggested an increasing role of angiotensin-converting enzyme inhibitors (ACEIs) in the causation of life-threatening angioedema. ACEI-related angioedema is never accompanied by urticaria and occurs via a kinin-dependent mechanism. ACEI-related angioedema not only can start years after beginning the treatment, but it can then recur irregularly while under that treatment. Furthermore, allergy tests are unreliable for the diagnosis of ACEI-related angioedema, and so the relationship between angioedema and ACEIs is often missed and consequently quite underestimated. Accordingly, better understanding of the kinin-dependent mechanism, which is particular to angioedema, is necessary for the appropriate management of drug-induced angioedema.

Concepts: Pharmacology, Drug, Non-steroidal anti-inflammatory drug, Anti-inflammatory, Drug addiction, Penicillin, Angioedema, ACE inhibitor

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Hereditary angioedema (HAE) is a rare autosomal dominant disease that usually occurs in adolescence and early adulthood. It is characterized by recurrent non-pitting edema involving the skin and intestinal tract, especially the extremities and face. It is not associated with urticaria and pruritus. The cause is known to be the deficiency of C1 inhibitor. We herein report a 7-year-old girl with HAE who had recurrent episodes of swelling of the extremities and face without urticaria and pruritus. Her great grandmother had suffered from the same symptoms. The level of serum C4 was 8.01 mg/dL (normal: 10-40 mg/dL). The level of C1 inhibitor was 5.0 mg/dL (normal: 18-40 mg/dL). To our knowledge, this is the first pediatric case with typical clinical symptoms of HAE and C1 esterase inhibitor deficiency in Korea.

Concepts: Allergy, Gastroenterology, Angioedema, Hereditary angioedema, Urticaria, C1-inhibitor, Cetirizine

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Hereditary angioedema (HAE) is a disease characterized by recurrent tissue swelling affecting various body locations. Recent literature shows that patients with frequent attacks may benefit from long-term prophylaxis. This study evaluated the safety and prophylactic effect of weekly administrations of recombinant C1INH (rhC1INH).

Concepts: Angioedema, Hereditary angioedema, C1-inhibitor

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C1 inhibitor (C1INH) is a single-chain glycoprotein that inhibits activation of the contact system of coagulation and the complement system. C1INH isolated from human blood plasma (pd-hC1INH) is used for the management of hereditary angioedema (HAE), a disease caused by heterozygous deficiency of C1INH, and is a promise for treatment of ischemia-reperfusion injuries like acute myocardial or cerebral infarction. To obtain large quantities of C1INH, recombinant human C1INH (rhC1INH) was expressed in the milk of transgenic rabbits (12g/l) harboring genomic human C1INH sequences fused to 5' bovine αS(1) casein promoter sequences. Recombinant hC1INH was isolated from milk to a specific activity of 6.1U/mg and a purity of 99%; by size-exclusion chromatography the 1% impurities consisted of multimers and N-terminal cleaved C1INH species. Mass spectrometric analysis of purified rhC1INH revealed a relative molecular mass (M®) of 67,200. Differences in M® on SDS PAGE and mass spectrometric analysis between rhC1INH and pd-hC1INH are explained by differential glycosylation (calculated carbohydrate contents of 21% and 28%, respectively), since protein sequencing analysis of rhC1INH revealed intact N- and C-termini. Host-related impurity analysis by ELISA revealed trace amounts of rabbit protein (approximately 10ppm) in purified batches, but not endogenous rabbit C1INH. The kinetics of inhibition of the target proteases C1s, Factor XIIa, kallikrein and Factor XIa by rhC1INH and pd-hC1INH, indicated comparable inhibitory potency and specificity. Recently, rhC1INH (Ruconest(®)) has been approved by the European Medicines Agency for the treatment of acute attacks of HAE.

Concepts: Molecular biology, Blood, Coagulation, Complement system, Glycosylation, Angioedema, Hereditary angioedema, C1-inhibitor

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Introduction: Bradykinin-mediated angioedema is characterized by subcutaneous and/or submucosal edema formation without wheals and pruritus. It is linked to bradykinin-enhanced vascular permeability and, therefore, it does not respond to conventional measures, but requires specific therapy. Areas covered: This summary briefly reviews the different types of bradykinin-mediated angioedema and its remedies. Therapy focuses on relieving edema, as well as on decreasing its incidence and severity. The modes of the actions of attenuated androgens and antifibrinolytics are not precisely known - these agents have been introduced on an empirical basis. Contemporary treatments, by contrast, have been purposely developed to inhibit bradykinin. Most experience pertains to angioedema resulting from C1-inhibitor deficiency, and the controlled studies have focused on the hereditary form of this disease type (HAE). The pathomechanisms of HAE with normal C1-inhibitor activity, as well as of angiotensin-converting enzyme inhibitor-releated, and of non-histaminergic idiopathic sporadic angioedemas are largely unknown. Appropriate laboratory methods for the diagnosis, or specific interventions for the therapy of these conditions are not available or only available off-label. Expert opinion: In this case, diagnosis and management are challenging. The range of targeted therapeutic options has increased in recent years and includes measures to handle emergencies, prevent edematous episodes and manage additional types of bradykinin-mediated angioedema.

Concepts: Allergy, Therapy, Pharmacotherapy, Classification of Pharmaco-Therapeutic Referrals, Angioedema, ACE inhibitor, Edema, Bradykinin

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BACKGROUND AND OBJECTIVE: Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) causes disturbances in the complement system. However, the influence of HAE-C1-INH on the lectin pathway of complement is unresolved. Thus, we studied the main initiator molecules, enzymes and regulators in the lectin pathway in patients with HAE-C1-INH. METHODS: The serum concentrations of ficolin-2, ficolin-3, MBL, MASP-2, MASP-3, and MAP-1 were measured during symptom-free periods in 91 patients with HAE-C1-INH, and in 100 healthy controls using sandwich ELISAs. RESULTS: Compared with controls, the levels of ficolin-2 (p<0.0001) and MASP-2 (p=0.0238) were reduced, while the levels of MBL and MASP-3 were elevated (p=0.0028 and p<0.0001, respectively) in HAE-C1-INH patients. Ficolin-3 and MAP-1 levels did not differ significantly between the two groups. Ficolin-2 correlated with MASP-3 in patients (r=0.3443, p=0.0008), while these parameters showed an opposite relationship in controls (r=-0.4625, p<0.0001). In the patients, ficolin-3 correlated with MASP-2 (r=0.3698, p=0.001). Ficolin-2, -3, and MAP-1 correlated negatively with the annual requirement of plasma derived C1-INH concentrate (r=-0.2863, p=0.0059; r=-0.2654, p=0.0110 and r=-0.2501, p=0.0168, respectively). Ficolin-3 showed a negative correlation with the annual number of attacks (r=-0.2478, p=0.0179). CONCLUSIONS: We found significant differences between patients and controls in the levels of some of the molecules belonging to the lectin complement pathway. Low concentrations of particularly ficolin-2 and -3 were inversely correlated with the severity of HAE-C1-INH, while this was not observed for MBL. This suggests a previously unrecognized involvement of the ficolin-dependent lectin complement pathway in the pathophysiology of HAE-C1-INH.

Concepts: Chemistry, Correlation and dependence, Protease, Complement system, Angioedema, Classical complement pathway, Alternative complement pathway, C1-inhibitor

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Edema is tissue swelling and is a common symptom in a variety of diseases. Edema form due to accumulation of fluids, either through reduced drainage or increased vascular permeability. There are multiple vascular signalling pathways that regulate vessel permeability. An important mediator that increases vascular leak is the peptide hormone bradykinin, which is the principal agent in the swelling disorder hereditary angioedema. The disease is autosomal dominant inherited and presents clinically with recurrent episodes of acute swelling that can be life-threatening involving the skin, the oropharyngeal, laryngeal, and gastrointestinal mucosa. Three different types of hereditary angiodema exist in patients. The review summarises current knowledge on the pathophysiology of hereditary angiodema and focuses on recent experimental and pharmacological findings that have led to a better understanding and new treatments for the disease.

Concepts: Disease, Skin, Angiotensin II receptor antagonist, Angioedema, Hereditary angioedema, ACE inhibitor, Bradykinin, Urticaria

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Background Hereditary angioedema is a disabling, potentially fatal condition caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein. In a phase 2 trial, the use of CSL830, a nanofiltered C1 inhibitor preparation that is suitable for subcutaneous injection, resulted in functional levels of C1 inhibitor activity that would be expected to provide effective prophylaxis of attacks. Methods We conducted an international, prospective, multicenter, randomized, double-blind, placebo-controlled, dose-ranging, phase 3 trial to evaluate the efficacy and safety of self-administered subcutaneous CSL830 in patients with type I or type II hereditary angioedema who had had four or more attacks in a consecutive 2-month period within 3 months before screening. We randomly assigned the patients to one of four treatment sequences in a crossover design, each involving two 16-week treatment periods: either 40 IU or 60 IU of CSL830 per kilogram of body weight twice weekly followed by placebo, or vice versa. The primary efficacy end point was the number of attacks of angioedema. Secondary efficacy end points were the proportion of patients who had a response (≥50% reduction in the number of attacks with CSL830 as compared with placebo) and the number of times that rescue medication was used. Results Of the 90 patients who underwent randomization, 79 completed the trial. Both doses of CSL830, as compared with placebo, reduced the rate of attacks of hereditary angioedema (mean difference with 40 IU, -2.42 attacks per month; 95% confidence interval [CI], -3.38 to -1.46; and mean difference with 60 IU, -3.51 attacks per month; 95% CI, -4.21 to -2.81; P<0.001 for both comparisons). Response rates were 76% (95% CI, 62 to 87) in the 40-IU group and 90% (95% CI, 77 to 96) in the 60-IU group. The need for rescue medication was reduced from 5.55 uses per month in the placebo group to 1.13 uses per month in the 40-IU group and from 3.89 uses in the placebo group to 0.32 uses per month in the 60-IU group. Adverse events (most commonly mild and transient local site reactions) occurred in similar proportions of patients who received CSL830 and those who received placebo. Conclusions In patients with hereditary angioedema, the prophylactic use of a subcutaneous C1 inhibitor twice weekly significantly reduced the frequency of acute attacks. (Funded by CSL Behring; COMPACT EudraCT number, 2013-000916-10 , and ClinicalTrials.gov number, NCT01912456 .).

Concepts: Pharmacology, Clinical trial, Crossover study, Type I and type II errors, Placebo, Randomness, Angioedema, Hereditary angioedema

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Conestat alfa, a recombinant human C1 inhibitor (rhC1-INH) is a novel therapeutic option for the acute treatment of hereditary angioedema due to C1-INH (HAE-C1-INH) deficiency. Our aim was to investigate the efficacy and safety profile of conestat alfa in patients with HAE-C1-INH, under real-life conditions. We analyzed 65 edematous episodes requiring acute treatment and occurring in two female HAE-C1-INH patients. The patients were treated at home with rhC1-INH per occasion. They recorded the time of rhC1-INH administration, the time to the onset of improvement, and time to the complete resolution of symptoms, as well as the side effects. Symptom severity and patient satisfaction were measured with a visual analog scale (VAS). Thirty-three HAE attacks occurred in submucosal tissue, 17 in subcutaneous tissue, and 15 had mixed locations. After the administration of rhC1-INH, clinical symptoms improved within 0.50 (0.17-4.50 hours) hours and resolved completely within 9.00 (1.67-58.75 hours) hours. The time between the onset of the attack and the administration of rhC1-INH was correlated with the time when the symptoms stopped worsening (R = 0.3212; p = 0.0096) and the time to complete resolution of the symptoms (R = 0.4774; p < 0.0001). The time to response to the drug differed with attack location. The efficacy and safety of rhC1-INH persisted after repeated use. None of the patients experienced a recurrence of the HAE attack or drug-related systemic adverse events. The mean VAS score of patient satisfaction was 93.14. Home treatment with rhC1-INH was an effective and well-tolerated therapy for all types of HAE attacks.

Concepts: Symptom, Attack, Angioedema, Hereditary angioedema, Attack!, C1-inhibitor