Tranexamic acid as maintenance treatment for non-histaminergic angioedema: analysis of efficacy and safety in 37 patients

Clinical features and potential markers of disease in idiopathic non-histaminergic angioedema, a real-life study

Idiopathic non-histaminergic acquired angioedema (InH-AAE) is a rare disease, with unknown etiology and pathogenesis, characterized by recurrent clinical manifestations and resistance to antihistamines and corticosteroids. We aim to evaluate clinical features and potential markers of disease in an Italian cohort of patients with InH-AAE. We enrolled 26 patients diagnosed with InH-AAE. Information about clinical features, treatments, routine laboratory investigations, immunological and genetic tests were collected. We assessed plasma levels of complement components, angiogenic and lymphangiogenic mediators, proinflammatory cytokines and chemokines, and activity of phospholipases A2. Finally, patients underwent nailfold videocapillaroscopy (NVC); both quantitative and qualitative capillaroscopic parameters were analyzed. Plasma levels of VEGFs were similar in healthy controls and in InH-AAE patients. ANGPT1 was decreased in InH-AAE patients compared to controls while ANGPT2 was similar to controls. Interestingly, the ANGPT2/ANGPT1 ratio (an index of vascular permeability) was increased in InH-AAE patients compared to controls. sPLA2 activity, elevated in patients with C1-INH-HAE, showed differences also when measured in InH-AAE patients. TNF-α concentration was higher in InH-AAE patients than in healthy controls, conversely, the levels of CXCL8, and IL-6 were similar in both groups. At the NVC, the capillary loops mainly appeared short and tortuous in InH-AAE patients. InH-AAE represents a diagnostic challenge. Due to the potential life-threatening character of this condition, a prompt identification of the potentially bradykinin-mediated forms is crucial. A better comprehension of the mechanism involved in InH-AAE would also lead to the development of new therapeutic approaches to improve life quality of patients affected by this disabling disease.

Tranexamic acid for angiotensin-converting enzyme inhibitor-induced angioedema

Approximately 0.7% of patients taking angiotensin-converting enzyme inhibitors (ACEIs) develop ACEI-induced angioedema (ACEI-IA). With no approved treatments for ACEI-IA, the risk of complications is concerning. Tranexamic acid (TXA) has the potential to prevent intubations and resolve ACEI-IA by inhibiting the downstream production of bradykinin. In this review, we aim to evaluate the safety and efficacy of TXA use in ACEI-IA. We queried the PubMed database for studies involving TXA for ACEI-IA from January 2003 to January 2023. Seven studies met the study inclusion criteria. Our results demonstrate that TXA may improve angioedema symptoms and prevent intubation. In addition, its availability, low cost, and safety profile support its use for improving the symptoms and complications of ACEI-IA in an emergency setting.

A safety review of prophylaxis drugs for adolescent patients with hereditary angioedema

INTRODUCTION

Hereditary angioedema (HAE) is characterized by recurrent subcutaneously and/or submucosally localized edematous swellings. The first symptoms often appear in childhood, and they may become more frequent and severe in puberty. Since the appearance of HAE attacks is unpredictable regarding the localization and the frequency, the attacks put a significant burden on the patients and crucially impacts their quality of life.

AREAS COVERED

This review article analyzes the safety data acquired from the clinical trials conducted with the currently available medicinal products for the prophylactic treatment of hereditary angioedema due to C1 inhibitor deficiency and the safety data of observatory studies based on clinical practice. A review of the published literature was conducted using the PubMed database, clinical trials from ClinicalTrials.gov, and abstracts published at scientific conferences.

EXPERT OPINION

The currently available therapeutic products have a good safety and efficiency profile and the international guidelines recommend them as first-line treatments. The choice should be made based on the evaluation of the availability and the preference of the patient.

Pediatric Angioedema without Wheals: How to Guide the Diagnosis

Angioedema (AE) is a vascular reaction of subcutaneous and submucosal tissues that identifies various clinical pictures and often is associated with wheals. AE without wheals (AEwW) is infrequent. The ability to distinguish between AEwW mediated by mast cells and bradykinin-mediated or leukotriene-mediated pathways is often crucial for a correct diagnostic-therapeutic and follow-up approach. AEwW can be hereditary or acquired. Factors typically correlated with hereditary angioedema (HAE) are a recurrence of episodes, familiarity, association with abdominal pain, onset after trauma or invasive procedures, refractoriness to antiallergic therapy, and lack of pruritus. The acquired forms of AE can present a definite cause based on the anamnesis and diagnostic tests. Still, they can also have an undetermined cause (idiopathic AE), distinguished according to the response to antihistamine in histamine-mediated and non-histamine-mediated forms. Usually, in childhood, AE responds to antihistamines. If AEwW is not responsive to commonly used treatments, it is necessary to consider alternative diagnoses, even for pediatric patients. In general, a correct diagnostic classification allows, in most cases, optimal management of the patient with the prescription of appropriate therapy and the planning of an adequate follow-up.

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.

Hereditary Angioedema During Pregnancy: Considerations in Management

In recent years, hereditary angioedema (HAE) management has substantially advanced but also become more complex with additional therapeutic options. Pregnancy significantly influences the clinical symptoms of HAE in many women because of estrogen effects or other physiologic factors, and also introduces important safety concerns related to HAE medications. Management of HAE during pregnancy requires clinicians to be familiar with the potential clinical course, triggers, and recommended treatment strategies to provide guidance and optimal medical management to women and families affected by the condition. This review provides an overview of data, considerations, and recommendations related to HAE and pregnancy.

Interventions for the long-term prevention of hereditary angioedema attacks

BACKGROUND

Hereditary angioedema (HAE) is a serious and potentially life-threatening condition that causes acute attacks of swelling, pain and reduced quality of life. People with Type I HAE (approximately 80% of all HAE cases) have insufficient amounts of C1 esterase inhibitor (C1-INH) protein; people with Type II HAE (approximately 20% of all cases) may have normal C1-INH concentrations, but, due to genetic mutations, these do not function properly. A few people, predominantly females, experience HAE despite having normal C1-INH levels and C1-INH function (rare Type III HAE). Several new drugs have been developed to treat acute attacks and prevent recurrence of attacks. There is currently no systematic review and meta-analysis that included all preventive medications for HAE.

OBJECTIVES

To assess the benefits and harms of interventions for the long-term prevention of HAE attacks in people with Type I, Type II or Type III HAE.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 3 August 2021.

SELECTION CRITERIA

We included randomised controlled trials in children or adults with HAE that used medications to prevent HAE attacks. The comparators could be placebo or active comparator, or both; approved and experimental drug trials were eligible for inclusion. There were no restrictions on dose, frequency or intensity of treatment. The minimum length of four weeks of treatment was required for inclusion; this criterion excluded the acute treatment of HAE attacks.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. HAE attacks (number of attacks per person, per population) and change in number of HAE attacks; 2. mortality and 3. serious adverse events (e.g. hepatic dysfunction, hepatic toxicity and deleterious changes in blood tests). Our secondary outcomes were 4. quality of life; 5. severity of breakthrough attacks; 6. disability and 7. adverse events (e.g. weight gain, mild psychological changes and body hair). We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified 15 studies (912 participants) that met the inclusion criteria. The studies included people with Type I and II HAE. The studies investigated avoralstat, berotralstat, subcutaneous C1-INH, plasma-derived C1-INH, nanofiltered C1-INH, recombinant human C1-INH, danazol, and lanadelumab for the prevention of HAE attacks. We did not find any studies on the use of tranexamic acid for prevention of HAE attacks. All drugs except avoralstat reduced the number of HAE attacks compared with placebo. For breakthrough attacks that occurred despite prophylactic treatment, intravenous and subcutaneous forms of C1-INH and lanadelumab reduced attack severity. It is not known whether other drugs have a similar effect, as the severity of breakthrough attacks in people taking drugs other than C1-INH and lanadelumab was not reported. For quality of life, avoralstat, berotralstat, C1-INH (all forms) and lanadelumab increased quality of life compared with placebo; there were no data for danazol. Four studies reported on changes in disability during treatment with C1-INH, berotralstat and lanadelumab; all three drugs decreased disability compared with placebo. Adverse events, including serious adverse events, did not occur at a rate higher than placebo. However, serious adverse event data and other adverse event data were not available for danazol, which prevented us from drawing conclusions about the absolute or relative safety of this drug. No deaths were reported in the included studies. The analysis was limited by the small number of studies, the small number of participants in each study and the lack of data on older drugs, therefore the certainty of the evidence is low. Given the rarity of HAE, it is not surprising that drugs were rarely directly compared, which does not allow conclusions on the comparative efficacy of the various drugs for people with HAE. Finally, we did not identify any studies that included people with Type III HAE. Therefore, we cannot draw any conclusions about the efficacy or safety of any drug in people with this form of HAE.

AUTHORS' CONCLUSIONS

The available data suggest that berotralstat, C1-INH (subcutaneous, plasma-derived, nanofiltered and recombinant), danazol and lanadelumab are effective in lowering the risk or incidence (or both) of HAE attacks. In addition, C1-INH and lanadelumab decrease the severity of breakthrough attacks (data for other drugs were not available). Avoralstat, berotralstat, C1-INH (all forms) and lanadelumab increase quality of life and do not increase the risk of adverse events, including serious adverse events. It is possible that danazol, subcutaneous C1-INH and recombinant human C1-INH are more effective than berotralstat and lanadelumab in reducing the risk of breakthrough attacks, but the small number of studies and the small size of the studies means that the certainty of the evidence is low. This and the lack of head-to-head trials prevented us from drawing firm conclusions on the relative efficacy of the drugs.

Clinical manifestations of hereditary angioedema and a systematic review of treatment options

OBJECTIVE

This study systematically reviews the existing literature on the management of hereditary angioedema (HAE) and provides an update on the clinical presentation and specific therapies.

METHODS

A literature search of PubMed and Embase databases was conducted from start of the database to February 2021. Inclusion criteria included relevant systematic reviews, randomized control clinical trials, prospective and retrospective cohort studies, and outcomes research published in English and available in full-text. Out of 310 candidate articles, a total of 55 articles were included in our study.

RESULTS

The most common genetic form of HAE in up to 85% of cases is caused by low levels of C1 esterase inhibitor (C1-INH) protein, leading to a bradykinin-mediated increase in vascular permeability. During an attack of HAE, abortive treatment with C1-INH replacement is most commonly described, however, icatibant, ecallantide, or fresh frozen plasma are also used. Long-term prophylaxis in the form of C1-INH replacement (subcutaneous or intravenous), monoclonal antibodies targeting plasma kallikrein, attenuated androgens, and transexemic acid should be considered for those who suffer from frequent, severe attacks.

CONCLUSION

Progressively distal involvement of the upper airway, especially the larynx, has been shown to pose an increased risk of asphyxiation and death in the acute presentation of HAE. Evaluation by an otolaryngologist is often sought during the emergent clinical management of HAE; therefore, it is prudent that the consulting physician is well-versed in the prompt recognition, triage of patients, and appropriate treatment modalities.

LEVEL OF EVIDENCE

1A.

Assessment and management of disease burden and quality of life in patients with hereditary angioedema: a consensus report

BACKGROUND

Hereditary angioedema (HAE) is a rare disease characterized by unpredictable, potentially life-threatening attacks, resulting in significant physical and emotional burdens for patients and families. To optimize care for patients with HAE, an individualized management plan should be considered in partnership with the physician, requiring comprehensive assessment of the patient's frequency and severity of attacks, disease burden, and therapeutic control. Although several guidelines and consensus papers have been published concerning the diagnosis and treatment of HAE, there has been limited specific clinical guidance on the assessment of disease burden and quality of life (QoL) in this patient population. Practical guidance is critical in supporting effective long-term clinical management of HAE and improving patient outcomes. The objective of this review is to provide evidence-based guidelines for an individualized assessment of disease burden and QoL in patients with HAE.

METHODS

A consensus meeting was held on February 29, 2020, consisting of 9 HAE experts from the United States and Europe with extensive clinical experience in the treatment of HAE. Consensus statements were developed based on a preliminary literature review and discussions from the consensus meeting.

RESULTS

Final statements reflect the consensus of the expert panel and include the assessment of attack severity, evaluation of disease burden, and long-term clinical management of HAE caused by C1-esterase inhibitor deficiency. Patient-reported outcome measures for assessing HAE attack severity and frequency are available and valuable tools; however, attack frequency and severity are insufficient markers of disease severity unless they are evaluated in the broader context of the effect on an individual patient's QoL. QoL assessments should be individualized for each patient and minimally, they should address the interference of HAE with work, school, social, family, and physical activity, along with access to and burden of HAE treatment. Advances in HAE therapies offer the opportunity for comprehensive, individualized treatment plans, allowing patients to achieve minimal attack burden with reduced disease and treatment burden.

CONCLUSION

This consensus report builds on existing guidelines by expanding the assessment of disease burden and QoL measures for patients with HAE.

Clinical characteristics and burden of illness in patients with hereditary angioedema: findings from a multinational patient survey

Background

Hereditary angioedema (HAE) is a rare, debilitating, genetic disease characterized by unpredictable, recurrent, and potentially fatal swelling of the skin and mucous membranes. We conducted a noninterventional, cross-sectional, web-based survey of patients with a self-reported diagnosis of HAE type 1/2 in Australia, Austria, Canada, France, Germany, Spain, Switzerland, and the United Kingdom to gain a comprehensive real-world understanding of the characteristics of HAE and its burden from the perspective of the patient. The survey included questions on clinical and demographic characteristics, burden of disease, and treatment. Instruments used to measure patient-reported outcomes included the Angioedema Quality of Life questionnaire (AE-QoL), 12-Item Short-Form Health Survey (SF-12v2), Angioedema Control Test (AECT), Hospital Anxiety and Depression Scale (HADS), and Work Productivity and Impairment questionnaire (WPAI). Data were analyzed with descriptive statistics.

Results

A total of 242 patients (67.4% female; mean [range] age 43.8 [18–92] years) completed the survey. The mean (SD) age at first symptoms was 11.5 (8.9) years, while diagnosis occurred at 20.8 (13.2) years. Patients reported a mean (SD) of 12.5 (14.1) attacks in the past 6 months. The most recent attack occurred within the past month in 79.7% of patients; most were of moderate severity, 6.6% affected the larynx, 21.9% lasted ≥ 3 days, and 76.4% were treated with on-demand medication. Hospitalizations and emergency/urgent care visits were highest for patients with more attacks. At the time of the survey, 62.4% of patients were using long-term prophylaxis, including 34.4% using androgens. Moderate to severe anxiety and depression were reported in 38.0% and 17.4% of patients, respectively, as measured using the HADS. The severity of anxiety and depression was associated with poorer quality of life and productivity, measured using the AECT (mean overall score 8.00 [moderate perceived disease control]), AE-QoL, WPAI, and SF-12v2. Scores for AECT, AE-QoL, and WPAI were also worse with a higher number of attacks.

Conclusions

This survey study of a broad international sample of patients with HAE showed that despite the availability of on-demand treatment and long-term prophylaxis for the prevention of attacks, patients across a wide geographical area continue to have high disease activity, likely due to restrictions in the availability of medications or incorrect use. Subsequently, significant disease burden, including impaired quality of life and mental health and decreased productivity, was evident. Increased patient education and access to newer, more effective therapies are needed.

Tranexamic acid adverse reactions: a brief summary for internists and emergency doctors

Tranexamic acid (TXA) is a synthetic lysine analogue that is well known as antifibrinolytic agent. It can reduce blood loss in clinical use, especially in conditions where fibrinolysis or hyperfibrinolysis are involved, such as trauma or surgery. Moreover, TXA has been approved as second-line prophylactic therapy for hereditary angioedema and further data have been published about a possible use of TXA as maintenance treatment for nonhistaminergic angioedema and treatment for episodes of bradykinin-mediated angioedema induced by ACE inhibitors. TXA can be administered through several routes: orally, topically, or intravenously. Although, it is a drug with a very high safety profile, in few cases hypersensitivity reactions have been described occurring with different clinical manifestations. Ethamsylate can be an alternative in TXA sensitized patients. In this brief article we describe TXA adverse reactions and current protocols which have been proposed to help clinicians to diagnose TXA hypersensitivity.

Impaired control of the contact system in hereditary angioedema with normal C1-inhibitor

BACKGROUND

Hereditary angioedema (HAE) comprises HAE with C1-inhibitor deficiency (C1-INH-HAE) and HAE with normal C1-INH activity (nl-C1-INH-HAE), due to mutations in factor XII (FXII-HAE), plasminogen (PLG-HAE), angiopoietin 1 (ANGPT1-HAE), kininogen 1 genes (KNG1-HAE), or angioedema of unknown origin (U-HAE). The Italian network for C1-INH-HAE (ITACA) created a registry including different forms of angioedema without wheals.

OBJECTIVE

We analyzed clinical and laboratory features of a cohort of Italian subjects with nl-C1-INH-HAE followed by ITACA to identify specific biomarkers.

METHODS

A total of 105 nl-C1-INH-HAE patients were studied. Plasma concentrations of cleaved high-molecular-weight kininogen (cHK), vascular endothelial growth factors (VEGFs), angiopoietins (Angs), and secreted phospholipase A₂ enzymes (sPLA₂ ) were evaluated.

RESULTS

We identified 43 FXII-HAE patients, 58 U-HAE, and 4 ANGPT1-HAE. We assessed a prevalence of 1:1.4 × 10⁶ for FXII-HAE and 1:1.0 × 10⁶ for U-HAE. cHK levels in U-HAE patients were similar to controls in plasma collected using protease inhibitors cocktail (PIC), but they significantly increased in the absence of PIC. In FXII-HAE patients, cHK levels, in the absence of PIC, were significantly higher than in controls. We found a significant increase of VEGF-A, VEGF-C, and Ang1 levels in U-HAE patients compared to controls. In FXII-HAE, only VEGF-C levels were increased. Ang2 concentrations and sPLA₂ activity were not modified. The levels of these mediators in ANGPT1-HAE patients were not altered.

CONCLUSIONS

Our results suggest that pathogenesis of FXII-, ANGPT1-, and U-HAE moves through an unbalanced control of kallikrein activity, with bradykinin as most likely mediator. VEGFs and Ang1 participate in the pathophysiology of U-HAE increasing the basal vascular permeability.

Pharmacokinetics, Pharmacodynamics, and Exposure-Response of Lanadelumab for Hereditary Angioedema

Hereditary angioedema (HAE) with C1 inhibitor deficiency is a rare disorder characterized by unpredictable, potentially life‐threatening recurrent angioedema attacks. Lanadelumab is a fully human monoclonal antibody with selective binding to active plasma kallikrein, and prevents the formation of cleaved high molecular weight kininogen (cHMWK) and bradykinin, thereby preventing HAE attacks. The clinical pharmacology of lanadelumab was characterized following subcutaneous administration in 257 subjects (24 healthy subjects and 233 patients with HAE). The pharmacokinetics of lanadelumab were described using a one‐compartment model with first‐order rate of absorption and linear clearance, showing slow absorption and a long half‐life (14.8 days). A covariate analysis retained body weight and health status on apparent clearance (CL/F) and body weight on volume of distribution (V/F). Population estimates of CL/F and V/F were 0.0249 L/hour (0.586 L/day) and 12.8 L, respectively. An indirect‐response Imax model showed 53.7% maximum suppression in cHMWK formation with a low potential for interactions with concomitant medications (analgesic, anti‐inflammatory, and antirheumatic medications). A 300 mg dose administered Q2W was associated with a mean steady‐state minimum concentration (C_min,ss; 25.4 μg/mL) that was ~ 4.5‐fold higher than the half‐maximal inhibitory concentration for cHMWK reduction (5.71 μg/mL). Exposure‐response analyses suggest that 300 mg Q2W dosing was associated with a significantly reduced HAE attack rate, prolonged time to first attack after treatment initiation, and lower need for concomitant medications. The response was comparable across patient body weight groups. Findings from this analysis support the dosing rationale for lanadelumab to prevent attacks in patients with HAE.

Idiopathic Angioedema: Current Challenges

The etiological diagnosis of isolated recurrent angioedema poses problems because it must often be done urgently. Angioedema secondary to nonspecific mast cell activation (MC-AE) is the most frequent form and is usually mild. Bradykinin mediated angioedema (BK-AE) is rarer but potentially fatal in the absence of the correct treatment. Few biological markers exist. The C1-inhibitor (C1-inh) functional assay can exclude AE due to C1-inh deficiency. Genetic diagnoses of hereditary AE due to abnormal C1-inh AE have progressed with four currently known mutations. However, determining the physiopathological mechanism leading to some isolated AE cases is sometimes very difficult. In such cases, therapeutic tests are then the only solution: antihistamines at high doses and omalizumab for suspected MC-AE, icatibant for suspected AE-BK. Identifying new markers would be a great help.

The emerging importance of tranexamic acid in dermatology

Tranexamic acid (TA) is an antifibrinolytic agent, increasingly recognized as being of utility for a wide variety of skin diseases. We review the evidence supporting the use of TA for a range of dermatological indications, including (among others) melasma, postinflammatory hyperpigmentation, urticaria, angio-oedema and haemostasis, in addition to practical considerations of its use by dermatologists.

Plasminflammation-An Emerging Pathway to Bradykinin Production

Plasminogen activation is essential for fibrinolysis—the breakdown of fibrin polymers in blood clots. Besides this important function, plasminogen activation participates in a wide variety of inflammatory conditions. One of these conditions is hereditary angioedema (HAE), a rare disease with characteristic attacks of aggressive tissue swelling due to unregulated production and activity of the inflammatory mediator bradykinin. Plasmin was already implicated in this disease decades ago, but a series of recent discoveries have made it clear that plasmin actively contributes to this pathology. Collective evidence points toward an axis in which the plasminogen activation system and the contact system (which produces bradykinin) are mechanistically coupled. This is amongst others supported by findings in subtypes of HAE that are caused by gain-of-function mutations in the genes that respectively encode factor XII or plasminogen, as well as clinical experience with the antifibrinolytic agents in HAE. The concept of a link between plasminogen activation and the contact system helps us to explain the inflammatory side effects of fibrinolytic therapy, presenting as angioedema or tissue edema. Furthermore, these observations motivate the development and characterization of therapeutic agents that disconnect plasminogen activation from bradykinin production.

Structural studies of plasmin inhibition

Plasminogen (Plg) is the zymogen form of the serine protease plasmin (Plm), and it plays a crucial role in fibrinolysis as well as wound healing, immunity, tissue remodeling and inflammation. Binding to the targets via the lysine-binding sites allows for Plg activation by plasminogen activators (PAs) present on the same target. Cellular uptake of fibrin degradation products leads to apoptosis, which represents one of the pathways for cross-talk between fibrinolysis and tissue remodeling. Therapeutic manipulation of Plm activity plays a vital role in the treatments of a range of diseases, whereas Plm inhibitors are used in trauma and surgeries as antifibrinolytic agents. Plm inhibitors are also used in conditions such as angioedema, menorrhagia and melasma. Here, we review the rationale for the further development of new Plm inhibitors, with a particular focus on the structural studies of the active site inhibitors of Plm. We compare the binding mode of different classes of inhibitors and comment on how it relates to their efficacy, as well as possible future developments.

Melkersson-Rosenthal syndrome: a case report of a rare disease with overlapping features

BACKGROUND

Melkersson-Rosenthal syndrome (MRS) is a rare, neuro-mucocutaneous disease which presents as orofacial swelling, facial palsy and fissured tongue. These symptoms may occur simultaneously or, more frequently, with a oligosymptomatic or monosymptomatic pattern. Swelling, that is the most common initial finding, may mimic hereditary or acquired angioedema, a disorder caused by histamine or bradykinin-mediated plasma-leakage affecting subcutaneous and/or submucosal tissue. The differential diagnosis of MRS includes also chronic inflammatory and infective diseases characterized by granulomatous infiltration, as well as rosacea, contact dermatitis, allergic reactions and Bell's palsy.

CASE PRESENTATION

A 71-year old, non-allergic female patient with no familial and personal history of angioedema presented, a few days after a possible herpes simplex or varicella-zoster virus infection, with monolateral facial paraesthesia and lower lip edema. After temporary remission of symptoms on oral steroids and antihistamines, she showed swelling recurrence refractory to valaciclovir therapy and a subsequent course of antihistamines. The clinical picture and a previous history of non-Hodgkin lymphoma prompted us to rule out an acquired form of paraneoplastic, C1-inhibitor (C1-INH) deficiency: C1q and both antigen and functional C1-INH tested normal, whilst we found low plasma levels of C3 and C4 possibly related to the parallel detection of antiphospholipid antibodies. Thus, we hypothesized a non-histaminergic, idiopathic form of angioedema and planned further therapy with tranexamic acid and the leukotriene receptor antagonist montelukast. Treatment failure with both drugs finally suggested a Melkersson-Rosenthal syndrome, which was confirmed by histologic findings of non caseating granulomas on lip biopsy.

CONCLUSION

Melkersson-Rosenthal syndrome may occur with rather non-specific symptoms and overlap with alternative conditions, including recurrent angioedema. No specific biomarkers for MRS exist and clinical diagnosis is often of exclusion. The finding of complement or immune alterations, as in our patient, may be further confounding and justify the need for skin or mucosal biopsy to establish a correct diagnosis and prescribe targeted therapy.

Effect of Lanadelumab Compared With Placebo on Prevention of Hereditary Angioedema Attacks: A Randomized Clinical Trial

IMPORTANCE

Current treatments for long-term prophylaxis in hereditary angioedema have limitations.

OBJECTIVE

To assess the efficacy of lanadelumab, a fully human monoclonal antibody that selectively inhibits active plasma kallikrein, in preventing hereditary angioedema attacks.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, parallel-group, placebo-controlled trial conducted at 41 sites in Canada, Europe, Jordan, and the United States. Patients were randomized between March 3, 2016, and September 9, 2016; last day of follow-up was April 13, 2017. Randomization was 2:1 lanadelumab to placebo; patients assigned to lanadelumab were further randomized 1:1:1 to 1 of the 3 dose regimens. Patients 12 years or older with hereditary angioedema type I or II underwent a 4-week run-in period and those with 1 or more hereditary angioedema attacks during run-in were randomized.

INTERVENTIONS

Twenty-six-week treatment with subcutaneous lanadelumab 150 mg every 4 weeks (n = 28), 300 mg every 4 weeks (n = 29), 300 mg every 2 weeks (n = 27), or placebo (n = 41). All patients received injections every 2 weeks, with those in the every-4-week group receiving placebo in between active treatments.

MAIN OUTCOME AND MEASURES

Primary efficacy end point was the number of investigator-confirmed attacks of hereditary angioedema over the treatment period.

RESULTS

Among 125 patients randomized (mean age, 40.7 years [SD, 14.7 years]; 88 females [70.4%]; 113 white [90.4%]), 113 (90.4%) completed the study. During the run-in period, the mean number of hereditary angioedema attacks per month in the placebo group was 4.0; for the lanadelumab groups, 3.2 for the every-4-week 150-mg group; 3.7 for the every-4-week 300-mg group; and 3.5 for the every-2-week 300-mg group. During the treatment period, the mean number of attacks per month for the placebo group was 1.97; for the lanadelumab groups, 0.48 for the every-4-week 150-mg group; 0.53 for the every-4-week 300-mg group; and 0.26 for the every-2-week 300-mg group. Compared with placebo, the mean differences in the attack rate per month were -1.49 (95% CI, -1.90 to -1.08; P < .001); -1.44 (95% CI, -1.84 to -1.04; P < .001); and -1.71 (95% CI, -2.09 to -1.33; P < .001). The most commonly occurring adverse events with greater frequency in the lanadelumab treatment groups were injection site reactions (34.1% placebo, 52.4% lanadelumab) and dizziness (0% placebo, 6.0% lanadelumab).

CONCLUSIONS AND RELEVANCE

Among patients with hereditary angioedema type I or II, treatment with subcutaneous lanadelumab for 26 weeks significantly reduced the attack rate compared with placebo. These findings support the use of lanadelumab as a prophylactic therapy for hereditary angioedema. Further research is needed to determine long-term safety and efficacy.

TRIAL REGISTRATION

EudraCT Identifier: 2015-003943-20; ClinicalTrials.gov Identifier: NCT02586805.

Hereditary angioedema with C1 inhibitor (C1-INH) deficit: the strength of recognition (51 cases)

Hereditary angioedema (HAE) is a rare autosomal dominant disease due to C1 esterase inhibitor deficiency (C1-INH). The disease is characterized by subcutaneous and submucosal edema in the absence of urticaria due to the accumulation of bradykinin. This descriptive study aimed to evaluate the clinical characteristics of patients with a confirmed diagnosis of HAE referred to our Outpatient Clinic between December 2009 and November 2017. Fifty-one patients (38 F, 13 M) with a mean age of 32 years (range: 7–70 y) were included. Family history of HAE was reported in 70% (36/51) of the cases; 33/46 patients became symptomatic by 18 years of age. The median time between onset of symptoms and diagnosis was 13 years (3 mo–50 y). The most frequent triggering factors for attacks were stress (74.4%), trauma (56.4%), and hormonal variations (56%). The main symptoms were subcutaneous edema in 93.5% (43/46) of patients, gastrointestinal symptoms in 84.8% (39/46), and obstruction in the upper airways in 34.8% (16/46). Hospitalization occurred in 65.2%, of whom 13.3% had to be transferred to the Intensive Care Unit. Prophylactic treatment was instituted in 87% (40/46) of patients, and 56.5% (26/46) required additional treatment to control attacks. Owing to our data collection over a period of 8 years, a significant number of patients were identified by this HAE reference center. Despite early recognition and prophylactic treatment, a high percentage of patients were hospitalized. HAE is still diagnosed late, reinforcing the need for more reference centers specialized in diagnosis and educational projects for health professionals.

Efficacy of Treatment of Non-hereditary Angioedema

Non-hereditary angioedema (AE) with normal C1 esterase inhibitor (C1INH) can be presumably bradykinin- or mast cell-mediated, or of unknown cause. In this systematic review, we searched PubMed, EMBASE, and Scopus to provide an overview of the efficacy of different treatment options for the abovementioned subtypes of refractory non-hereditary AE with or without wheals and with normal C1INH. After study selection and risk of bias assessment, 61 articles were included for data extraction and analysis. Therapies were described for angiotensin-converting enzyme inhibitor-induced AE (ACEi-AE), for idiopathic AE, and for AE with wheals. Described treatments consisted of ecallantide, icatibant, C1INH, fresh frozen plasma (FFP), tranexamic acid (TA), and omalizumab. Additionally, individual studies for anti-vitamin K, progestin, and methotrexate were found. Safety information was available in 26 articles. Most therapies were used off-label and in few patients. There is a need for additional studies with a high level of evidence. In conclusion, in acute attacks of ACEi-AE and idiopathic AE, treatment with icatibant, C1INH, TA, and FFP often leads to symptom relief within 2 h, with limited side effects. For prophylactic treatment of idiopathic AE and AE with wheals, omalizumab, TA, and C1INH were effective and safe in the majority of patients.

Hereditary angioedema: the plasma contact system out of control

The plasma contact system contributes to thrombosis in experimental models. Even though our standard blood coagulation tests are prolonged when plasma lacks contact factors, this enzyme system appears to have a minor (if any) role in hemostasis. In this review, we explore the clinical phenotype of C1 esterase inhibitor (C1-INH) deficiency. C1-INH is the key plasma inhibitor of the contact system enzymes, and its deficiency causes hereditary angioedema (HAE). This inflammatory disorder is characterized by recurrent aggressive attacks of tissue swelling that occur at unpredictable locations throughout the body. Bradykinin, which is considered to be a byproduct of the plasma contact system during in vitro coagulation, is the main disease mediator in HAE. Surprisingly, there is little evidence for thrombotic events in HAE patients, suggesting mechanistic uncoupling from the intrinsic pathway of coagulation. In addition, it is questionable whether a surface is responsible for contact system activation in HAE. In this review, we discuss the clinical phenotype, disease modifiers and diagnostic challenges of HAE. We subsequently describe the underlying biochemical mechanisms and contributing disease mediators. Furthermore, we review three types of HAE that are not caused by C1-INH inhibitor deficiency. Finally, we propose a central enzymatic axis that we hypothesize to be responsible for bradykinin production in health and disease.

Omalizumab for Idiopathic Nonhistaminergic Angioedema: Evidence for Efficacy in 2 Patients

Presently, there is inconclusive evidence regarding the most effective treatment for idiopathic nonhistaminergic acquired angioedema (InH-AAE). Omalizumab may, however, prove to be a promising option. This case report describes two patients who presented with recurrent angioedema attacks, which was refractory to antihistamine therapy. Hence, they were treated with 300 mg omalizumab, every 4 weeks, for a period of 6 months. Both patients had shown a rapid response to the treatment and achieved complete resolution of symptoms without further AE attacks throughout the entire duration of the treatment period. After omalizumab's suspension, one patient remained symptom free for the following 6 months and the other patient had recurrence of symptoms after 2 months for which he was retreated with omalizumab and once again became symptom free. Although omalizumab seems to be effective as a prophylactic treatment for InH-AAE, the determining factors leading to the differences in time-to-relapse between patients after its suspension remain unclear. Further studies are needed in order to better determine the potential therapeutic application of omalizumab and its role in maintenance therapy.

Idiopathic Nonhistaminergic Acquired Angioedema Versus Hereditary Angioedema

BACKGROUND

The mechanism of idiopathic nonhistaminergic acquired angioedema (InH-AAE) has not yet been precisely elucidated. This condition is characterized by recurrent angioedema without wheals.

OBJECTIVE

To study the clinical features of InH-AAE, and to make, for the first time, independent comparisons with hereditary angioedema of unknown origin (U-HAE), as well as with hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE).

METHODS

We compared the clinical parameters of 46 patients with InH-AAE with those of 27 patients suffering from U-HAE, as well as of 73 patients with C1-INH-HAE.

RESULTS

The mean age at the onset of symptoms was 36 years in InH-AAE, 13 years in C1-INH-HAE, and 29 years in U-HAE. More than 12 edematous episodes occurred over a year in 56% of patients with InH-AAE, in 59% of those with C1-INH-HAE, and in 48% of those with U-HAE. Edema of the extremities, of the upper airways, and of the gastrointestinal tract was more common in patients with C1-INH-HAE (92%, 51%, and 75%, respectively). These manifestations occurred less frequently in patients with InH-AAE (54%, 28%, and 20%) and in patients with U-HAE (37%, 29%, and 20%). By contrast, facial edema occurred in only 15% of patients with C1-INH-HAE, but in 67% of patients with InH-AAE and in 59% of patients with U-HAE.

CONCLUSIONS

The clinical manifestations of patients with InH-AAE were different from those of patients with C1-INH-HAE. This may indicate different processes underlying edema formation in these disease forms. The close resemblance of the clinical manifestations in InH-AAE and U-HAE might suggest a similarity between the pathophysiology of these conditions.

Hereditary angioedema with a mutation in the plasminogen gene

BACKGROUND

Hereditary angioedema (HAE) with normal C1-INH (HAEnCI) may be linked to specific mutations in the coagulation factor 12 (FXII) gene (HAE-FXII) or functional mutations in other genes that are still unknown. We sought to identify and characterize a hitherto unknown type of HAE with normal C1-INH and without mutation in the F12 gene.

METHODS

The study comprised analysis of whole-exome sequencing, Sanger sequencing, and clinical data of patients.

RESULTS

We detected a mutation in the plasminogen (PLG) gene in patients with HAEnCI. The mutation c.988A>G was located in exon 9 leading to the missense mutation p.Lys330Glu (K330E) in the kringle 3 domain of the PLG protein. The mutation was identified by next-generation sequencing in 14 patients with HAEnCI belonging to 4 of 7 families. Family studies revealed that this type of HAE was transmitted as an autosomal dominant trait. The PLG gene mutation was present in all studied symptomatic patients and was also found in 9 of 38 index patients from 38 further families with HAEnCI. Most patients had swelling of face/lips (78.3%) and tongue (78.3%). A total of 331 of all 3.795 tongue swellings (8.7%) were associated with dyspnea, voice changes, and imminent asphyxiation. Two women died by asphyxiation due to a tongue swelling.

CONCLUSIONS

Hereditary angioedema with a mutation in the PLG gene is a novel type of HAE. It is associated with a high risk of tongue swellings.

Effect of oral tranexamic acid on macular edema associated with retinal vein occlusion or diabetes

Purpose

Tranexamic acid (TXA) is a widely used antifibrinolytic agent that can also cause a decrease in vascular permeability. We hypothesized that TXA could improve macular edema (ME) that is caused by an increase in retinal vascular permeability. The aim of this study is to evaluate the efficacy of oral TXA for ME associated with retinal vein occlusion (RVO) or diabetic ME (DME).

Patients and methods

Oral TXA (1,500 mg daily for 2 weeks) was administered to patients with persistent ME secondary to RVO (7 eyes) and DME (7 eyes). After 2 weeks (ie, the final day of administration) and 6 weeks (ie, 4 weeks after the final administration), best-corrected visual acuity and central macular thickness (CMT) were measured and compared with baseline. Analyses were performed for RVO and DME cases. No other treatment was performed during the study period.

Results

In RVO cases, significant improvement in CMT was found between baseline (467.7±121.4 μm) and 2-week measurements after treatment (428.7±110.5 μm, p=0.024). No significant change was found in CMT between measurements taken at baseline and 6 weeks after treatment. In DME cases, no significant change was found in CMT between measurements taken at baseline and 2 or 6 weeks after treatment. In all analyses of best-corrected visual acuity, no significant change was observed.

Conclusion

The results support the hypothesis that plasmin plays a role in the development of ME associated with RVO, and oral TXA administration may be useful as an adjuvant treatment when combined with other agents such as anti-vascular endothelial growth factor.

An open-label study to evaluate the long-term safety and efficacy of lanadelumab for prevention of attacks in hereditary angioedema: design of the HELP study extension

BACKGROUND

Hereditary angioedema (HAE) is characterized by recurrent attacks of subcutaneous or submucosal edema. Attacks are unpredictable, debilitating, and have a significant impact on quality of life. Patients may be prescribed prophylactic therapy to prevent angioedema attacks. Current prophylactic treatments may be difficult to administer (i.e., intravenously), require frequent administrations or are not well tolerated, and breakthrough attacks may still occur frequently. Lanadelumab is a subcutaneously-administered monoclonal antibody inhibitor of plasma kallikrein in clinical development for prophylaxis of hereditary angioedema attacks. A Phase 1b study supported its efficacy in preventing attacks. A Phase 3, randomized, double-blind, placebo-controlled, parallel-arm study has been completed and an open-label extension is currently ongoing.

METHODS/DESIGN

The primary objective of the open-label extension is to evaluate the long-term safety of repeated subcutaneous administrations of lanadelumab in patients with type I/II HAE. Secondary objectives include evaluation of efficacy and time to first angioedema attack to determine outer bounds of the dosing interval. The study will also evaluate immunogenicity, pharmacokinetics/pharmacodynamics, quality of life, characteristics of breakthrough attacks, ease of self-administration, and safety/efficacy in patients who switch to lanadelumab from another prophylactic therapy. The open-label extension will enroll patients who completed the double-blind study ("rollover patients") and those who did not participate in the double-blind study ("non-rollover patients"), which includes patients who may or may not be currently using another prophylactic therapy. Rollover patients will receive a single 300 mg dose of lanadelumab on Day 0 and the second dose after the patient's first confirmed angioedema attack. Thereafter, lanadelumab will be administered every 2 weeks. Non-rollover patients will receive 300 mg lanadelumab every 2 weeks regardless of the first attack. All patients will receive their last dose on Day 350 (maximum of 26 doses), and will then undergo a 4-week follow-up.

DISCUSSION

Prevention of attacks can reduce the burden of illness associated with HAE. Prophylactic therapy requires extended, repeated dosing and the results of this study will provide important data on the long-term safety and efficacy of lanadelumab, a monoclonal antibody inhibitor of plasma kallikrein for subcutaneous administration for the treatment of HAE. Trial registration NCT02741596.

Idiopathic non-histaminergic acquired angioedema: a case series and discussion of published clinical trials

Background

Idiopathic non-histaminergic acquired angioedema (InH-AAE) is a rare disease for which there are no available laboratory parameters to clearly define the disorder. Therapy is often difficult and various treatment options have been proposed. In this paper, we have evaluated the most effective therapies for InH-AAE on the basis of current literature and report the therapeutic effect of omalizumab in three patients with InH-AAE.

Methods

Literature was searched with a combination of MeSH/EMTREE terms and freetext search for angioedema and therapy/omalizumab in the databases Medline (Ovid), PubMed/Premedline, Embase, Cochrane library and Scopus with no time or language restrictions. In three patients affected by InH-AAE the therapeutic effect of omalizumab was demonstrated by clinical outcome. In one patient the FcεRI receptor density on basophils was monitored under therapy with omalizumab.

Results

From the review of the current literature, 25 out of 286 publications dealing with relevant therapeutic recommendations for InH-AAE were analyzed. Six publications with 98 patients referred to tranexamic acid, of which 27 had a complete, 70 a partial and 1 no response. In three case reports ecallantide showed 2 patients with a complete and 1 a partial response. In four case reports for Icatibant 2 had a complete and 3 a partial response. When evaluated in three reports, C1-INH found complete and partial responses in 2 patients each. One patient had a complete response to progestin. Omalizumab was described in 6 reports with 20 patients, all of whom showed a complete response. All three patients described in our study responded to omalizumab with a complete remission. Density of FcεRI receptors on basophils, monitored in patient 1 on a long-term course of 31 months, decreased from 74,051.61 to a minimal level of 1907 receptors per cell.

Conclusions

Omalizumab seems to be the most effective therapy in InH-AAE. The continuous decrease of FcεRI-receptor density on basophils under therapy with omalizumab along with clinical improvement observed in one patient, could serve as a new approach for further studies to evaluate FcεRI-receptor density as a surrogate marker for therapeutic efficacy and for dosing and determining injection intervals of omalizumab.

Trial registration BASEC-Nr. Req-2016-00692. Retrospectively registered 24.11.2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0164-9) contains supplementary material, which is available to authorized users.

An Update on the Use of Immunomodulators in Primary Immunodeficiencies

The genomic revolution in the past decade fuelled by breathtaking advances in sequencing technologies has defined several new genetic diseases of the immune system. Many of these newly characterized diseases are a result of defects in genes involved in immune regulation. The discovery of these diseases has opened a vista of new therapeutic possibilities. Immunomodulatory agents, a hitherto unexplored therapeutic option in primary immunodeficiency diseases have been tried in a host of these newly described maladies. These agents have been shown conclusively to favorably modulate immune responses, resulting in abatement of clinical manifestations both in experimental models and patients. While some of the treatment options have been approved for therapeutic use or have been shown to be of merit in open-label trials, others have been shown to be efficacious in a handful of clinical cases, animal models, and cell lines. Interferon γ is approved for use in chronic granulomatous disease (CGD) to reduce the burden of infection and and has a good long-term efficacy. Recombinant human IL7 therapy has been shown increase the peripheral CD4 and CD8 T cell counts in patients with idiopathic CD4. Anti-IL1 agents are approved for the management of cryopyrin-related autoinflammatory syndrome, and their therapeutic efficacy is being increasingly recognized in other autoinflammatory syndromes and CGD. Mammalian target of rapamycin (mTOR) inhibitors have been proven useful in autoimmune lymphoproliferative syndrome (ALPS) and in IPEX syndrome. Therapies reported to be potential use in case reports include abatacept in CTLA4 haploinsufficiency and LRBA deficiency, ruxolitinib in gain-of-function STAT1, tocilizumab in gain-of-function STAT3 defect, mTOR inhibitors in PIK3CD activation, magnesium in XMEN syndrome, and pioglitazone in CGD. Treatment options of merit in human cell lines include interferon α and interferon β in TLR3 and UNC-93B deficiencies, anti-interferon therapy in SAVI, and Rho-kinase inhibitors in TTC7A deficiency. Anti-IL17 agents have show efficacy in animal models of leukocyte adhesion defect (LAD) and ALPS. This topical review explores the use of various immunomodulators and other biological agents in the context of primary immunodeficiency and autoinflammatory diseases.

Treatment for hereditary angioedema with normal C1-INH and specific mutations in the F12 gene (HAE-FXII)

Hereditary angioedema with normal C1 esterase inhibitor and mutations in the F12 gene (HAE-FXII) is associated with skin swellings, abdominal pain attacks, and the risk of asphyxiation due to upper airway obstruction. It occurs nearly exclusively in women. We report our experience treating HAE-FXII with discontinuation of potential trigger factors and drug therapies. The study included 72 patients with HAE-FXII. Potential triggers included estrogen-containing oral contraceptives (eOC), hormonal replacement therapy, or angiotensin-converting enzyme inhibitors. Drug treatment comprised plasma-derived C1 inhibitor (pdC1-INH) for acute swelling attacks and progestins, tranexamic acid, and danazol for the prevention of attacks. Discontinuation of eOC was effective in 25 (89.3%) of 28 women and led to a reduction in the number of attacks (about 90%). After ending hormonal replacement therapy, three of eight women became symptom-free. Three women with exacerbation of HAE-FXII during intake of quinapril or enalapril had no further HAE-FXII attacks after discontinuation of those drugs. Eleven women were treated with pdC1-INH for 143 facial attacks. The duration of the treated facial attacks (mean: 26.6 h; SD: 10.1 h) was significantly shorter than that of the previous 88 untreated facial attacks in the same women (mean: 64.1 h; SD: 28.0 h; P < 0.01). The mean reduction in attack frequency was 99.8% under progestins after discontinuing eOC (16 women), 93.8% under tranexamic acid (four women), and 100% under danazol (three women). For patients with HAE-FXII, various treatment options are available which completely or at least partially reduce the number or duration of attacks.

Idiopathic Non-histaminergic Angioedema: Successful Treatment with Omalizumab in Five Patients

Idiopathic non-histaminergic acquired angioedema (InH-AAE) is a rare disease characterized by AE resistant to antihistamines and a chronic course. We report five new cases of InH-AAE (two women and three men) with a rapid and dramatic response to the anti-immunoglobulin-E antibody omalizumab. In our literature review, we found 13 other relevant cases with a good response to this treatment. Overall, in 6 out of 18 patients, the doses of omalizumab required to prevent recurrences of attacks were higher than the licensed dose for chronic urticaria. No significant adverse effects have been reported.

Factor XII: form determines function

Factor XII is a mysterious plasma protein without a clear physiologic function. It was identified as a clotting factor, but has no clear role in hemostasis. However, FXII also contributes to the production of bradykinin, a short-lived inflammatory peptide. A growing body of mechanistic research from animal models indicates that FXII contributes to thrombotic disease by triggering excessive coagulation. FXII is evolutionarily conserved, suggesting that this molecule does have a physiologic function. This leads to intriguing questions: What does FXII really do? Is it even a real clotting factor at all? Before the groundbreaking discovery of a role for FXII in thrombotic disease, many studies investigated the biochemical properties of FXII and its activators. In this review, we highlight several biochemical studies that reveal much about the natural behavior of FXII. On the basis of these findings, it is possible to draft a conceptual model to explain how FXII reacts to surface materials. We then discuss how this model applies to the activities of FXII in its natural environment. There are two tentative physiologic functions of FXII that can operate exclusively: (i) maintenance of thrombus stability; (ii) local regulation of vascular permeability. Either, or both, of these natural functions may explain the evolutionary development and maintenance of FXII.

Pharmacologic Therapies in Pulmonology and Allergy

Conditions such as chronic rhinitis, urticaria, angioedema, and asthma are frequently seen in clinics and hospitals, and there are a core group of medications that are often used to treat these conditions. Knowing the indications, optimal dosing, and side-effect profile of these medications can improve outcomes. Chronic rhinitis due to various causes is one of the most common reasons for primary care physician visits. Knowing the indications for use, forms of administration, and side-effect profiles of these medications can help improve patient outcomes in these common conditions. This review focuses on the medications used to treat these conditions.

Current treatment options for idiopathic angioedema

BACKGROUND

Idiopathic angioedema is defined as localized swelling of the cutaneous and mucosal tissue that occurs in episodes without a clear etiology. It can be problematic to treat when the underlying pathophysiology is not well understood.

OBJECTIVE

To identify successful treatments of idiopathic angioedema reported in the literature.

METHODS

A literature search was performed using PubMed. Published case reports and articles discussing treatment of idiopathic angioedema were used in the formulation of this review. In addition, 2 case reports are provided.

RESULTS

Although there are no approved treatments for idiopathic angioedema, several medications used for the treatment of hereditary angioedema, such as bradykinin receptor antagonists (icatibant), kallikrein inhibitors (ecallantide), and C1 inhibitors, were successful in 10 patients. Anti-IgE monoclonal antibody (omalizumab) proved successful in 5 patients. The most widely used and successful medication was tranexamic acid (154 patients).

CONCLUSION

Despite an unknown etiology, this article highlights viable treatment options for idiopathic angioedema. More clinical trials and better markers identifying the cause of angioedema are needed.

Differential Diagnosis and Management Issues of Idiopathic Angiooedema and their Resolution

Angiooedema is a local and self-limiting swelling of the subcutaneous and sub mucosal tissues, produced by vasoactive peptides that temporary increase the vascular permeability. It is recognized that recurrent angiooedema exposes patients to the risk of fatalities and reduced quality of life, being in some circumstances associated with a critical condition. Angiooedema can occur with or without wheals. The first symptom is urticaria, the second is a distinct nosologic entity. In absence of an identifiable cause, recurrent angiooedema without wheals can be defined as idiopathic and marked"idiopathic histaminergic angiooedema" when it is responsive to anti histamine treatment, and "idiopathic non-histaminergic angiooedema" when it is not. Furthermore, idiopathic non-histaminergic angiooedema can be diagnosed as hereditary or sporadic by family history. In this review, we summarize the approaches to diagnose and treat different forms of idiopathic angiooedema.

Characterization of patients with angioedema without wheals: the importance of F12 gene screening

Sporadic and familiar forms of non-histaminergic angioedema and normal C1 inhibitor encompass a group of disorders possibly caused by bradikinin. We aimed to study the subgroups of hereditary angioedema with FXII mutation (FXII-HAE), unknown genetic defect (U-HAE) and idiopathic non-histaminergic acquired angioedema (InH-AAE). We screened the F12 locus in our cohort and delineated the clinical, laboratory and genetic features. Four families carried the p.Thr309Lys mutation in F12 gene. Haplotyping confirmed the hypothesis of a common founder. Six families were affected by U-HAE and 13 patients by sporadic InH-AAE. C4 levels were significantly lower in FXII-HAE than in InH-AAE. In the FXII-HAE group, none had attacks exclusively in high estrogenic states; acute attacks were treated with icatibant. Prophylaxis with tranexamic acid reduced the attack frequency in most patients. Our study provides new data on the diagnosis, clinical features and treatment of non-histaminergic angioedema, underlying the role of the screening for F12 mutations.