Danazol and stanozolol in long-term prophylactic treatment of hereditary angioedema

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.

The international WAO/EAACI guideline for the management of hereditary angioedema - The 2021 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2), by providing guidance on common and important clinical issues, such as: 1) How should HAE be diagnosed? 2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? 3) What are the goals of treatment? 4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast feeding women? 5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

Attenuated androgen discontinuation in patients with hereditary angioedema: a commented case series

Background

Hereditary angioedema (HAE) is characterized by potentially severe and life-threatening attacks of localized swelling. Prophylactic therapies are available, including attenuated androgens. Efficacy of attenuated androgens has not been assessed in large, randomized, placebo-controlled trials and can be associated with frequent, and sometimes severe, side effects. As better tolerated targeted therapies become available, attenuated androgen withdrawal is increasingly considered by physicians and their patients with HAE. Attenuated androgens withdrawal has not been systematically studied in HAE, although examination of other disorders indicates that attenuated androgen withdrawal may result in mood disturbances and flu-like symptoms. Standardized protocols for attenuated androgen discontinuation that continue to provide control of attacks while limiting potential attenuated androgen withdrawal symptoms are not established as the outcomes of different withdrawal strategies have not been compared. We aim to describe the challenges of attenuated androgen discontinuation in patients with HAE and how these may continue into the post-androgen period.

Case presentation

We present a retrospective case series of 10 patients with confirmed type I HAE who have discontinued prophylactic treatment with attenuated androgens. The most common reason for attenuated androgen discontinuation was side effects. Attenuated androgens were either immediately withdrawn, tapered and/or overlapped with another treatment. The major challenge of discontinuation was the management of an increased frequency and severity of HAE attacks in some patients.

Conclusions

Healthcare teams need to undertake careful planning and monitoring after attenuated androgens discontinuation, and modify treatment strategies if HAE control is destabilized with an increased number of attacks. Discontinuation of attenuated androgens is definitively an option in an evolving HAE treatment landscape, and outcomes can be favourable with additional patient support and education.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00644-0.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2021 revision and update

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

Critical appraisal of androgen use in hereditary angioedema: a systematic review

OBJECTIVE

To provide an objective basis for evaluating the risk-benefit ratio of long-term androgen use in patients with hereditary angioedema (HAE).

DATA SOURCES

PubMed was searched with no time limitations using the keywords hereditary angioedema or angio-oedema combined with danazol, stanozolol, and androgen.

STUDY SELECTION

Qualifying articles were English-language reports of androgen use in patients with HAE, with relevant safety and/or efficacy information. Reports were categorized according to level of evidence (LOE).

RESULTS

The search process identified 153 citations, 63 of which contained relevant information; 2 additional publications were identified while other citations were being reviewed. Fifteen LOE 2 studies and multiple LOE 4 reports provided efficacy data, confirming a high level of prophylactic efficacy for androgen therapy in HAE, with occasional reports of poor prophylactic response. Common adverse events include weight gain, menstrual irregularities, virilization, headaches, myalgias or cramps, mood changes, and elevations in creatine phosphokinase level, liver function test results, and serum lipid level. The risk of adverse events is often correlated with dose and/or treatment duration. Rare cases of hepatic adenomas and hepatocellular carcinoma associated with long-term androgen use often had no preceding changes in liver function test results.

CONCLUSION

Androgen therapy may be effective for most patients with HAE; however, potential risks and adverse effects must be carefully considered and discussed with patients when considering options for long-term HAE prophylaxis.

Hereditary angioedema caused by c1-esterase inhibitor deficiency: a literature-based analysis and clinical commentary on prophylaxis treatment strategies

Hereditary angioedema (HAE) caused by C1-esterase inhibitor deficiency is an autosomal-dominant disease resulting from a mutation in the C1-inhibitor gene. HAE is characterized by recurrent attacks of intense, massive, localized subcutaneous edema involving the extremities, genitalia, face, or trunk, or submucosal edema of upper airway or bowels. These symptoms may be disabling, have a dramatic impact on quality of life, and can be life-threatening when affecting the upper airways. Because the manifestations and severity of HAE are highly variable and unpredictable, patients need individualized care to reduce the burden of HAE on daily life. Although effective therapy for the treatment of HAE attacks has been available in many countries for more than 30 years, until recently, there were no agents approved in the United States to treat HAE acutely. Therefore, prophylactic therapy is an integral part of HAE treatment in the United States and for selected patients worldwide. Routine long-term prophylaxis with either attenuated androgens or C1-esterase inhibitor has been shown to reduce the frequency and severity of HAE attacks. Therapy with attenuated androgens, a mainstay of treatment in the past, has been marked by concern about potential adverse effects. C1-esterase inhibitor works directly on the complement and contact plasma cascades to reduce bradykinin release, which is the primary pathologic mechanism in HAE. Different approaches to long-term prophylactic therapy can be used to successfully manage HAE when tailored to meet the needs of the individual patient.

WAO Guideline for the Management of Hereditary Angioedema

Hereditary Angioedema (HAE) is a rare disease and for this reason proper diagnosis and appropriate therapy are often unknown or not available for physicians and other health care providers. For this reason we convened a group of specialists that focus upon HAE from around the world to develop not only a consensus on diagnosis and management of HAE, but to also provide evidence based grades, strength of evidence and classification for the consensus. Since both consensus and evidence grading were adhered to the document meets criteria as a guideline. The outcome of the guideline is to improve diagnosis and management of patients with HAE throughout the world and to help initiate uniform care and availability of therapies to all with the diagnosis no matter where the residence of the individual with HAE exists.

Evidence-based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group

Angioedema owing to hereditary deficiency of C1 inhibitor (HAE) is a rare, life-threatening, disabling disease. In the last 2 years, the results of well-designed and controlled trials with existing and new therapies for this condition have been published, and new treatments reached the market. Current guidelines for the treatment for HAE were released before the new trials and before the new treatments became available and were essentially based on observational studies and expert opinion. To provide evidence-based HAE treatment guidelines supported by the new studies, a conference was held in Gargnano del Garda, Italy, from September 26 to 29, 2010. The meeting hosted 58 experienced HAE expert physicians, representatives of pharmaceutical companies and representatives of HAE patients' associations. Here, we report the topics discussed during the meeting and evidence-based consensus about management approaches for HAE in adult/adolescent patients.

Migraine-like headache in a patient with complement 1 inhibitor deficient hereditary angioedema

We report on an angioedema patient with a genetic defect in complement 1 inhibitor, manifesting migraine-like episodes of headache, effective prophylaxis with Danazol, and triptan for a treatment of acute clinical episode. The patient was 44-yr-old Korean man with abdominal pain and headache, who was brought into the Emergency Department of Seoul National University Hospital, Seoul. He suffered from frequent attacks of migraine-like headache (3-7 per month), pulsating in nature associated with nausea. Severities were aggravated by activity and his headache had shown recent progression with abdominal pain. No remarkable findings were observed on radiologic examination, brain magnetic resonance images and intracranial and extracranial magnetic resonance angiography. Danazol 200 mg every other day was subsequently used. Following administration of Danazol, symptoms showed improvement and the patient was discharged. While taking Danazol, the migraine-like episodes appeared to be prevented for about 2 yr. At the eighth month, he suffered a moderate degree of migraine-like headache; however, administration of naratriptan 2.5 mg resolved his problem. A case of genetic defect of C1-INH deficiency presented with headache episodes, and was controlled by Danazol and triptan. It suggests that pathogenic mechanism of headache in hereditary angioedema may be mediated by the neurogenic inflammatory-like physiology of migraine.

Long-term prophylaxis in hereditary angio-oedema: a systematic review

OBJECTIVE

To systematically review the evidence regarding long-term prophylaxis in the prevention or reduction of attacks in hereditary angio-oedema (HAE).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Electronic databases were searched up to April 2011. Two reviewers selected the studies and extracted the study data, patient characteristics and outcomes of interest.

ELIGIBILITY CRITERIA FOR SELECTED STUDIES

Controlled trials for HAE prophylaxis.

RESULTS

7 studies were included, for a total of 73 patients and 587 HAE attacks. Due to the paucity of studies, a meta-analysis was not possible. Since two studies did not report the number of HAE attacks, five studies (52 patients) were finally included in the summary analysis. Four classes of drugs with at least one controlled trial have been proposed for HAE prophylaxis. All those drugs, except heparin, were found to be more effective than placebo. In the absence of direct comparisons, the relative efficacies of these drugs were determined by calculating a RR of attacks (drug vs placebo). The results were as follows: danazol (RR=0.023, 95% CI 0.003 to 0.162), methyltestosterone (RR=0.054, 95% CI 0.013 to 0.163), ε-aminocaproic acid (RR=0.095, 95% CI 0.025 to 0.356), tranexamic acid (RR=0.308, 95% CI 0.195 to 0.479) and C1-INH 0.491 (95% CI 0.395 to 0.607).

CONCLUSIONS

Few trials have evaluated the benefits of HAE prophylaxis, and all drugs but heparin seem to be effective in this setting. Since there are no direct comparisons of HAE drugs, it was not possible to draw definitive conclusions on the most effective one. Thus, to accumulate evidence for HAE prophylaxis, further studies are needed that consider the dose-efficacy relationship and include a head-to-head comparison between drugs, with the active group, rather than placebo, as the control.

New therapeutics in C1INH deficiency: a review of recent studies and advances

Hereditary angioedema (HAE) is a genetic condition causing a significant burden of illness for affected individuals. Episodes of angioedema involving the skin, gastrointestinal tract, as well as the larynx and oropharynx are often unpredictable and cause significant morbidity and mortality. Isolation of the underlying protein deficiency, specifically the serine protease C1 inhibitor, and further description of its role in multiple physiologic cascades has led to the development of several specific therapies for HAE. This report provides a brief overview of HAE but focuses primarily on reviewing recently published clinical studies of therapeutics developed for medical management of the condition.

Conestat alfa for the treatment of angioedema attacks

Recently, multiple C1 inhibitor (C1-INH) replacement products have been approved for the treatment of hereditary angioedema (HAE). This review summarizes HAE and its current treatment modalities and focuses on findings from bench to bedside trials of a new C1-INH replacement, conestat alfa. Conestat alfa is unique among the other C1-INH replacement products because it is produced from transgenic rabbits rather than derived from human plasma donors, which can potentially allow an unlimited source of drug without any concern of infectious transmission. The clinical trial data generated to date indicate that conestat alfa is safe and effective for the treatment of acute HAE attacks.

Long-term efficacy of danazol treatment in hereditary angioedema

BACKGROUND

No systematic study has been published yet on the long-term efficacy of attenuated androgens in hereditary angioedema (HAE). Our aim was to conduct a follow-up study in two (German and Hungarian) cohorts of HAE patients (45 and 39 patients, respectively) undergoing uninterrupted treatment for 6 years with similar (starting dose 128 ± 78 mg per day and 136 ± 70 mg per day, respectively) and constant doses of danazol.

DESIGN

The frequencies of subcutaneous, abdominal and laryngeal attacks were recorded each year.

RESULTS

The annual frequency of all the three types of attacks was significantly lower during the first year of danazol treatment, compared to the last year before baseline. During subsequent years in Hungarian patients, the frequency of both subcutaneous and abdominal attacks - but not that of laryngeal attacks - increased significantly. In the case of abdominal attacks, a significant increase in the attack frequency was observed only in female patients. In the German cohort, by contrast, no change in the frequency of either type of attack was found during the 6-year study period.

CONCLUSIONS

The differences observed between these cohorts cannot be related to drug dose, the age or gender distribution of subjects or the age at the onset of symptoms or the length of diagnostic delay in the patients. There were, however, marked differences in the baseline pattern of attacks: significantly - 3 times - more abdominal attacks were recorded in German patients. Further studies are necessary to clarify the mechanism of these findings.

Long-term prophylaxis of hereditary angioedema with androgen derivates: a critical appraisal and potential alternatives

Androgen derivatives are regarded as standard in the long-term prophylaxis of swelling attacks in patients with hereditary angioedema (HAE). Because of their relatively slow onset of action, they are not suitable for acute therapy. Long-term prophylaxis with androgen derivatives must be regarded critically, especially on account of their androgenic and anabolic effects, some of which are severe. The risk of adverse events increases with the daily dose and the duration of treatment. Thus, treatment always calls for close monitoring of patients with regard to potential adverse events. In addition, androgens are subject to numerous contraindications and they show interactions with a large number of other drugs. Off-label use, doping issues, clarification of reimbursement and the need to import the androgen derivatives, which are no longer marketed in Germany, result in additional effort for the treating physician in terms of logistics and time involved. In symptomatic treatment of acute attacks the intravenous substitution of C1-INH and - since 2008 - subcutaneous administration of icatibant are available. The two substances are well tolerated and their effect occurs rapidly and, when the diagnosis has been confirmed, reliably. In the light of these two treatment options for controlling acute attacks, prophylactic treatment of HAE patients with androgen derivatives such as danazol should be reassessed. Patients might benefit from a dose reduction or the withdrawal of androgen prophylaxis and attacks can be controlled with demand-oriented acute treatment using C1-INH or icatibant.

Hereditary angioedema: an update on available therapeutic options

There is no cure for hereditary angioedema (HAE). Therapeutic approaches consist of symptomatic therapy for acute attacks, short-term prophylaxis before surgery, and long-term prophylaxis for those with frequent and severe attacks. In Germany, C1-INH concentrate and icatibant are licensed for acute therapy. C1-INH concentrate, which is obtained from human plasma, is administered intravenously to restore the deficient C1-INH activity. This therapy, which has been available for decades, is effective and well-tolerated. Batch documentation is required by German law. The synthetic decapeptide icatibant is administered subcutaneously. It competes with bradykinin, the responsible inducer of edema formation, for binding to the bradykinin B2 receptor. Icatibant is also effective and well-tolerated, even on repeated administration. An additional human C1-inhibitor, a recombinant human C1-inhibitor and the recombinant inhibitor of kallikrein ecallantide are currently under development. There are no licensed treatment options available in Germany for long- and short-term prophylaxis. Androgen derivatives are established in long-term prophylaxis. However, they are associated with many adverse effects, some of which are severe. Many drug interactions also limit their use. They are contraindicated in pregnancy, lactation, for children and in cases of prostate cancer. Antifibrinolytics have fewer adverse effects but are also less effective than androgens. They are contraindicated in thromboembolic disease and impaired vision. If androgen therapy has too negative an effect on quality of life, it may be worth reducing the dose or discontinuing therapy entirely and treating attacks with acute therapy.

Current and emerging management options for hereditary angioedema in the US

Hereditary angioedema (HAE) is a rare disorder characterized by recurrent attacks of swelling that may involve multiple anatomical locations. In the majority of patients, it is caused by a functional or quantitative defect in the C1 inhibitor (C1-INH), which is an important regulator of the complement, fibrinolytic, kallikrein-kinin and coagulation systems. Standard treatments used for other types of angioedema are ineffective for HAE. Traditional therapies for HAE, including fresh frozen plasma, epsilon-aminocaproic acid and danazol, may be well tolerated and effective in some patients; however, there are limitations both in their safety and efficacy. Several novel therapies have completed phase III trials in the US, including: (i) plasma-derived C1-INH replacement therapies (Berinert P and Cinryze); (ii) a recombinant C1-INH replacement therapy (conestat alfa; Rhucin); (iii) a kallikrein inhibitor (ecallantide [DX-88]); and (iv) a bradykinin-2-receptor antagonist (icatibant). Both Berinert P and Cinryze are reported to have excellent efficacy and safety data from phase III trials. Currently, only Cinryze has been approved for prophylactic use in the US. US FDA approval for other novel agents to treat HAE and for the use of Cinryze in the treatment of acute attacks is pending.

C1 inhibitor: just a serine protease inhibitor? New and old considerations on therapeutic applications of C1 inhibitor

C1 inhibitor is a potent anti-inflammatory protein as it is the major inhibitor of proteases of the contact and the complement systems. C1-inhibitor administration is an effective therapy in the treatment of patients with hereditary angioedema (HAE) who are genetically deficient in C1 inhibitor. Owing to its ability to modulate the contact and complement systems and the convincing safety profile, plasma-derived C1 inhibitor is an attractive therapeutic protein to treat inflammatory diseases other than HAE. In the present review we give an overview of the biology of C1 inhibitor and its use in HAE. Furthermore, we discuss C1 inhibitor as an experimental therapy in diseases such as sepsis and myocardial infarction.

Anti-cholesterol antibody levels in hereditary angioedema

Hereditary angioedema (HAE) is a rare disorder caused by the deficiency of the C1-inhibitor gene (C1INH) and characterized by recurrent bouts of angioedema. Autoimmune disorders frequently occur in HAE. Previously we found, that danazol has an adverse effect on serum lipid profile: reduced high-density lipoprotein (HDL) and elevated low-density lipoprotein (LDL) cholesterol levels are associated with long-term prophylactic use, whereas total cholesterol levels are unchanged. Our aim was to study the anti-cholesterol antibody (ACHA) production in HAE patients and compare it with those of healthy blood donors, and to investigate the possible associations between ACHA levels and serum lipid profile alterations caused by danazol. Anti-cholesterol IgG levels were measured by ELISA and their correlation with serum concentrations of total cholesterol, HDL, LDL, triglycerides was determined in HAE patients receiving/not receiving danazol. Serum ACHA levels were significantly higher in HAE patients, compared to healthy blood donors (P < 0.0001). Longterm danazol prophylaxis had no effect on serum ACHA levels in HAE patients. However, we found a significant, negative correlation between ACHA levels and serum total cholesterol (r =−0.4033, P = 0.0200), LDL (r =−0.4565, P = 0.0076) and triglyceride (r =−0.4230, P = 0.0121) levels only in danazol-treated patients, but not in HAE patients who did not receive long-term prophylaxis. Patients with HAE have higher baseline ACHA levels compared to healthy subjects, and this might reflect polyclonal B-cell activation. The latter would be a potential explanation for the lack of an increased incidence of infectious diseases in HAE patients, but might lead to increased autoimmunity.

Hereditary angioedema: a current state-of-the-art review, V: attenuated androgens for the treatment of hereditary angioedema

OBJECTIVE

To provide a summary of the literature regarding the use of attenuated androgens during the past 40 to 50 years for the treatment of hereditary angioedema (HAE).

DATA SOURCES

MEDLINE and PubMed were searched to identify studies involving the treatment of HAE with androgens.

STUDY SELECTION

Studies were selected based on their relevance to the use of androgens for the treatment of HAE.

RESULTS

Attenuated androgens have proven successful for the short- and long-term treatment of HAE. Adverse effects are still concerning, and their use in children and pregnant women must be undertaken with great caution. Scheduled monitoring of liver function tests and lipid profiles in patients treated with these medications is critical.

CONCLUSIONS

Attenuated androgens have been successful in the short- and long-term treatment of HAE, and they are still the most frequently used medications in the United States for the treatment of this disease. There is a lack of readily available options for the treatment of acute HAE attacks apart from the administration of fresh frozen plasma or safe prophylactic therapies; however, several appropriate agents currently in clinical trials in the United States appear promising.

Hereditary angiodema: a current state-of-the-art review, VII: Canadian Hungarian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema

BACKGROUND

We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) in 2004.

OBJECTIVE

To ensure that this consensus remains current.

METHODS

In collaboration with the Canadian Network of Rare Blood Disorder Organizations, we held the second Canadian Consensus discussion with our international colleagues in Toronto, Ontario, on February 3, 2006, and reviewed its content at the Fifth C1 Inhibitor Deficiency Workshop in Budapest on June 2, 2007. Papers were presented by international investigators, and this consensus algorithm approach resulted.

RESULTS

This consensus algorithm outlines the approach recommended for the diagnosis, therapy, and management of HAE, which was agreed on by the authors of this report. This document is only a consensus algorithm approach and continues to require validation. As such, participants agreed to make this a living 2007 algorithm, a work in progress, and to review its content at future international HAE meetings.

CONCLUSIONS

There is a paucity of double-blind, placebo-controlled trials on the treatment of HAE, making levels of evidence to support the algorithm less than optimal. Controlled trials currently under way will provide further insight into the management of HAE. As with our Canadian 2003 Consensus, this 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of HAE was formed through the meeting and agreement of patient care professionals along with patient group representatives and individual patients.

Hereditary angioedema: Safety of long-term stanozolol therapy

BACKGROUND

Attenuated androgens control attacks of hereditary angioedema. Short-term studies of such patients treated at our institution with attenuated androgens demonstrated no adverse effects. However, the side-effect frequencies in patients receiving long-term treatment are relatively less well characterized.

OBJECTIVE

To assess the frequencies of various side effects of the attenuated androgen stanozolol in a population of patients with hereditary angioedema treated for 20 to 40 years.

METHODS

Data on side effects in patients who continued stanozolol therapy since 1987 were obtained by means of questionnaire. Patients were evaluated by physical examination; biochemical assays of hepatic function, serum lipids, and prostate specific antigen; and liver ultrasound.

RESULTS

The minimal initial effective dosage of stanozolol was 0.5 to 2.0 mg daily, although most patients achieved symptomatic control and decreased the dose and frequency as the frequency of attacks decreased. Treatment-related symptoms developed in 10 of 21 patients. No interruption in stanozolol therapy was required because symptoms subsided with a reduction in the stanozolol dosage. Adverse side effects included hirsutism, weight gain, menstrual irregularities or postmenopausal bleeding, acne, and mood changes. Liver enzyme assays revealed no persistent abnormalities. Liver ultrasounds in 8 patients revealed 3 abnormalities deemed unrelated to therapy. Five patients had a reduced high-density lipoprotein, and 2 patients had elevated triglycerides.

CONCLUSION

Stanozolol is a safe and effective drug for the long-term management of hereditary angioedema.

CLINICAL IMPLICATIONS

Stanozolol may be used in the long-term treatment of patients with hereditary angioedema provided such patients are closely supervised with routine clinical, biochemical, and radiologic assessments.

Management of hereditary angioedema in pediatric patients

Hereditary angioneurotic edema is a rare disorder caused by the congenital deficiency of C1 inhibitor. Recurring angioedematous paroxysms that most commonly involve the subcutis (eg, extremities, face, trunk, and genitals) or the submucosa (eg, intestines and larynx) are the hallmarks of hereditary angioneurotic edema. Edema formation is related to reduction or dysfunction of C1 inhibitor, and conventional therapy with antihistamines and corticosteroids is ineffective. Manifestations occur during the initial 2 decades of life, but even today there is a long delay between the onset of initial symptoms and the diagnosis of hereditary angioneurotic edema. Although a variety of reviews have been published during the last 3 decades on the general management of hereditary angioneurotic edema, little has been published regarding management of pediatric hereditary angioneurotic edema. Thus, we review our experience and published data to provide an approach to hereditary angioneurotic edema in childhood.

An evaluation of tests used for the diagnosis and monitoring of C1 inhibitor deficiency: normal serum C4 does not exclude hereditary angio-oedema

Reduced levels of serum C4 have been considered a ubiquitous finding in hereditary angio-oedema (HAE), and consequently low C4 is often used to 'request manage' access to C1 inhibitor assays in the United Kingdom. However, in our experience normal C4 may occasionally be compatible with HAE. We audited the results of serum C4, C1 inhibitor antigen (C1inhA) and C1 inhibitor function (C1inhF) in 49 HAE patients, compared to a control group of 58 unaffected subjects. The sensitivity of low serum C4 for HAE among untreated patients was 81%; levels of complement C4 were within the normal range on nine separate occasions in five untreated HAE patients. Molecular genetic analysis of these individuals demonstrated novel mutations in the C1 inhibitor gene. The supplied reference ranges for the Quidel C1inhF enzyme-linked immunosorbent assay (ELISA) system appear to be too low, with a sensitivity of just 57% for HAE. Following optimization of the reference ranges using receiver operating characteristic analysis, low C1inhF was found to be 78% sensitive and 100% specific for HAE. The diagnosis of HAE is not excluded by normal levels of complement C4. We conclude that C1 inhibitor studies should be performed regardless of serum C4 where a high index of clinical suspicion exists.

The deficiency of C1 inhibitor and its treatment

In this article, we review the traditional therapies of hereditary angioedema (HAE) that have been used for several years. Some of these therapies were proposed before the definition of the underlying defect and the understanding of the pathogenesis of the disease. We also describe new compounds under investigation at present as potential therapies for HAE. Two of these new therapies (a plasma-kallikrein inhibitor and a bradykinin B(2)-receptor antagonist) have been developed based on the understanding that the pathogenesis of symptoms was mainly due to kallikrein activation and bradykinin release.

C1-inhibitor concentrate home therapy for hereditary angioedema: a viable, effective treatment option

Economic and political factors have led to the increased use of home therapy programmes for patients who have traditionally been treated in hospital. Many patients with hereditary angioedema (HAE) experience intermittent severe attacks that affect their quality of life and may be life-threatening. These attacks are treated with C1-inhibitor concentrate which, for most patients, is infused at the local hospital. Home therapy programmes for HAE are currently being established. This paper reviews the extent of use of these programmes and summarizes the advantages and potential disadvantages of the concept so far.

Genetic test indications and interpretations in patients with hereditary angioedema

Patients with hereditary angioedema (HAE) present with recurrent, circumscribed, and self-limiting episodes of tissue or mucous membrane swelling caused by C1-inhibitor (CI-INH) deficiency. The estimated frequency of HAE is 1:50,000 persons. Distinguishing HAE from acquired angioedema (AAE) facilitates therapeutic interventions and family planning or testing. Patients with HAE benefit from treatment with attenuated androgen, antifibrinolytic agents, and C1-INH concentrate replacement during acute attacks. HAE is currently recognized as a genetic disorder with autosomal dominant transmission. Other forms of inherited angioedema that are not associated with genetic mutations have also been identified. Readily available tests are complement studies, including C4 and C1-esterase inhibitor, both antigenic and functional C1-INH. These are the most commonly used tests in the diagnosis of HAE. Analysis of C1q can help differentiate between HAE and AAE caused by C1-INH deficiency. Genetic tests would be particularly helpful in patients with no family history of angioedema, which occurs in about half of affected patients, and in patients whose C1q level is borderline and does not differentiate between HAE and AAE. Measuring autoantibodies against C1-INH also would be helpful, but the test is available in research laboratories only. Simple complement determinations are appropriate for screening and diagnosis of the disorder.

Hereditary angioedema

PURPOSE OF REVIEW

Hereditary angioedema is an autosomal-dominant deficiency of C1 inhibitor--a serpin inhibitor of kallikrein, C1r, C1s, factor XII, and plasmin. Quantitative or qualitative deficiency of C1 inhibitor leads to the generation of vasoactive mediators, most likely bradykinin. The clinical syndrome is repeated bouts of nonpruritic, nonpitting edema of the face, larynx, extermities, and intestinal viscera. Recently, investigators, physicians, and industry have demonstrated a renewed interest in the biology and treatment of hereditary angioedema.

RECENT FINDINGS

Investigators have generated a C1INH-/- mouse model that has demonstrated the importance of the contact activation system for hereditary angioedema-related vascular permeability. An interactive database of mutations is available electronically. Investigators have continued exploration into mRNA/protein levels. The proceedings of a recent workshop have been impressive in the scope and depth. Clinicians have produced consensus documents and expert reviews. The pharmaceutical industry has initiated clinical trails with novel agents.

SUMMARY

Hereditary angioedema is often misdiagnosed and poorly treated. Diagnosis requires careful medical and family history and the measurement of functional C1 inhibitor and C4 levels. Attenuated androgens, anti-fibrinolytics, and C1 inhibitor concentrates are used for long-term and preprocedure prophylaxis, but have significant drawbacks. C1 inhibitor concentrates and fresh frozen plasma are available for acute intervention. The mainstays of supportive care are airway monitoring, pain relief, hydration, and control of nausea. New agents such as recombinant C1 inhibitor, kallikrein inhibitors, and bradykinin inhibitors may offer safer and more tolerable treatments.

C1 inhibitor deficiency: consensus document

We present a consensus document on the diagnosis and management of C1 inhibitor deficiency, a syndrome characterized clinically by recurrent episodes of angio-oedema. In hereditary angio-oedema, a rare autosomal dominant condition, C1 inhibitor function is reduced due to impaired transcription or production of non-functional protein. The diagnosis is confirmed by the presence of a low serum C4 and absent or greatly reduced C1 inhibitor level or function. The condition can cause fatal laryngeal oedema and features indistinguishable from gastrointestinal tract obstruction. Attacks can be precipitated by trauma, infection and other stimulants. Treatment is graded according to response and the clinical site of swelling. Acute treatment for severe attack is by infusion of C1 inhibitor concentrate and for minor attack attenuated androgens and/or tranexamic acid. Prophylactic treatment is by attenuated androgens and/or tranexamic acid. There are a number of new products in trial, including genetically engineered C1 esterase inhibitor, kallikrein inhibitor and bradykinin B2 receptor antagonist. Individual sections provide special advice with respect to diagnosis, management (prophylaxis and emergency care), special situations (childhood, pregnancy, contraception, travel and dental care) and service specification.

Hereditary angioedema presenting as epiglottitis

Hereditary angioedema is a disorder characterized by decreased levels or function of complement C1 esterase inhibitor. Symptoms in children generally consist of recurrent episodes of soft tissue swelling. On rare occasion, it can cause airway edema which may lead to airway obstruction. A case is presented of a child presenting with epiglottitis requiring intubation. Initial management of this rare complication should be directed at establishing an adequate airway and ensuring good oxygenation and ventilation. In addition, prompt administration of C1 esterase inhibitor concentrate is the most effective means of stopping progression of laryngeal edema and other forms of swelling. Commonly used agents for airway edema such as glucocorticoids, antihistamines, H1-blockers, and epinephrine tend not to be effective for reducing swelling related to hereditary angioedema.

How do we treat patients with hereditary angioedema

Hereditary angioedema (HAE) is due to the inherited deficiency of C1-Inhibitor (C1-Inh). When specific treatment was not available, the mortality rate for this disease was as high as 50% and the disability up to 100-150 days per year (Agostoni and Cicardi, Hereditary and acquired C1-inhibitor deficiency: biological and clinical characteristics in 235 patients). Such a worrying scenario dramatically improves upon appropriate treatment. Nevertheless, the disease still frequently goes undiagnosed or misdiagnosed as an allergic condition. Both circumstances prevent patients from receiving drugs that could save and/or improve the quality of their life. The interest of our group for patients with HAE goes back to the early seventies. Since that time, 441 such patients have been examined and treated at our department; 403 are still actively followed. Here we present our experience on the treatment of HAE.

Increased expression of C1-inhibitor mRNA in patients with hereditary angioedema treated with Danazol

The attenuated androgen Danazol can partially reverse the biochemical defect and prevent angioedema in patients with inherited C1-inhibitor (C1-INH) deficiency (hereditary angioedema, HAE). Though its clinical effectiveness is independent from significant increase of C1-INH plasma levels, its mechanism of action remains unknown. Since angioedema is a local phenomenon, it could be controlled by restoring tissue levels of C1-INH. We measured the expression of C1-INH mRNA in peripheral blood mononuclear cells (PBMCs) of 13 patients with HAE type 1 (seven untreated and asymptomatic, and six on Danazol at the minimal effective dose) and of eight normal controls. mRNA levels were quantitated by computerized optical densitometry of reverse transcriptase-PCR products, normalized for the amount of glyceraldehyde-3-phosphate-dehydrogenase and expressed as percent of normal pooled RNAs. Each determination represented the mean of three separate experiments. Measurement of C1-INH mRNA in two patients before and after 1 month of Danazol 400 mg per day demonstrated a post-treatment increase of 15 and 21%, respectively. When HAE patients and controls were analyzed as groups, C1-INH mRNA levels of patients untreated and asymptomatic (median 73%, range 65-78) were significantly lower (P=0.001) compared to controls (median 101%, range 87-121) and to patients on Danazol (median 91%, range 82-96); the difference among the last two groups was not statistically significant. Our data demonstrate that minimal effective doses of Danazol increase the expression of C1-INH mRNA in PBMC of HAE patients even in the absence of a significant increase of C1-INH plasma levels.

Pharmacotherapy of premenstrual syndromes and premenstrual dysphoric disorder: current practices

Premenstrual syndromes (PMS) and especially premenstrual dysphoic disorder (PMDD) affect a large segment of the population of women of reproductive age. Treatment is necessary in approximately 2-10% of women with PMS and PMDD because of the degree of impairment and distress experienced. Treatment modalities are increasingly based on hypotheses concerning possible underlying biological mechanisms: mostly ovulation-related hormonal changes and serotonergic abnormalities. Two treatment modalities distinguish themselves as highly effective: suppression of ovulation and specific serotonin re-uptake inhibitor (SSRI) antidepressants. Suppression of ovulation is effective for a wide range of PMS, while SSRIs are effective for PMDD with some degree of efficacy for physical symptoms. The SSRIs are also efficacious when administered intermittently--only during the luteal phase of the menstrual cycle.

Clinical management of hereditary angio-oedema in children

Hereditary angio-oedema (HAE) results from the deficiency of C1-esterase inhibitor (C1-INH). The clinical picture of this autosomal dominant disorder is characterized by recurrent attacks of subcutaneous oedema and/or potentially life-threatening swelling of the submucosa. This review discusses the authors' decade-long experience obtained in the treatment and follow-up of pediatric patients with HAE. Twenty-six children with HAE were reviewed. Pedigree analysis was performed in all cases to identify afflicted relatives. C1-INH concentrate was reserved for the emergency treatment of acute oedematous attacks, whereas tranexamic acid and danazol were administered for short- or long-term prophylaxis. Follow-up care included laboratory tests and abdominal ultrasound, which was repeated at regular intervals. Twenty-one children had Type I HAE and five suffered from Type II HAE. Clinical manifestations of the disease first occured in children when 2.5-12 years of age. Oedema formation primarily afflicted subcutaneous tissues. Mechanical trauma was identified as a precipitating factor in 20 patients. Pedigree analysis revealed 24 patients with relatives who suffered from HAE. Long-term prophylaxis with tranexamic acid or danazol was initiated in 11 patients; two children required short-term prophylaxis. No drug-related adverse effects were observed, except for one case of delayed menarche. Therapy improved serum complement parameters significantly and substantially reduced the frequency and severity of clinical episodes. Adequate prophylaxis and follow-up care can spare pediatric patients from oedematous attacks caused by HAE. Undesirable adverse effects can be avoided and the patient's quality of life enhanced considerably by administering the lowest effective drug dose.

Current management of hereditary angio-oedema (C'1 esterase inhibitor deficiency)

Hereditary angio-oedema is characterised by recurrent swellings in any part of the body and also by recurrent attacks of severe abdominal pain. The disease is inherited in an autosomal dominant manner but up to 25% of cases can occur as a spontaneous mutation. Attacks of swelling can be precipitated by trauma, certain drugs, and emotional stress. Treatment usually involves a combination of prophylaxis, using androgens or antifibrolytic drugs, and replacement with C'1 esterase inhibitor concentrate for acute attacks and before surgery or other traumatic procedures.

Complement component 1 inhibitor (C1-INH) like protein on murine spermatozoa: anti-C1-INH inhibits in vitro fertilization

We investigated if complement component 1 inhibitor-like (C1-INH-L) protein found on human spermatozoa exists on mouse spermatozoa and is relevant to reproduction. We used Western blot analysis and immunofluorescence assays to detect C1-INH on murine sperm and tested the effects of the antibodies to C1-INH and albumin (negative control) on in vitro mouse sperm motility and fertilization. C1-INH-L, with molecular weight similar to human C1-INH (100 kDa), was present on the surface of spermatozoan head and midpiece. Treating mouse sperm with anti-C1-INH reduced the mouse sperm motility (P < 0.01), in vitro fertilization (P < 0.01) and embryo development rates (P < 0.01). Anti-albumin failed to do so. We conclude that C1-inhibitor-like protein is present on mouse sperm surface and appears to be relevant to reproduction.

The presence of a C1-inhibitor-like molecule (C1-INH-L) on human sperm: its involvement in sperm motility

PROBLEM

An 88-92-kDa C1-inhibitor-like molecule (C1-INH-L) was previously identified to elicit cytotoxic sperm antibody response in infertile men and women. Here, we document that it is present on the human sperm surface and could be detected by an enzyme-labeled immunoglobulin G (IgG) fraction of anti-human C1-INH antibody.

METHOD OF STUDY

Western blot analysis, enzyme-lined immunoadsorbent assay (ELISA) and computerized sperm motion analysis.

RESULTS

The existence of C1-INH-L on the sperm surface is calcium independent. Phosphatidylinositol-specific phospholipase C (PIPLC), EDTA, and acid (pH 3.0) could not remove the C1-INH-L from sperm, but trypsin did. Activated C1s was able to bind to the sperm surface. Immunofluorescence studies localized the protein to the head and midpiece of the sperm membrane. The C1-INH-L exists on both uncapacitated and capacitated sperm surfaces, which suggests that this protein is a sperm-surface protein. The heat-treated (56 degrees C, 30 min) IgG fraction of anti-C1-INH greatly reduced the percentage of motile spermatozoa and the progressive and path velocities in the absence of complement.

CONCLUSION

Our data suggest that C1-INH is a sperm membrane-anchored protein that may have complement and sperm motility regulatory function.

Efficacy of danazol in a patient with congenital protein-S deficiency: paradoxical evidence for decreased platelet activation with increased thrombin generation

Danazol, a synthetic attenuated anabolic steroid, has been administered for 36 months to a 32 year old male with hereditary Protein S (PS) deficiency who had become non-compliant for warfarin therapy. The patient has an eleven year history of venous thrombosis. Since danazol therapy was initiated, the patient has not experienced a thrombotic event or adverse side-effects. Levels of PS, other inhibitors, fibrinolytic components, and markers for thrombin and platelet activation were measured prior and subsequent to therapy. Following danazol administration, marked and sustained increases were noted in Free Protein S, Antithrombin, and Protein C. Platelet CD62 (P-selectin) positivity which was elevated before therapy, decreased to assay threshold limits within five weeks. Both Prothrombin Fragment 1.2 and thrombin-antithrombin complexes were elevated post danazol therapy indicating continued clearance of generated thrombin. These data suggest that the protective effect provided by danazol in this patient with hereditary PS deficiency, may in large part be due to suppression of platelet activation by thrombin inhibition than simply through elevation of PS.

Long-term treatment of hereditary angioedema with attenuated androgens: a survey of a 13-year experience

Fifty-six patients affected with hereditary angioedema have been followed during long-term prophylaxis with attenuated androgens. The treatment was started in patients who had one or more severe attacks per month. In 24 patients, the therapy lasted for more than 5 years. The minimal effective dose usually did not exceed 2 mg/day of stanozolol or 200 mg/day of danazol. Only in two patients were these doses not sufficient to achieve the complete disappearance of symptoms. Irregular menstruation, but rarely amenorrhea, was the only significant side effect. One patient had to stop the therapy because of laboratory signs of hepatic cell necrosis. In one patient, danazol was administered during the last 8 weeks of pregnancy without side effects for the mother but with transient signs of virilization for the female baby. To find a biochemical marker for the minimal effective dose of androgen derivatives, we measured the plasma levels of C1 C1 INH complexes at different doses of stanozolol in four patients with hereditary angioedema. We found that these complexes, elevated before treatment, promptly reverted to normal values during androgen therapy and remained normal with any reduction of the dose of the drug as long as the patient remained symptom free. Therefore, the measurement of C1 C1 INH complexes appears to reflect the activity of the disease and not the amount of androgen that is administered.

Hereditary angioedema: its diagnostic and management perspectives

Although hereditary angioedema accounts for only a small fraction of all cases of angioedema, it is the most common genetically linked clinical disorder caused by the deficiency of a protein associated with complement activation. Attacks may be complicated by incapacitating cutaneous swelling, life-threatening upper airway impediment, and severe gastrointestinal colic. Recent physicochemical and genetic studies have contributed significantly to our understanding of the structure of the inhibitor protein. Measurement of serum C4 titer is an efficacious screening test. Normal levels during symptomatic periods rule out the diagnosis, whereas decreased levels warrant determination of C1 esterase inhibitor titer by immunoassay or functional assay. The functional assay is necessary to ascertain the genetic variant form. The importance of making the correct diagnosis cannot be overemphasized. It can avert potentially fatal consequences, such as upper airway obstruction and unnecessary abdominal surgery. The application of short-term preventive measures can avoid complications associated with trauma. Finally, abatement or elimination of symptoms in patients with incessant and disabling attacks can be attained by long-term therapy with currently available attenuated androgens.

Angioedema with acquired deficiency of the C1 inhibitor: a constellation of syndromes

Patients with angioedema are often referred to an allergist to rule out an allergic cause. In most of these cases, no allergic cause is identified, and the cases are labeled "idiopathic." Occasionally, a deficiency of the inhibitor of the first component of complement (C1INH) is discovered, which may be either hereditary or acquired. In comparison with the hereditary variant, the acquired deficiency of C1INH is extremely rare, approximately 40 cases having been reported to date. Measurement of the C1q subunit is the key to the differential diagnosis between hereditary and acquired deficiencies of C1INH--it is normal in the former and decreased in the latter. The acquired deficiency of C1INH is usually found in association with benign or malignant B-cell lymphoproliferative disorders, and the angioedema responds to therapy with androgens. A subset of six patients with acquired C1INH deficiency has been reported recently; they had anti-C1INH autoantibodies, no evidence of an underlying disease, a benign course, and variable responses to therapy. Two new cases of angioedema in patients with acquired C1INH deficiency are described in this report. One patient had no evidence of an underlying disease 11 years after the onset of angioedema. The other case was associated with a B-cell lymphoproliferative disorder that became evident 9 months after C1INH deficiency was diagnosed, and androgen therapy stopped the attacks of angioedema. In this second case, the functional activity of C1INH mirrored the clinical response to therapy.

[Drugs inhibiting complement activation]

Complement may be activated by anaesthetic agents as well as contrast media, and so could anaphylactoid reactions be induced. Efficient and harmless complement blocking agents were still lacking. The only agents actually used by anaesthetists were steroids and/or antifibrinolytic drugs. Other agents were not indicated in surgical patients because of their adverse effects and the impossibility of giving them by the intravenous route.