Pediatric hereditary angioedema: an update

Clinical profile and management of pediatric hereditary angioedema in resource-constrained settings: our experience from a single centre in North India

Hereditary angioedema (HAE) is a rare genetic disorder. The pattern of HAE is different in children as compared to adults. There is limited literature from developing countries where all first-line treatments are either unavailable or not easily accessible. Data of children with HAE were retrieved from medical records of patients registered in the Pediatric Immunodeficiency Clinic at our institute. Of the 206 patients with HAE, 61 were diagnosed before the age of 18 years. Male: female ratio was 1.1:1. Median age at onset of symptoms and diagnosis were 6.2 years (range 1-17 years) and 10.7 years (range 1.5-18 years) respectively. Median delay in diagnosis was 4.9 years (range 0-16 years). The commonest presentation was facial swelling (51/61) followed by swelling of extremities (47/61). Laryngeal edema and abdominal symptoms were reported in 28/61 and 31/61 patients respectively. Abdominal attacks were found to be less common in children as compared to adults. Most patients in our cohort received fresh-frozen plasma (n = 5/61) as on-demand therapy. Long-term prophylaxis included attenuated androgens (n = 25/61) and tranexamic acid (n = 23/61). Median duration of follow-up was 2242 patient months. One patient died on follow-up in this cohort. This is the largest single-centre cohort of pediatric HAE from resource-constrained settings. Facial attacks were more common, and there were significant delays in diagnosis when the age of onset of symptoms was younger. Gastrointestinal symptoms were less common in children than adults. HIGHLIGHTS: One of the largest single-centre cohorts of pediatric HAE and the only one from resource-constrained settings. There were significant delays in diagnosis when the age of onset of symptoms was younger. Abdominal attacks were found to be less common in children as compared to adults.

Myeloid lineage cells evince distinct steady-state level of certain gene groups in dependence on hereditary angioedema severity

Hereditary angioedema (HAE) is a rare genetic disorder with variable expressivity even in carriers of the same underlying genetic defect, suggesting other genetic and epigenetic factors participate in modifying HAE severity. Recent knowledge indicates the role of immune cells in several aspects of HAE pathogenesis, which makes monocytes and macrophages candidates to mediate these effects. Here we combined a search for HAE phenotype modifying gene variants with the characterization of selected genes' mRNA levels in monocyte and macrophages in a symptom-free period. While no such gene variant was found to be associated with a more severe or milder disease, patients revealed a higher number of dysregulated genes and their expression profile was significantly altered, which was typically manifested by changes in individual gene expression or by strengthened or weakened relations in mutually co-expressed gene groups, depending on HAE severity. SERPING1 showed decreased expression in HAE-C1INH patients, but this effect was significant only in patients carrying mutations supposedly activating nonsense-mediated decay. Pro-inflammatory CXC chemokine superfamily members CXCL8, 10 and 11 were downregulated, while other genes such as FCGR1A, or long non-coding RNA NEAT1 were upregulated in patients. Co-expression within some gene groups (such as an NF-kappaB function related group) was strengthened in patients with a severe and/or mild course compared to controls. All these findings show that transcript levels in myeloid cells achieve different activation or depression levels in HAE-C1INH patients than in healthy controls and/or based on disease severity and could participate in determining the HAE phenotype.

Short-term prophylaxis for children and adolescents with hereditary angioedema

Background: Hereditary Angioedema (HAE) is a rare, autosomal dominant, life threatening disease, secondary to the deficiency of C1-inhibitor, dysfunction of C1-inhibitor or inadequate control of the contact pathway. Presentation includes recurrent swelling of the skin, upper airway and the abdomen. Trauma can precipitate attacks, which in the airway can lead to asphyxia. For this reason, short term prophylaxis (STP) may be indicated before medical, surgical and dental procedures. The goal of the manuscript is to review short term prophylaxis for children of all ages. Methods: We searched the following search words: children, pediatric, adolescent, plasma derived C1-inhibitor, recombinant C1-inhibitor, surgery, medical procedures, prophylaxis, dental, Hereditary Angioedema, tranexamic acid, androgens, fresh frozen plasma, short term prophylaxis, lanadelumab, subcutaneous C1-inhibitor in Google Scholar and in PubMed to develop our results. Results: STP should be discussed at every visit. Plans should be individualized based upon the procedure, therapies available and shared decision making with patient/parent. For high risk procedures plasma derived C1-inhibitor should be used at 20 units/kg just prior to the procedure. Alternative agents for STP include recombinant C1-inhibitor, fresh frozen plasma, androgens, or tranexamic acid. In all cases, with or without the use of STP, 2 doses of on-demand therapy should be available in case of an attack. Conclusion: Herein, we review the published data on STP for pediatric patients with HAE and discuss first-line options, and off label use of medications, as well as review the guidelines pertaining to short term prophylaxis.

Pediatric hereditary angioedema: what the otolaryngologist should know

PURPOSE OF REVIEW

To review pediatric hereditary angioedema for otolaryngologists, with emphasis on articles within the past 12-18 months.

RECENT FINDINGS

Biologic therapies are accepted for adult hereditary angioedema (HAE), but have been studied less for pediatric HAE. Recent literature supports expanded use of biologic agents in pediatrics as acute treatment and prophylaxis. Available agents include plasma-derived C1 esterase inhibitors (C1-INH) (Berinert, Haegarda, Cinryze), recombinant C1-INH (Ruconest), bradykinin B2 receptor inhibitor (Icatibant), and kallikrein inhibitors (Ecallantide and lanadelumab). Of these, only Berinert is Food and Drug Administration (FDA) approved for acute therapy for children under 12 years of age. Ruconest is approved for treatment of acute attacks over age 13. Ecallantide also has FDA approval as acute treatment for age 12 and older, while lanadelumab and Haegarda are prophylactic agents for adolescents. Icatibant lacks FDA approval in patients under 18 years of age. Cinryze has FDA approval only for prophylaxis for children as young as 6 years old.

SUMMARY

Pediatric HAE is a potentially life-threatening disease. Targeted biologic agents have gained acceptance in treatment of acute attacks, and their use as prophylactic agents is changing the focus of management from acute intervention to preventive management. While intubation or surgical airway management may still be necessary, early intervention or prophylaxis can decrease morbidity and improve quality of life.

Oral plasma kallikrein inhibitor BCX7353 for treatment of hereditary angioedema

Hereditary angioedema (HAE) is rare disorder caused by a SERPING1 gene mutation that triggers severe swelling of the skin and upper airway. Treatment options for HAE with deficient and dysfunctional C1-inhibitor are expanding to include small-molecule drugs that inhibit protein interactions in the kallikrein-kinin system. Discovered by BioCryst Pharmaceuticals, BCX7353 is a synthetic, once-daily, small molecule drug that can be taken as an oral capsule to treat HAE attacks and for prophylaxis. This article will summarize recent and current BCX7353 clinical trials. Overall, results indicate BCX7353 is a promising form of therapy with a rapid 1 h onset of action, long duration of action, and acceptable tolerance.