Acquired Angioedema due to C1-Inhibitor Deficiency: A Challenging Condition.

BACKGROUND: Acquired deficiency of C1 inhibitor (AAE-C1-INH) is a very rare cause of recurrent angioedema, with few cases reported in the literature. We aimed to describe a series of patients with AAE-C1-INH who were diagnosed and received care at angioedema reference centers in Brazil, affiliated to the Brazilian Group of Studies on Hereditary Angioedema. METHODS: Fourteen patients from 8 Brazilian Angioedema Reference Centers, diagnosed with AAE-C1-INH, were included in this study. Clinical data collected included sex, date of birth, date of onset of symptoms, date of diagnosis, plasma levels of antigenic and/or functional C1-INH, levels of C4 and C1q, location and treatment of angioedema attacks, long-term prophylaxis, associated diseases, and definitive treatment. RESULTS: Fourteen patients were identified with AAE-C1-INH. Most patients (10/14; 71.4%) were female. The median age at onset of symptoms was 56.5 years (range, 14-74 years; interquartile range [IQR], 32-64 years), and median age at diagnosis was 58.0 years (range, 20-76 years; IQR, 38-65 years), with a median time until diagnosis of 2 years (range, 0-6 years; IQR, 1-3 years). The most common manifestations were cutaneous (face, eyelids, lips, trunk, hands, feet, and genitals). Most patient had low levels of C4 (13/14; 92.8%) and of antigenic C1-INH (8/14; 57.1%). Four had decreased functional activity of C1-INH (4/7; 57.1%) and C1q levels were low in 5 patients (5/12; 41.6%). Underlying diseases were identified in all 14 patients, with lymphoma of the splenic marginal zone and monoclonal gammopathy of undetermined significance being the most frequent. Nine patients (64.2%) needed long-term prophylactic treatment for recurrent angioedema and 5 patients (46.7%) required treatment for angioedema attacks. Most of them (12/14; 85.7%) had resolution of angioedema. CONCLUSION: Therapy of AAE-C1-INH aims to control symptoms; however, diagnosis and treatment of the underlying disease, when present, should be an important target and may lead to the resolution of angioedema in patients with AAE-C1-INH.

Hereditary angioedema in children and adolescents.

Hereditary angioedema is a genetic disease with autosomal dominant inheritance and, in most cases, caused by C1 inhibitor deficiency. Patients present with recurrent edema affecting sub-cutaneous and mucus membranes with variable onset and severity. More than 50% of patients may become symptomatic before 10 years of age. Family history can help with the diagnosis; however, approximately 25% of the cases are de novo mutations. Biochemical diagnosis should be delayed until after 1 year of age. Children were often excluded from advances in therapy for hereditary angioedema since most of the new medicines were tested in adults and thus excluded by the Food and Drug Administration (FDA) and other agencies for approval to be used in children. Treatment of attacks is available for the pediatric patient; however, barriers still exist for the use of long-term prophylaxis in young children. © 2022 Codon Publications. Published by Codon Publications.

Outcome of SARS-CoV-2 Infection in 121 Patients with Inborn Errors of Immunity: A Cross-Sectional Study.

PURPOSE: There is still scarce data on SARS-CoV-2 infection in patients with Inborn Errors of Immunity (IEI) and many unresolved questions. We aimed to describe the clinical outcome of SARS-CoV-2 infection in Brazilian IEI patients and identify factors influencing the infection. METHODS: We did a cross-sectional, multicenter study that included patients of any age affected by IEI and SARS-CoV-2 infection. The variables studied were sex, age, type of IEI, comorbidities (number and type), treatment in use for IEI, clinical manifestations and severity of SARS-CoV-2 infection. RESULTS: 121 patients were included: 55.4% female, ages from six months to 74 yo (median age = 25.1 yo). Most patients had predominantly antibody deficiency (n = 53). The infection was mostly asymptomatic (n = 21) and mild (n = 66), and one child had multisystem inflammatory syndrome (MIS-C). We could not observe sex-related susceptibility, and there was a weak correlation between age and severity of infection. The number of comorbidities was higher in severe cases, particularly bronchiectasis and cardiopathy. There were no severe cases in hereditary angioedema patients. Six patients aged 2 to 74 years died, three of them with antibody deficiency. CONCLUSION: The outcome was mild in most patients, but the Case Fatality Ratio was higher than in the general population. However, the type of IEI was not a determining factor for severity, except for complement deficiencies linked to milder COVID-19. The severity of SARS-CoV-2 infection seems to be more related to older age, a higher number of comorbidities and type of comorbidities (bronchiectasis and cardiopathy).

The Challenges in the Follow-Up and Treatment of Brazilian Children with Hereditary Angioedema.

INTRODUCTION: Hereditary angioedema (HAE) with C1 inhibitor (C1-INH) deficiency is a rare autosomal dominant disease. Although the first symptoms can appear in childhood, the diagnosis's delay has a strong impact on the patient's quality of life. We analyzed clinical and laboratory characteristics and the drug therapy of pediatric patients with HAE in Brazil. METHODS: Medical records from 18 reference centers of HAE patients under 18 years of age were evaluated after confirmed diagnosis was performed by quantitative and/or functional C1-INH. RESULTS: A total of 95 participants (51 M:44 F; mean age: 7 years old) out of 17 centers were included; 15 asymptomatic cases were identified through family history and genetic screening. Angioedema attacks affected the extremities (73.5%), gastrointestinal tract (57%), face (50%), lips (42.5%), eyelids (23.7%), genitals (23.7%), upper airways (10%), and tongue (6.3%). Family history was present in 84% of patients, and the mean delay in the diagnosis was 3.9 years. Long-term prophylaxis (51/80) was performed with tranexamic acid (39/80) and androgens (13/80); and short-term prophylaxis (9/80) was performed with tranexamic acid (6/80) and danazol (3/80). On-demand therapy (35/80) was prescribed: icatibant in 7/35, fresh frozen plasma in 16/35, C1-INH plasma-derived in 11/35, and tranexamic acid in 12/35 patients. CONCLUSIONS: This is the first study on HAE pediatric patients in Latin America. Clinical manifestations were similar to adults. Drugs such as androgens and tranexamic acid were indicated off-label, probably due to restricted access to specific drugs. Educational programs should address pediatricians to reduce late diagnosis and tailored child therapy.

New mutations in SERPING1 gene of Brazilian patients with hereditary angioedema.

Hereditary Angioedema is an autosomal dominant inherited disease leading to oedema attacks with variable severity and localization predominantly caused by C1-INH deficit. More than 400 mutations have been already identified, however no genetic analysis of a Brazilian cohort of HAE patients with C1-INH deficiency has been published. Our aim was to perform genetic analysis of C1-INH gene (SERPING1) in Brazilian HAE patients. We screened the whole SERPING1 coding region from 30 subjects out of 16 unrelated families with confirmed diagnosis of HAE due to C1-INH deficiency. Clinical diagnosis was based on symptoms and quantitative and/or functional analysis of C1-INH. We identified fifteen different mutations among which eight were not previously described according to databases. We found five small deletions (c.97_115del19; c.553delG; c.776_782del7; c.1075_1089del15 and c.1353_1354delGA), producing frameshifts leading to premature stop codons; seven missense mutations (c.498C>A; c.550G>C; c.752T>C; c.889G>A; c.1376C>A; c.1396C>T; c.1431C>A); one nonsense mutation (c.1480C>T), and two intronic alterations (c.51+1G>T; c.51+2T>C). Despite the small number of participants in this study, our results show mutations not previously identified in SERPING1 gene. This study represents the first Brazilian HAE cohort evaluated for mutations and it introduces the possibility to perform genetic analysis in case of need for differential diagnosis.

Genetic analysis of hereditary angioedema in a Brazilian family by targeted next generation sequencing.

Hereditary angioedema (HAE) is accompanied by an overproduction of bradykinin (BK) as the primary mediator of swelling. Although many proteins may be involved in regulating the wide spectrum of HAE symptoms, most studies have only focused on C1-INH and FXII. For the first time, a next generation sequencing (NGS) method was applied to develop a robust, time- and cost-effective diagnostic and research tool to analyze selected genes related to HAE. The entire coding region and the exon-intron boundaries of 15 genes from 23 subjects of a Brazilian family, nine of whom were symptomatic, were analyzed by NGS. One new mutation found uniquely in the nine symptomatic patients, p.Ala457Pro in the SERPING1 gene, was estimated as likely to be pathogenic (PolyPhen-2 software analysis) and is the main candidate to be responsible for HAE in these patients. Alterations identified in a few asymptomatic individuals but also found in almost all symptomatic patients, such as p.Ile197Met (HMWK), p.Glu298Asp (NOS3) and p.Gly354Glu (B2R), may also be involved in modulating patient-specific symptoms. This NGS gene panel has proven to be a valuable tool for a quick and accurate molecular diagnosis of HAE and efficient to indicate modulators of HAE symptoms.

First report of the Hyper-IgM syndrome Registry of the Latin American Society for Immunodeficiencies: novel mutations, unique infections, and outcomes.

Hyper-IgM (HIGM) syndrome is a heterogeneous group of disorders characterized by normal or elevated serum IgM levels associated with absent or decreased IgG, IgA and IgE. Here we summarize data from the HIGM syndrome Registry of the Latin American Society for Immunodeficiencies (LASID). Of the 58 patients from 51 families reported to the registry with the clinical phenotype of HIGM syndrome, molecular defects were identified in 37 patients thus far. We retrospectively analyzed the clinical, immunological and molecular data from these 37 patients. CD40 ligand (CD40L) deficiency was found in 35 patients from 25 families and activation-induced cytidine deaminase (AID) deficiency in 2 unrelated patients. Five previously unreported mutations were identified in the CD40L gene (CD40LG). Respiratory tract infections, mainly pneumonia, were the most frequent clinical manifestation. Previously undescribed fungal and opportunistic infections were observed in CD40L-deficient patients but not in the two patients with AID deficiency. These include the first cases of pneumonia caused by Mycoplasma pneumoniae, Serratia marcescens or Aspergillus sp. and diarrhea caused by Microsporidium sp. or Isospora belli. Except for four CD40L-deficient patients who died from complications of presumptive central nervous system infections or sepsis, all patients reported in this study are alive. Four CD40L-deficient patients underwent successful bone marrow transplantation. This report characterizes the clinical and genetic spectrum of HIGM syndrome in Latin America and expands the understanding of the genotype and phenotype of this syndrome in tropical areas.

Angiopoietin2 is associated with coagulation activation and tissue factor expression in extracellular vesicles in COVID-19.

Coagulation activation in immunothrombosis involves various pathways distinct from classical hemostasis, offering potential therapeutic targets to control inflammation-induced hypercoagulability while potentially sparing hemostasis. The Angiopoietin/Tie2 pathway, previously linked to embryonic angiogenesis and sepsis-related endothelial barrier regulation, was recently associated with coagulation activation in sepsis and COVID-19. This study explores the connection between key mediators of the Angiopoietin/Tie2 pathway and coagulation activation. The study included COVID-19 patients with hypoxia and healthy controls. Blood samples were processed to obtain platelet-free plasma, and frozen until analysis. Extracellular vesicles (EVs) in plasma were characterized and quantified using flow cytometry, and their tissue factor (TF) procoagulant activity was measured using a kinetic chromogenic method. Several markers of hemostasis were assessed. Levels of ANGPT1, ANGPT2, and soluble Tie2 correlated with markers of coagulation and platelet activation. EVs from platelets and endothelial cells were increased in COVID-19 patients, and a significant increase in TF+ EVs derived from endothelial cells was observed. In addition, ANGPT2 levels were associated with TF expression and activity in EVs. In conclusion, we provide further evidence for the involvement of the Angiopoietin/Tie2 pathway in the coagulopathy of COVID-19 mediated in part by release of EVs as a potential source of TF activity.

Association of Ang/Tie2 pathway mediators with endothelial barrier integrity and disease severity in COVID-19.

Endothelial barrier (EB) disruption contributes to acute lung injury in COVID-19, and levels of both VEGF-A and Ang-2, which are mediators of EB integrity, have been associated with COVID-19 severity. Here we explored the participation of additional mediators of barrier integrity in this process, as well as the potential of serum from COVID-19 patients to induce EB disruption in cell monolayers. In a cohort from a clinical trial consisting of thirty patients with COVID-19 that required hospital admission due to hypoxia we demonstrate that i) levels of soluble Tie2 were increase, and of soluble VE-cadherin were decreased when compared to healthy individuals; ii) sera from these patients induce barrier disruption in monolayers of endothelial cells; and iii) that the magnitude of this effect is proportional to disease severity and to circulating levels of VEGF-A and Ang-2. Our study confirms and extends previous findings on the pathogenesis of acute lung injury in COVID-19, reinforcing the concept that EB is a relevant component of this disease. Our results pave the way for future studies that can refine our understanding of the pathogenesis of acute lung injury in viral respiratory disorders, and contribute to the identification of new biomarkers and therapeutic targets for these conditions.

Association of heme-oxygenase 1, hemopexin, and heme levels with markers of disease severity in COVID-19.

Heme-oxygenase 1 (HO-1) is an enzyme with well-known anti-inflammatory and antioxidant properties, whose levels have been previously associated with disease severity in the context of sterile and infectious diseases. Moreover, the heme/HO-1 pathway has been associated with prothrombotic changes in other diseases. Accordingly, the potential of modulating HO-1 levels for the treatment of COVID-19 was extensively speculated during the COVID-19 pandemic, but very few actual data were generated. The aim of our study was to explore the association of HO-1, heme, and hemopexin (HPX) levels with COVID-19 severity and with markers of inflammation and coagulation activation. The study was conducted in 30 consecutive patients with COVID-19 admitted due to hypoxemia, and 30 healthy volunteers matched by sex, age, and geographic region. HO-1 and HPX levels were measured by enzyme immunoassay (ELISA) and heme levels were measured by a colorimetric method. A comprehensive panel of coagulation and fibrinolysis activation was also used. Patients with COVID-19 presented increased levels of HO-1 when compared to controls (5741 ± 2696 vs 1953 ± 612 pg/mL, respectively, P < 0.0001), as well as a trend toward increased levels of HPX (3.724 ± 0.880 vs 3.254 ± 1.022 mg/mL, respectively; P = 0.06). In addition, HO-1 and HPX levels reduced from admission to day + 4. HO-1 levels were associated with duration of intensive care unit stay and with several markers of coagulation activation. In conclusion, modulation of HO-1 could be associated with the prothrombotic state observed in COVID-19, and HO-1 could also represent a relevant biomarker for COVID-19. New independent studies are warranted to explore and expand these findings.

Podoplanin and CLEC-2 levels in patients with COVID-19.

Introduction: Podoplanin (PDPN gene) and CLEC-2 are involved in inflammatory hemostasis and have also been related with the pathogenesis of thrombosis. Emerging evidence also suggest that podoplanin can exert protective effects in sepsis and in acute lung injury. In lungs, podoplanin is co-expressed with ACE2, which is the main entry receptor for SARS-CoV-2. Aim: To explore the role of podoplanin and CLEC-2 in COVID-19. Methods: Circulating levels of podoplanin and CLEC-2 were measured in 30 consecutive COVID-19 patients admitted due to hypoxia, and in 30 age- and sex-matched healthy individuals. Podoplanin expression in lungs from patients who died of COVID-19 was obtained from two independent public databases of single-cell RNAseq from which data from control lungs were also available. Results: Circulating podoplanin levels were lower in COVID-19, while no difference was observed in CLEC-2 levels. Podoplanin levels were significantly inversely correlated with markers of coagulation, fibrinolysis and innate immunity. scRNAseq data confirmed that PDPN is co-expressed with ACE2 in pneumocytes, and showed that PDPN expression is lower in this cell compartment in lungs from patients with COVID-19. Conclusion: Circulating levels of podoplanin are lower in COVID-19, and the magnitude of this reduction is correlated with hemostasis activation. We also demonstrate the downregulation of PDPN at the transcription level in pneumocytes. Together, our exploratory study questions whether an acquired podoplanin deficiency could be involved in the pathogenesis of acute lung injury in COVID-19, and warrant additional studies to confirm and refine these findings.

Are pediatricians familiar with hereditary angioedema?

Background: Hereditary angioedema (HAE) is an autosomal dominant disease characterized by recurrent episodes of subcutaneous or mucosal edema caused by excess bradykinin. The aim of the present study was to assess the knowledge of pediatricians about hereditary angioedema. Methods: An online survey with 12 HAE-related and 14 demographics-related questions was e-mailed to all pediatricians who were members of the Brazilian Society of Pediatrics (n = 17 145) once a week during the months of June and July 2021. The electronic questionnaire assessed clinical manifestations, diagnosis, and treatment of hereditary angioedema in children and adolescents. Results: Four hundred and fifty-five pediatricians responded to the questionnaire (2.6%), of whom 55 (12.1%) were board certified in Allergy and Immunology (A/I), while 400 (87.9%) were not (N-A/I). Three hundred and sixty-eight (80.9%) were female, 289 (55.7%) were under 50 years of age, 286 (62.9%) graduated from Medical School more than 10 years previously, 83 (18.2%) held an MSc/PhD degree, and 253 (55.6%) were living in the Southeast Region of Brazil. The median number of correct answers to the questions related to HAE among A/I was 7 out of 12 (58.3%), with median ranging from 4.5 to 8 correct answers, while for N-A/I it was 3 (25%), with median ranging from 2.5 to 4 correct answers (p < 0.001). Conclusion: Knowledge about HAE among Brazilian pediatricians, whether board certified in Allergy and Immunology or not, was unsatisfactory. HAE is a rare disease, largely unknown among physicians; therefore, increasing awareness may lead to improvement in diagnosis and treatment.

SARS-CoV-2 uses CD4 to infect T helper lymphocytes.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS- CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.

Plasma Angiotensin II Is Increased in Critical Coronavirus Disease 2019.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) employs angiotensin-converting enzyme 2 (ACE2) as its receptor for cell entrance, and studies have suggested that upon viral binding, ACE2 catalytic activity could be inhibited; therefore, impacting the regulation of the renin-angiotensin-aldosterone system (RAAS). To date, only few studies have evaluated the impact of SARS-CoV-2 infection on the blood levels of the components of the RAAS. The objective of this study was to determine the blood levels of ACE, ACE2, angiotensin-II, angiotensin (1-7), and angiotensin (1-9) at hospital admission and discharge in a group of patients presenting with severe or critical evolution of coronavirus disease 2019 (COVID-19). We showed that ACE, ACE2, angiotensin (1-7), and angiotensin (1-9) were similar in patients with critical and severe COVID-19. However, at admission, angiotensin-II levels were significantly higher in patients presenting as critical, compared to patients presenting with severe COVID-19. We conclude that blood levels of angiotensin-II are increased in hospitalized patients with COVID-19 presenting the critical outcome of the disease. We propose that early measurement of Ang-II could be a useful biomarker for identifying patients at higher risk for extremely severe progression of the disease.

Contact and intrinsic coagulation pathways are activated and associated with adverse clinical outcomes in COVID-19.

Coagulation activation is a prominent feature of severe acute respiratory syndrome coronavirus 2 (COVID-19) infection. Activation of the contact system and intrinsic pathway has increasingly been implicated in the prothrombotic state observed in both sterile and infectious inflammatory conditions. We therefore sought to assess activation of the contact system and intrinsic pathway in individuals with COVID-19 infection. Baseline plasma levels of protease:serpin complexes indicative of activation of the contact and intrinsic pathways were measured in samples from inpatients with COVID-19 and healthy individuals. Cleaved kininogen, a surrogate for bradykinin release, was measured by enzyme-linked immunosorbent assay, and extrinsic pathway activation was assessed by microvesicle tissue factor-mediated factor Xa (FXa; MVTF) generation. Samples were collected within 24 hours of COVID-19 diagnosis. Thirty patients with COVID-19 and 30 age- and sex-matched controls were enrolled. Contact system and intrinsic pathway activation in COVID-19 was demonstrated by increased plasma levels of FXIIa:C1 esterase inhibitor (C1), kallikrein:C1, FXIa:C1, FXIa:α1-antitrypsin, and FIXa:antithrombin (AT). MVTF levels were also increased in patients with COVID-19. Because FIXa:AT levels were associated with both contact/intrinsic pathway complexes and MVTF, activation of FIX likely occurs through both contact/intrinsic and extrinsic pathways. Among the protease:serpin complexes measured, FIXa:AT complexes were uniquely associated with clinical indices of disease severity, specifically total length of hospitalization, length of intensive care unit stay, and extent of lung computed tomography changes. We conclude that the contact/intrinsic pathway may contribute to the pathogenesis of the prothrombotic state in COVID-19. Larger prospective studies are required to confirm whether FIXa:AT complexes are a clinically useful biomarker of adverse clinical outcomes.

Increased Serum Mir-150-3p Expression Is Associated with Radiological Lung Injury Improvement in Patients with COVID-19.

Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus, responsible for an atypical pneumonia that can progress to acute lung injury. MicroRNAs are small non-coding RNAs that control specific genes and pathways. This study evaluated the association between circulating miRNAs and lung injury associated with COVID-19. Methods: We evaluated lung injury by computed tomography at hospital admission and discharge and the serum expression of 754 miRNAs using the TaqMan OpenArray after hospital discharge in 27 patients with COVID-19. In addition, miR-150-3p was validated by qRT-PCR on serum samples collected at admission and after hospital discharge. Results: OpenArray analysis revealed that seven miRNAs were differentially expressed between groups of patients without radiological lung improvement compared to those with lung improvement at hospital discharge, with three miRNAs being upregulated (miR-548c-3p, miR-212-3p, and miR-548a-3p) and four downregulated (miR-191-5p, miR-151a-3p, miR-92a-3p, and miR-150-3p). Bioinformatics analysis revealed that five of these miRNAs had binding sites in the SARS-CoV-2 genome. Validation of miR-150-3p by qRT-PCR confirmed the OpenArray results. Conclusions: The present study shows the potential association between the serum expression of seven miRNAs and lung injury in patients with COVID-19. Furthermore, increased expression of miR-150 was associated with pulmonary improvement at hospital discharge.

Asthma and COVID-19: a systematic review.

BACKGROUND: Severe coronavirus disease-19 (COVID-19) presents with progressive dyspnea, which results from acute lung inflammatory edema leading to hypoxia. As with other infectious diseases that affect the respiratory tract, asthma has been cited as a potential risk factor for severe COVID-19. However, conflicting results have been published over the last few months and the putative association between these two diseases is still unproven. METHODS: Here, we systematically reviewed all reports on COVID-19 published since its emergence in December 2019 to June 30, 2020, looking into the description of asthma as a premorbid condition, which could indicate its potential involvement in disease progression. RESULTS: We found 372 articles describing the underlying diseases of 161,271 patients diagnosed with COVID-19. Asthma was reported as a premorbid condition in only 2623 patients accounting for 1.6% of all patients. CONCLUSIONS: As the global prevalence of asthma is 4.4%, we conclude that either asthma is not a premorbid condition that contributes to the development of COVID-19 or clinicians and researchers are not accurately describing the premorbidities in COVID-19 patients.

Hereditary angioedema: how to approach it at the emergency department?

Angioedema attacks are common causes of emergency care, and due to the potential for severity, it is important that professionals who work in these services know their causes and management. The mechanisms involved in angioedema without urticaria may be histamine- or bradykinin-mediated. The most common causes of histamine-mediated angioedema are foods, medications, insect sting and idiopathic. When the mediator is bradykinin, the triggers are angiotensin-converting enzyme inhibitors and factors related to acquired angioedema with deficiency of C1-inhibitor or hereditary angioedema, which are less common, but very important because of the possibility of fatal outcome. Hereditary angioedema is a rare disease characterized by attacks of edema that affect the subcutaneous tissue and mucous membranes of various organs, manifesting mainly by angioedema and abdominal pain. This type of angioedema does not respond to the usual treatment with epinephrine, antihistamines and corticosteroids. Thus, if not identified and treated appropriately, these patients have an estimated risk of mortality from laryngeal edema of 25% to 40%. Hereditary angioedema treatment has changed dramatically in recent years with the development of new and efficient drugs for attack management: plasma-derived C1 inhibitor, recombinant human C1-inhibitor, bradykinin B2 receptor antagonist (icatibant), and the kallikrein inhibitor (ecallantide). In Brazil, plasma-derived C1 inhibitor and icatibant have already been approved for use. Proper management of these patients in the emergency department avoids unnecessary surgery and, especially, fatal outcomes.

Evaluation of the efficacy and safety of icatibant and C1 esterase/kallikrein inhibitor in severe COVID-19: study protocol for a three-armed randomized controlled trial.

BACKGROUND: SARS-CoV-2, the virus that causes COVID-19, enters the cells through a mechanism dependent on its binding to angiotensin-converting enzyme 2 (ACE2), a protein highly expressed in the lungs. The putative viral-induced inhibition of ACE2 could result in the defective degradation of bradykinin, a potent inflammatory substance. We hypothesize that increased bradykinin in the lungs is an important mechanism driving the development of pneumonia and respiratory failure in COVID-19. METHODS: This is a phase II, single-center, three-armed parallel-group, open-label, active control superiority randomized clinical trial. One hundred eighty eligible patients will be randomly assigned in a 1:1:1 ratio to receive either the inhibitor of C1e/kallikrein 20 U/kg intravenously on day 1 and day 4 plus standard care; or icatibant 30 mg subcutaneously, three doses/day for 4 days plus standard care; or standard care alone, as recommended in the clinical trials published to date, which includes supplemental oxygen, non-invasive and invasive ventilation, antibiotic agents, anti-inflammatory agents, prophylactic antithrombotic therapy, vasopressor support, and renal replacement therapy. DISCUSSION: Accumulation of bradykinin in the lungs is a common side effect of ACE inhibitors leading to cough. In animal models, the inactivation of ACE2 leads to severe acute pneumonitis in response to lipopolysaccharide (LPS), and the inhibition of bradykinin almost completely restores the lung structure. We believe that inhibition of bradykinin in severe COVID-19 patients could reduce the lung inflammatory response, impacting positively on the severity of disease and mortality rates. TRIAL REGISTRATION: Brazilian Clinical Trials Registry Universal Trial Number (UTN) U1111-1250-1843. Registered on May/5/2020.

Rapid clinical recovery of a SARS-CoV-2 infected common variable immunodeficiency patient following the infusion of COVID-19 convalescent plasma.

BACKGROUND: Common variable immunodeficiency is the most prevalent symptomatic primary immunodeficiency in adults. Affected patients fail to mount an appropriate humoral response against community acquired infectious diseases and recent reports have provided data supporting the increased susceptibility of these patients to severe SARS-CoV-2 infections. In this context, the infusion of COVID-19 convalescent plasma could represent an effective therapeutic strategy. CASE PRESENTATION: 25-year old woman diagnosed with common variable immunodeficiency in 2013, developed severe COVID-19 that rapidly progressed to pneumonia presenting with multiple bilateral lung opacities that were both central and peripheral and presented as ground-glass and consolidation types involving all lobes, bilaterally. As blood oxygen saturation decayed and lung abnormalities were not responsive to large spectrum antibiotics and corticosteroids, patient was placed on mechanical ventilation and compassionate-use of approved COVID-19 convalescent donor plasma was introduced. The patient presented a rapid response to the approach and mechanical ventilation could be interrupted 24 h after first dose of COVID-19 convalescent donor plasma. As a whole, the patient received four doses of 200 mL convalescent plasma during a period of 6 days. There was rapid improvement of clinical status, with interruption of supplemental oxygen therapy after 6 days and reduction of lung abnormalities as evidence by sequential computed tomography scans. CONCLUSIONS: This is a single patient report that adds to other few reports on common variable immunodeficiency and agammaglobulinemia, suggesting that COVID-19 convalescent donor plasma could be a valuable therapeutic approach to treat patients affected by dysgammaglobulinemias and presenting severe COVID-19.