The Janus faces of acquired angioedema: C1-inhibitor deficiency, lymphoproliferation and autoimmunity

The Occurrence of Atopy in Patients with Isolated Spontaneous Mast Cell (or Nonallergic) Angioedema

BACKGROUND

Isolated mast cell angioedema (MC-AE) can be divided into allergic and nonallergic (spontaneous) forms. The former is often associated with food, Hymenoptera venoms or drug allergies. This study aimed to evaluate the relationship between the occurrence of atopic diseases and the risk of angioedema.

METHODS

A retrospective study analyzed 304 patients with confirmed MC-AE and 1066 controls. All were analyzed for allergic asthma (AA), atopic dermatitis (AD) and allergic rhinitis (AR) based on ICD-10 codes. In addition, total IgE and peripheral eosinophilia were calculated.

RESULTS

The analyzed atopic diseases were more frequent in the group of patients diagnosed with MC-AE than in the controls: 78 (25.7%) vs. 173 (16.2%) for p < 0.01. Patients diagnosed with AD had a higher risk of MC-AE (hazard ratio (HR) = 1.48,) similar to those diagnosed with AR (HR = 1.51). However, in patients with two or three atopic comorbidities, the risk increased significantly to HR = 2.45 or HR = 4.1, respectively. There was a positive correlation between the serum total IgE concentration or eosinophilia and the risk of angioedema (p < 0.01).

CONCLUSION

Patients with MC-AE had a more frequent occurrence of atopic diseases associated with inhalant allergies. This risk increased in patients with IgE-mediated polymorphic disease.

Acquired Angioedema Due to C1-Inhibitor Deficiency (AAE-C1-INH)-A Bicenter Retrospective Study on Diagnosis, Course, and Therapy

BACKGROUND

Acquired angioedema with C1-inhibitor deficiency (AAE-C1-INH) is a rare condition resembling hereditary angioedema (HAE), but with late onset and low C1-inhibitor (C1-INH) due to consumption potentially caused by autoimmune diseases and mainly lymphatic malignancies. Being about 10-fold rarer than HAE, there is limited knowledge and no licensed therapy.

OBJECTIVE

To report clinical and biological data from a newly described population of 20 patients with AAE-C1-INH assessing diagnostic delay, AAE-C1-INH:HAE-ratio, underlying conditions, and therapeutic management in Germany.

METHODS

Retrospective data analysis of 20 patients from 2 angioedema centers in southern Germany.

RESULTS

Median age at symptoms' onset was 64 years (60% females), with predominant swellings of the face (85%) and low levels for C1-INH in almost all patients. The ratio AAE-C1-INH:HAE was 1:9.7. From symptoms' onset to diagnosis of AAE-C1-INH, the median delay was 7.5 months, and between AAE-C1-INH symptoms' onset and diagnosis of the underlying hematological condition (n = 9) it was 4 months (median). Four patients had a history of solid neoplasm, 1 had a papillary thyroid carcinoma as the only potential cause for AAE-C1-INH, with treatment of the malignancy resulting in resolution of AAE-C1-INH. All the symptomatic patients were treated with off-label on-demand icatibant subcutaneously or C1-INH concentrate intravenously, and 6 severely affected patients needed off-label long-term prophylaxis with good symptom control.

CONCLUSIONS

AAE-C1-INH is characterized by late-onset swellings mainly involving the face and low C1-INH levels. Diagnostic delay for AAE-C1-INH is further decreasing despite being about 10-fold rarer than HAE. Patients severely affected without underlying condition or no indication for treatment could benefit from off-label therapy.

Acquired Angioedema in Selected Neoplastic Diseases

Background and Objectives. Acquired angioedema is a relatively common revelation accompanying some diseases such as autoimmune or cancer. The study aimed to assess the incidence of one subtype of angioedema-C1-INH-AAE (acquired angioedema with C1 inhibitor deficiency). Material and methods. The study was retrospective and based on 1 312 patients with a final diagnosis of breast cancer, colorectal cancer, or lung cancer: 723 women and 589 men with a mean age of 58.2 ± 13.5 years. The cancer diagnosis according to the ICD (International Classification of Diseases)-10 code, medical history including TNM (Tumour, Node, Metastasis) staging, histopathology, and assessment of the occurrence of C1-INH-AAE angioedema were analysed. Results. C1-INH-AAE occurred more often in patients with cancer than in the control group, as follows: 327 (29%) vs. 53 (6%) for p < 0.05. C1-INH-AAEs were observed most often in the group of patients diagnosed with breast cancer compared to colorectal and lung groups: 197 (37%) vs. 108 (26%) vs. 22 (16%) (p < 0.05). A higher incidence of C1-INH-AAE was observed in the early stages of breast cancer. However, there was no relationship between the occurrence of C1-INH-AAE and the BRCA1 (Breast Cancer gene 1)/BRCA2 (Breast Cancer gene 2) mutation or histopathological types of breast cancer. Conclusion. Angioedema type C1-INH-AAE occurs more often in patients with selected neoplastic diseases, especially in the early stages of breast cancer.

[Angioedema without Urticaria: Medical History and Findings]

Angioedema without Urticaria: Medical History and Findings Abstract. Abstracts: We present the case of a woman with repeated attacks of angioedema without wheals. Given that there was no benefit from systemic steroid and antihistamines therapy, we interpretated the clinical picture as bradykinin- (and not histamine-) induced. Owing to the late onset and a negative family history, we suspected a case of angioedema due to acquired C1-INH deficiency. This hypothesis was later confirmed by specific hematological tests. We therefore started a specific prophylaxis and therapy in case of acute attacks.

Presentation of an extraordinary colic: abdominal pain as the first and only utterance of an acquired C1-inhibitor deficiency

C1-inhibitor deficiency is a rare disease which incorporates acute self-limiting intermittent swelling of the subcutaneous tissue and mucous membranes. Attacks most frequently affect the face and/or the upper airway. Isolated angioedema of the small bowel is an uncommon manifestation and often accompanied by diagnostic delay. In the present case, abdominal pain turned out to be the first and only utterance of an acquired C1-inhibitor deficiency, secondary to a splenic marginal zone lymphoma. Imaging showed wall thickening of the small intestine, ascites and splenomegaly. The abdominal pain and intestinal wall thickening with surrounding ascites on imaging spontaneously resolved each episode within 2-3 days. Gastrointestinal manifestations of angioedema may mimic an acute abdomen, and subsequently one-third of these patients undergo unnecessary surgery prior to a definite diagnosis. This emphasises the importance of considering the diagnosis in case of an 'extraordinary colic'.

Angioedema Without Wheals: Challenges in Laboratorial Diagnosis

Angioedema is a prevailing symptom in different diseases, frequently occurring in the presence of urticaria. Recurrent angioedema without urticaria (AE) can be hereditary (HAE) and acquired (AAE), and several subtypes can be distinguished, although clinical presentation is quite similar in some of them. They present with subcutaneous and mucosal swellings, affecting extremities, face, genitals, bowels, and upper airways. AE is commonly misdiagnosed due to restricted access and availability of appropriate laboratorial tests. HAE with C1 inhibitor defect is associated with quantitative and/or functional deficiency. Although bradykinin-mediated disease results mainly from disturbance in the kallikrein–kinin system, traditionally complement evaluation has been used for diagnosis. Diagnosis is established by nephelometry, turbidimetry, or radial immunodiffusion for quantitative measurement of C1 inhibitor, and chromogenic assay or ELISA has been used for functional C1-INH analysis. Wrong handling of the samples can lead to misdiagnosis and, consequently, mistaken inappropriate approaches. Dried blood spot (DBS) tests have been used for decades in newborn screening for certain metabolic diseases, and there has been growing interest in their use for other congenital conditions. Recently, DBS is now proposed as an efficient tool to diagnose HAE with C1 inhibitor deficiency, and its use would improve the access to outbound areas and family members. Regarding HAE with normal C1 inhibitor, complement assays’ results are normal and the genetic sequencing of target genes, such as exon 9 of F12 and PLG, is the only available method. New methods to measure cleaved high-molecular-weight kininogen and activated plasma kallikrein have emerged as potential biochemical tests to identify bradykinin-mediated angioedema. Validated biomarkers of kallikrein–kinin system activation could be helpful in differentiating mechanisms of angioedema. Our aim is to focus on the capability to differentiate histaminergic AE from bradykinin-mediated AE. In addition, we will describe the challenges developing specific tests like direct bradykinin measurements. The need for quality tests to improve the diagnosis is well represented by the variability of results in functional assays.

Resolution of Laryngeal Oedema in a Patient with Acquired C1-Inhibitor Deficiency. a Case Report

Introduction

Laryngeal oedema caused by acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) is a life-threatening condition. The swelling is bradykinin mediated and will not respond to the usual treatment with antihistamines, corticosteroids, or epinephrine. Instead, kallikrein-bradykinin-targeted therapies should be used promptly to prevent asphyxiation.

Case presentation

A 43 years old female presented at the Hereditary Angioedema Centre reporting a one-year history of peripheral, facial, and neck oedema. Treatment with antihistamines and corticosteroids had been ineffective. Laboratory results showed complement level deficiencies and monoclonal gammopathy characterised as immunoglobulin M. An abdominal ultrasound revealed splenomegaly. A bone marrow biopsy was normal. Based on these data, the diagnosis of C1-INH-AAE associated with monoclonal gammopathy of uncertain significance (MGUS) was made. As C1-INH-AAE can present with life-threatening, standard treatment-resistant laryngeal oedema, an emergency care treatment plan was proposed, and the patient was advised to present to the emergency department (ED) with this medical letter. Based on these recommendations, three laryngeal attacks were successfully treated in the ED with recombinant human C1-inhibitor (two attacks) and fresh frozen plasma (one attack). After these episodes, the patient was prescribed prophylactic treatment with antifibrinolytics. No further angioedema attacks were reported by the patient at the 18 months follow-up visit.

Conclusions

Because angioedema of the upper airways is a life-threatening condition, recognising the specific type of swelling by the emergency physician is critical in providing immediate and effective treatment to reduce the associated risk of asphyxiation. C1-INH-AAE being a rare disorder, patients should have available an emergency care treatment plan with recommendations of acute treatment possibilities.

Acquired Angioedema Due to C1 inhibitor Deficiency Caused by Non-Hodgkin Lymphoma in a Patient with Myasthenia Gravis

Acquired angioedema due to C1-inhibitor deficiency is a very rare disorder that usually appears in patients with lymphoproliferative and/or autoimmune diseases. This type of swelling is bradykinin mediated and does not respond to antihistamines, corticosteroids, or epinephrine. The symptoms usually appear in patients older than 40 years with recurrent episodes of angioedema without wheals. The family history is negative. The swelling could affect any tissue, but most frequently is located at the face, lips, tongue, larynx, or extremities. In the gastrointestinal tract, it causes pain, nausea, vomiting, and diarrhea. The upper respiratory airway oedema is a potentially life-threatening condition due to asphyxiation. The oedema attacks may precede the symptoms of the causative disease for months or years. In most cases, the treatment of the underlying disease resolves the angioedema episodes. Here we report a case of C1-INH-AAE caused by non-Hodgkin lymphoma in a patient diagnosed many years before with myasthenia gravis whose angioedema symptoms resolved after the specific treatment of lymphoma.

Assessment of disease activity and quality of life in patients with recurrent bradykinin-mediated versus mast cell-mediated angioedema

Objective

Recurrent Angioedema (RAE) is characterized by sudden swelling of mucosal surfaces or deep dermis and is either mast cell-(MMAE) or bradykinin-mediated (BMAE). How patients with BMAE and MMAE differ in terms of disease activity and impact remains largely unknown. Here, we determined validity, reliability, and sensitivity to change of Turkish versions of angioedema activity score (AAS) and quality of life questionnaire (AE-QoL) and used both instruments to investigate and compare patients with BMAE and MMAE.

Methods

Turkish versions of AAS28 and AE-QoL were applied to 94 patients with RAE (18–72 years). Patients’ global self-assessment of QoL (PGA-QoL), disease activity (PGA-DA-VRS, PatGA-DA-VAS), and 12-Item-Short Form Survey were used at week 4 (visit 2), and week 8 (visit 3). Demographic characteristics, clinical features, and AAS28 and AE-QoL values were compared between 31 patients with BMAE and 63 patients with MMAE.

Results

Turkish AAS28 and AE-QoL showed excellent internal consistency, high reproducibility and known-groups validity. Compared to patients with MMAE, BMAE patients were younger (34.6 ± 10.7 vs. 40.7 ± 13.3 years), had longer disease duration (236 ± 178 vs. 51 ± 78 months), high prevalence of family history (63% vs 14%), longer duration of attacks (65 ± 20 vs. 40 ± 25 h), and they were more commonly affected by upper airway angioedema (70% vs 23%). Disease activity (AAS28) was lower (29.3 ± 24.6 vs 55.2 ± 52.9), but AE-QoL was higher (44.2 ± 16.1 vs 34.5 ± 22.5) in BMAE patients as compared to MMAE patients.

Conclusions

Patients with BMAE and MMAE have distinct disease characteristics. Recurrent bradykinin-mediated angioedema impacts quality of life more than mast cell-mediated angioedema. The discriminating characteristics of patients with BMAE and MMAE may help to improve the diagnosis and management of patients with RAE.

Chronic Urticaria and Recurrent Angioedema: Clues to the Mimics

Urticaria and angioedema are experienced by up to 1 in 5 people, usually the result of common allergen or medication triggers and infections. Similarly, the majority of recurrent angioedema has an exogenous trigger, for example, angiotensin converting enzyme inhibitors, or is hereditary (type 1 and 2 hereditary angioedema); chronic spontaneous urticaria are most often autoimmune or autoallergic in routine clinical practice. There are, however, several skin and systemic conditions that can imitate the clinical appearance of either angioedema or urticaria, whereas there are several uncommon conditions that have chronic urticaria and/or recurrent angioedema as part of their disease manifestations. Correct diagnosis is paramount to ensuring subsequent tailored therapy for many of these conditions, and in many instances, diagnostic delay can be several years with morbid consequence. In this grand rounds article, we present 2 illustrative clinical cases as the backdrop to discussing a practical diagnostic approach for clinicians to recognize copycat phenotypes and "red flags" that should prompt further investigation of several uncommon mimics. We highlight key diagnostic features, epidemiology, and management for mimics where treatment is distinct from the common phenotypes of recurrent angioedema and chronic urticarias.

Managing Chronic Urticaria and Recurrent Angioedema Differently with Advancing Age

Angioedema and urticaria affect people of all ages. Accurate diagnosis and optimum management is essential for healthy aging. Older people continue to experience mast cell-mediated urticaria and angioedema, with a higher prevalence of autoimmune and a lower prevalence of autoallergic disease. Bradykinin-mediated angioedemas are more common in the elderly because of their association with angiotensin-converting enzyme inhibitor (ACEI) treatment. Acquired C1-inhibitor deficiency, another bradykinin-mediated angioedema, occurs predominantly in older people, whereas hereditary angioedema due to C1-inhibitor deficiency continues to cause symptoms, even in old age. Drug-induced angioedemas disproportionately affect older people, the most frequent users of ACEIs, aspirin, and nonsteroidal anti-inflammatory drugs. Accurate diagnosis and targeted treatment prevent unnecessary morbidity and mortality. Second-generation antihistamines with omalizumab if required are effective and well tolerated in older people with mast cell-mediated urticaria. For bradykinin-mediated angioedemas, these drugs are ineffective. C1-inhibitor replacement or blockade of kallikrein or the bradykinin B2 receptor of the contact pathway is required to treat hereditary angioedema and may be considered in other bradykinin-mediated angioedemas, if supportive treatment is insufficient. For aspirin-related angioedema and urticaria, alternative medications or, exceptionally, desensitization may be required.

The Immunopathology of Complement Proteins and Innate Immunity in Autoimmune Disease

The complement is a powerful cascade of the innate immunity and also acts as a bridge between innate and acquired immune defence. Complement activation can occur via three distinct pathways, the classical, alternative and lectin pathways, each resulting in the common terminal pathway. Complement activation results in the release of a range of biologically active molecules that significantly contribute to immune surveillance and tissue homeostasis. Several soluble and membrane-bound regulatory proteins restrict complement activation in order to prevent complement-mediated autologous damage, consumption and exacerbated inflammation. The crucial role of complement in the host homeostasis is illustrated by association of both complement deficiency and overactivation with severe and life-threatening diseases. Autoantibodies targeting complement components have been described to alter expression and/or function of target protein resulting in a dysregulation of the delicate equilibrium between activation and inhibition of complement. The spectrum of diseases associated with complement autoantibodies depends on which complement protein and activation pathway are targeted, ranging from autoimmune disorders to kidney and vascular diseases. Nevertheless, these autoantibodies have been identified as differential biomarkers for diagnosis or follow-up of disease only in a small number of clinical conditions. For some autoantibodies, a clear relationship with clinical manifestations has been identified, such as anti-C1q, anti-Factor H, anti-C1 Inhibitor antibodies and C3 nephritic factor. For other autoantibodies, the origin and the functional consequences still remain to be elucidated, questioning about the pathophysiological significance of these autoantibodies, such as anti-mannose binding lectin, anti-Factor I, anti-Factor B and anti-C3b antibodies. The detection of autoantibodies targeting complement components is performed in specialized laboratories; however, there is no consensus on detection methods and standardization of the assays is a real challenge. This review summarizes the current panorama of autoantibodies targeting complement recognition proteins of the classical and lectin pathways, associated proteases, convertases, regulators and terminal components, with an emphasis on autoantibodies clearly involved in clinical conditions.

The central role of endothelium in hereditary angioedema due to C1 inhibitor deficiency

An impairment of the endothelial barrier function underlies a wide spectrum of pathological conditions. Hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) can be considered the "pathophysiological and clinical paradigm" of Paroxysmal Permeability Diseases (PPDs), conditions characterized by recurrent transient primitively functional alteration of the endothelial sieving properties, not due to inflammatory-ischemic-degenerative injury and completely reversible after the acute flare. It is a rare yet probably still underdiagnosed disease which presents with localized, non-pitting swelling of the skin and submucosal tissues of the upper respiratory and gastrointestinal tracts, without significant wheals or pruritus. The present review addresses the pathophysiology of C1-INH-HAE with a focus on the crucial role of the endothelium during contact and kallikrein/kinin system (CAS and KKS) activation, currently available and emerging biomarkers, methods applied to get new insights into the mechanisms underlying the disease (2D, 3D and in vivo systems), new promising investigation techniques (autonomic nervous system analysis, capillaroscopy, flow-mediated dilation method, non-invasive finger plethysmography). Hints are given to the binding of C1-INH to endothelial cells. Finally, crucial issues as the local vs systemic nature of CAS/KKS activation, the episodic nature of attacks vs constant C1-INH deficiency, pros and cons as well as future perspectives of available methodologies are briefly discussed.

A Case of Acquired Angioedema with Low C1 Inhibitor (C1-INH) Associated with Splenic Marginal Zone Lymphoma

Patient: Male, 68

Final Diagnosis: AAE

Symptoms: Angioedema

Medication: —

Clinical Procedure: —

Specialty: Hematology

Serum complexes between C1INH and C1INH autoantibodies for the diagnosis of acquired angioedema

Acquired angioedema due to C1-inhibitor (C1INH) deficiency (AAE) is caused by secondary C1INH deficiency leading to bradykinin-mediated angioedema episodes. AAE typically presents in adulthood and is associated with B cell lymphoproliferation. Anti-C1INH autoantibodies (antiC1INHAbs) are detectable in a subset of AAE cases and considered a hallmark of the disease. When free antiC1INHAbs and malignant tumors are not detectable, diagnosis relies on the finding of low C1INH levels and/or function, lack of family history and SERPING1 mutations, age at onset and low or undetectable C1q levels, none of which is specific for AAE. We tested the diagnostic value of a novel enzyme-linked immunosorbent assay (ELISA) for the detection of circulating complexes between C1INH and antiC1INHAbs (C1INH-antiC1INHAb) in the serum of 20 European AAE patients characterized on the basis of their complement levels and function. Free antiC1INHAbs were detected in nine of 20 patients [six of immunoglobulin (Ig)G class, two of IgM class and one simultaneously presenting IgG and IgM classes], whereas C1INH-antiC1INHAb complexes were found in 18 of 20 of the AAE cases, regardless of the presence or absence of detectable free anti-C1INHAbs. Of note, nine of 20 patients showed negative free antiC1INHabs, but positive C1INH-antiC1INHAb complexes in their first measurement. In the cohort presented, IgM-class C1INH-antiC1INHAb are specifically and strongly associated with low C1q serum levels. Detection of C1INH-antiC1-INHAbs provides an added value for AAE diagnosis, especially in those cases in whom no free anti-C1INH antibodies are detected. The link between IgM-class C1INH-antiC1INHAb complexes and C1q consumption could have further implications for the development of autoimmune manifestations in AAE.

Coagulation and Skin Autoimmunity

Several lines of evidence indicate that the immune system, inflammation, and coagulation are simultaneously activated in autoimmune and immune-mediated skin diseases. Pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha induce the expression of the main initiator of coagulation, i.e., tissue factor. The proteases of coagulation in turn act on protease-activated receptors inducing the expression of various pro-inflammatory cytokines triggering inflammation. The cross-talk among immune system, inflammation, and coagulation amplifies and maintains the activation of all three pathways. This review focuses on three skin disorders as chronic spontaneous urticaria (CSU), angioedema, and bullous pemphigoid (BP), in which the relationships among the three systems have been investigated or their clinical consequences are relevant. Markers of thrombin generation, fibrinolysis, and inflammation have been reported to be increased in the plasma during flares of CSU and angioedema, as well as in the active phase of BP, with the marker levels reverting to normal during remission. The coagulation activation seems to be important only at local level in CSU and angioedema while both at local and systemic levels in BP which is the only condition associated with an increased thrombotic risk. The prothrombotic state in autoimmune skin diseases raises the question of the indication of anticoagulant treatment, particularly in the presence of other cardiovascular risk factors.

Isolated angioedema: An overview of clinical features and etiology

Angioedema can occur in isolation, accompanied by urticaria, or as a feature of anaphylaxis in mast cell-mediated disorders, bradykinin-mediated disorders, as well as in others with unknown mechanisms, such as infections, rare disorders, or idiopathic angioedema. In mast cell-mediated angioedema, other signs and symptoms of mast cell-mediator release are frequently seen. However, clear evidence of mast cell degranulation may be absent in histaminergic angioedema. Bradykinin-induced angioedema is not associated with urticaria or other symptoms of type I hypersensitivity reactions. For many of the known triggers of angioedema, the mechanism is unclear. While mast cell and bradykinin-mediated angioedema are relatively well defined in terms of diagnostic and therapeutic approach, angioedema with unknown mechanisms represents a challenge for patients and clinicians alike. Elucidating the clinical pattern and the possible causes of isolated angioedema is the key to a correct diagnosis. This review summarizes the causes, and clinical features of angioedema, with a focus on isolated angioedema.

The physician and hereditary angioedema friend or foe: 62-year diagnostic delay and iatrogenic procedures

Background

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare autosomal dominant disease characterized by episodes of acute subcutaneous swelling, and/or recurrent severe abdominal pain. The disease is potentially fatal if the upper-airway is involved. Iatrogenic harm can occur if HAE is not considered in the differential diagnosis, the specialists are not aware of the natural history, diagnosis and treatment of HAE, or as a result of unnecessary surgical and other iatrogenic interventions.

Case presentation

We present the case of a 72-year-old man who began suffering recurrent abdominal pain at the age of 8 years. The pain led to frequent emergency department visits, three emergency surgical interventions, and 5 endoscopies before C1-INH-HAE was diagnosed at the age of 70. Infrequent subcutaneous swellings were attributed to unknown allergic reactions that were not related to the primary diagnosis of abdominal pain. Family history was positive for recurrent abdominal pain and angioedema but was ignored until the propositus’ grandson developed recurrent severe oro-facial edema attacks. The boy’s mother searched the worldwide web and found educational materials on a patient association website. She suggested complement C4 and C1-INH testing that led to the appropriate diagnosis of C1-INH-HAE type 1 in her son and his grandfather.

Conclusion

This report emphasizes the importance of accurately evaluating personal and family history in patients with a long history of recurrent, acute, severe but medically unexplained abdominal pain and cutaneous swellings. Here, the diagnosis of HAE was overlooked for 62 years and the focus on abdominal complaints led to numerous surgical interventions without consideration of the full differential diagnosis. Screening family members from all generations for unrecognized angioedema, abdominal pain, and measurement of C1-INH and C4 are essential for accurate and timely diagnosis of HAE.

Splenic marginal zone lymphomas in acquired C1-inhibitor deficiency: clinical and molecular characterization

Angioedema due to acquired deficiency of the inhibitor of the first component of complement (C1-INH) is a rare disease known as acquired angioedema (AAE). About 70% of patients with AEE display autoantibodies to C1-INH, the remaining patients have no antibodies to C1-INH. The clinical features of C1-INH deficiency include recurrent, self-limiting local swellings involving the skin, the gastrointestinal tract, and the upper respiratory tract. Swelling is due to accumulation of bradykinin released from high molecular weight kininogen. Patients with angioedema due to acquired C1 inhibitor deficiency (AEE) often have an associated lymphoproliferative disease including Non-Hodgkin Lymphomas (NHL). Among AAE patients with NHL, splenic marginal zone lymphoma (SMZL) has a higher prevalence (66%) compared to general population (2%) In the present study, we focused on patients with SMZL in AAE. We found 24 AAE patients with NHL and, among them 15 SMZL (62.5% of all NHL). We found NOTCH 2 activation in 4 /15 patients (26.6%) with SMZL, while no patients carried MYD 88 or BIRC3 mutations. Restricted immunoglobulin gene repertoire analysis showed that the IGHV1-2*04 allele was found to be over-represented in the group of patients with or without lymphoproliferative disease presenting with autoantibodies to C1-INH (41 of 55 (75%) of patients; p value 0.011) when compared to the control group of patients with AEE without antibodies to C1-INH, (7 of 27 (26%) of patients). Immunophenotyping failed to demonstrate the presence of autoreactive clones against C1-inhibitor. Taken together, these findings suggest a role for antigenic stimulation in the pathogenesis of lymphomas associated with AEE.

Long-term moderate exercise enhances specific proteins that constitute neurotrophin signaling pathway: A TMT-based quantitative proteomic analysis of rat plasma

Physical exercise has been reported to increase neurotrophin in brain tissues as hippocampus as well as increased neurotrophic level peripherally in blood plasma and might have an effect on/or affect molecular processes of energy metabolism (and homeostasis). In this study, using quantitative proteomic analysis, we obtained a plasma protein profile from the rat with long-term moderate exercise. A total of 752 proteins were identified in the plasma. Among them, 54 proteins were significant up-regulated and 47 proteins were down-regulated in the plasma of exercise group compared with the control group. Bioinformatic analyses showed that these altered proteins are widely involved in multiple biological processes, molecular functions and cellular components, which connect with 11 signaling pathways. Interestingly, 5 up-regulated proteins Rap1b, PTPN11, ARHGDIA, Cdc42 and YWHAE, confirmed by Western blots, are involved in the neurotrophin signaling pathway which shows the lowest P value among the identified pathways. Further analyses showed that the 5 neurotrophin-signaling-pathway-related proteins participate in two important protein-protein interaction networks associated to cell survival and apoptosis, axonal development, synapse formation and plasticity. This study provides an exercise-induced plasma protein profile, suggesting that long-term exercise enhances the proteins involved in neurotrophin signaling pathway which may contribute to health benefit.

SIGNIFICANCE

Physical activity contributes to myriad benefits on body health across the lifespan. The changes in plasma proteins after chronic moderate exercise may be used as biomarkers for health and may also play important roles in increase of cardiovascular fitness, enhancement of immune competence, prevention of obesity, decrease of risk for neurological disorders, cancer, stroke, diabetes and other metabolic disorders. Using a TMT-based proteomic method, this study identified 101 altered proteins in the plasma of rats after long-term moderate treadmill running, which may provide novel biomarkers for further investigation of the underlying mechanism of physical exercise. We confirmed that exercise enhances 5 proteins of the neurotrophin signaling pathway that may contribute to health benefits.

Refractory Abdominal Pain in a Patient with Chronic Lymphocytic Leukemia: Be Wary of Acquired Angioedema due to C1 Esterase Inhibitor Deficiency

Acquired angioedema due to C1 inhibitor deficiency (C1INH-AAE) is a rare and potentially fatal syndrome of bradykinin-mediated angioedema characterized by episodes of angioedema without urticaria. It typically manifests with nonpitting edema of the skin and edema in the gastrointestinal (GI) tract mucosa or upper airway. Edema of the upper airway and tongue may lead to life-threatening asphyxiation. C1INH-AAE is typically under-diagnosed because of its rarity and its propensity to mimic more common abdominal conditions and allergic reactions. In this article, we present the case of a 62-year-old male with a history of recently diagnosed chronic lymphocytic leukemia (CLL) who presented to our hospital with recurrent abdominal pain, initially suspected to have Clostridium difficile colitis and diverticulitis. He received a final diagnosis of acquired angioedema due to C1 esterase inhibitor deficiency due to concomitant symptoms of lip swelling, cutaneous nonpitting edema of his lower extremities, and complement level deficiencies. He received acute treatment with C1 esterase replacement and icatibant and was maintained on C1 esterase infusions. He also underwent chemotherapy for his underlying CLL and did not experience further recurrence of his angioedema.

Pediatric Angioedema

PURPOSE OF REVIEW

The aims of this study are to update the clinician on current understanding of angioedema as it presents in the pediatric population and to review proper diagnostic techniques and treatment modalities for various types of angioedema.

RECENT FINDINGS

Angioedema is still best classified by whether it is likely histaminergic or kinin-mediated. New guidelines have been published around the world to help diagnose and treat both forms (urticaria/angioedema and hereditary angioedema). The vast majority of the studies on treatment have been conducted in the adult population; however, there are data available in the pediatric population. In the realm of hereditary angioedema, there are multiple new therapies that have been studied in the pediatric population (down to 2 years in some studies) in recent years and offer the clinician options for treatment. Angioedema (whether occurring with or without urticaria) is common in the pediatric population. The majority of the recent studies has been conducted in hereditary angioedema, and now, the clinician should have various options to treat all forms of angioedema. Many treatment options, especially for hereditary angioedema, are further being examined specifically in the pediatric population.

Acquired C1 Inhibitor Deficiency

Acquired angioedema due to C1-INH deficiency (C1-INH-AAE) can occur when there are acquired (not inherited) deficiencies of C1-INH. A quantitative or functional C1-INH deficiency with negative family history and low C1q is diagnostic of C1-INH-AAE. The most common conditions associated with C1-INH-AAE are autoimmunity and B-cell lymphoproliferative disorders. A diagnosis of C1-INH-AAE can precede a diagnosis of lymphoproliferative disease and confers an increased risk for developing non-Hodgkin lymphoma. Treatment focuses on symptom control with therapies that regulate bradykinin activity (C1-INH concentrate, icatibant, ecallantide, tranexamic acid, androgens) and treatment of any underlying conditions.

Bradykinin: Inflammatory Product of the Coagulation System

Episodic and recurrent local cutaneous or mucosal swelling are key features of angioedema. The vasoactive agents histamine and bradykinin are highly implicated as mediators of these swelling attacks. It is challenging to assess the contribution of bradykinin to the clinical expression of angioedema, as accurate biomarkers for the generation of this vasoactive peptide are still lacking. In this review, we will describe the mechanisms that are responsible for bradykinin production in hereditary angioedema (HAE) and the central role that the coagulation factor XII (FXII) plays in it. Evidently, several plasma parameters of coagulation change during attacks of HAE and may prove valuable biomarkers for disease activity. We propose that these changes are secondary to vascular leakage, rather than a direct consequence of FXII activation. Furthermore, biomarkers for fibrinolytic system activation (i.e. plasminogen activation) also change during attacks of HAE. These changes may reflect triggering of the bradykinin-forming mechanisms by plasmin. Finally, multiple lines of evidence suggest that neutrophil activation and mast-cell activation are functionally linked to bradykinin production. We put forward the paradigm that FXII functions as a ‘sensor molecule’ to detect conditions that require bradykinin release via crosstalk with cell-derived enzymes. Understanding the mechanisms that drive bradykinin generation may help to identify angioedema patients that have bradykinin-mediated disease and could benefit from a targeted treatment.

Angioedema Phenotypes: Disease Expression and Classification

Due to marked heterogeneity of clinical presentations, comprehensive knowledge of angioedema phenotypes is crucial for correct diagnosis and choosing the appropriate therapeutic approach. One of the ways to a meaningful clinical distinction can be made between forms of angioedema occurring "with or without wheals." Angioedema with wheals (rash) is a hallmark of urticaria, either acute or chronic, spontaneous or inducible. Angioedema without wheals may still be manifested in about 10 % of patients with urticaria, but it may also occur as a separate entity. Several classifications of angioedema as part of urticaria were published over time, while a latest one, released in 2014 (HAWK group consensus, see below), provided a classification of all forms of "angioedema without wheals" distinct from urticaria, which will be the focus of the present review. At this time, the HAWK consensus classification is the best in terms of covering the pathophysiology, mediators involved, angioedema triggers, and clinical expression. According to this classification, three types of hereditary angioedema (genetic C1-INH deficiency, normal C1-INH with factor XII mutations, and unknown origin) and four types of acquired angioedema (C1-INH deficiency, related to ACE inhibitors intake, idiopathic histaminergic, and idiopathic non-histaminergic) are presented. We will review the distinctive clinical features of each phenotype in details.