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

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

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

Gene Mutations Linked to Hereditary Angioedema in Solitary Angioedema Patients With Normal C1 Inhibitor

BACKGROUND

Chronic recurrent angioedema without wheals (CRA) with normal C1 inhibitor (C1-INH) that is unresponsive to antihistamines may involve patients with recurrent angioedema of unknown cause (ie, so-called non-histaminergic idiopathic angioedema) as well as patients with hereditary angioedema with normal C1-INH (HAEnCI) when HAEnCI occurs in only one family member.

OBJECTIVE

To identify patients with one of type of HAEnCI in a group of patients with CRA with normal C1-INH that was unresponsive to antihistamines.

METHODS

A total of 132 patients with CRA and normal C1-INH that was unresponsive to antihistamines underwent mutational and clinical analysis. The presence of hereditary angioedema-specific mutations in Factor XII, plasminogen, ANGPT1, KNG1, MYOF, and HS3ST6 genes was tested by Sanger sequencing. When an HAEnCI-causing mutation was identified, available asymptomatic relatives were genetically tested.

RESULTS

In 116 of 132 solitary patients with CRA (87.9%), none of the six HAEnCI-linked mutations could be found. Ten patients (7.6%) had the Factor XII mutation c.983C>A (p.T328K) and six (4.5%) the plasminogen mutation c.988A>G (p.K330E). Other mutations linked to HAEnCI were not found in this patient series. In the 16 families with HAEnCI, 11 asymptomatic carriers of one of the HAEnCI-linked mutations were identified.

CONCLUSIONS

A search for HAEnCI-linked mutations in patients with solitary CRA may lead to the detection of patients and families with HAEnCI. This is important because family members can be identified who are at risk for developing potentially life-threatening angioedema, although they were previously asymptomatic. Without genetic investigation, the risk for an HAEnCI would have remained undetected in these patients and asymptomatic relatives.

Idiopathic Angioedema: Current Challenges

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

Biologicals targeting type 2 immunity: Lessons learned from asthma, chronic urticaria and atopic dermatitis

During the last decades, progression of research has led to great achievements for treatment and therapy of several disabling disorders, particularly in the field of chronic inflammatory diseases. The increased knowledge of the molecular mechanisms operating in such diseases has represented the first step in this process, and the discovery of molecules able to interfere with the natural history of the diseases, has been the second. This review is focused on the effects of biologics on type 2 diseases such as asthma, chronic urticaria and atopic dermatitis, both biologics just approved for clinical application and also those that are currently undergoing clinical trials. We will also discuss aspects and emphasize clinical trials and recently published studies, as well as research that is currently in the progress, which will be highly relevant for basic immunologists. Likewise, we will cover aspects that are pertinent for clinical immunologists and highlight translational studies that are evaluating novel biologicals in animal models.

[Angioedema prophylaxis]

Angioedema is a spontaneous, edematous swelling of the deep layers of the skin or mucous membrane. Angioedema in the respiratory tract is potentially life-threatening. The classification of angioedema into mast-cell-mediated (e. g. urticaria) or bradykinin-mediated (e. g. hereditary angioedema) is important for correct and rational treatment. Generally, two therapeutic strategies are available for angioedema treatment. On-demand treatment of angioedema symptoms that already have emerged aims to stop the further development of the attack and, thus, limits the severity and duration of the attack. This strategy is well established in the treatment of patients with hereditary angioedema, whereas in chronic spontaneous urticaria on-demand therapy plays no role in the guideline recommendations. In contrast, the therapeutic strategy of prophylaxis aims to prevent the occurrence of spontaneous and induced attacks as far as possible. Prophylaxis is the sole therapy strategy for chronic urticaria and is applied at all stages of the treatment algorithm. In the case of hereditary angioedema, on-demand therapy can be complemented by prophylaxis after careful and individual indication. In hereditary angioedema, prophylaxis is currently gaining in importance due to improved treatment options. Patients who use a prophylactic regime are much less likely to be forced to wait for the unpredictable occurrence of an attack and then to react with an on-demand treatment. Prophylactic treatment takes place at times determined by the patient himself, in contrast to treatment on an as-needed basis. The loss of unpredictability is a decisive moment in improving the quality of life.