Omalizumab as alternative to chronic use of oral corticosteroids in severe asthma.

Systemic/oral corticosteroids (OCS) have been used for decades in the management of acute asthma exacerbations and chronically in patients with uncontrolled severe asthma. However, while OCS are effective at treating acute exacerbations, there is only empirical evidence regarding the efficacy of OCS at reducing the rate of exacerbations. Evidence, although scarce, is suggestive of high exacerbation rates in severe asthma patients even when receiving maintenance treatment with OCS. In addition, use of OCS is associated with undesirable effects. Despite all this, physicians have continued to use OCS for managing severe asthma and acute exacerbation due to the lack of availability of effective alternatives. Fortunately, in the last decade several biologics have been proven safe and effective for patients with uncontrolled severe asthma. This has led to the Global Initiative for Asthma (GINA) recommending the use of biologics, instead of maintenance OCS, in patients with severe asthma (GINA Step 5). These include one biologic targeting immunoglobulin E (IgE) (omalizumab), and different biologics targeting interleukin-5 (IL-5), the IL-5 receptor (IL-5R) or IL-4 receptor α-unit (IL-4R α), including mepolizumab (subcutaneous), reslizumab (intravenous), benralizumab (subcutaneous) and dupilumab (subcutaneous). Omalizumab for the treatment of severe allergic asthma reduces exacerbations, irrespective of blood eosinophil levels. Anti-IL-5/IL-5R biologics are indicated in patients with severe eosinophilic asthma and repetitive exacerbations, irrespective of the presence or absence of allergy. Recently, an anti-IL4Rα biologic has been approved by the FDA for eosinophilic phenotype or oral corticosteroid-dependent asthma. Finally, physicians should consider using biologics as an alternative to chronic OCS therapy.

Therapeutic implications of the IL-21: IL-4 receptor system in children with common variable immunodeficiency syndrome.

OBJECTIVES: Interleukin-21 (IL-21) has been shown to restore immunoglobulin production together with Interleukin-4 (IL-4) in common variable immunodeficiency syndrome (CVID). Here, we elucidate the functional and structural properties of the corresponding IL-21R : IL-4R system. PATIENTS AND METHODS: An in vitro cell culture system was established to study the molecular effects of IL-21 and IL-4 on B cell differentiation, class-switch recombination (CSR) and immunoglobulin (Ig) production in 32 paediatric patients with CVID. MHC haplotypes and the IL21 and IL21R gene were analysed by genotyping. Ternary complexes of the IL-21 respectively IL-4 receptor were set-up by homology modeling and ligand-interaction was examined by molecular dynamics (MD) simulation. RESULTS: Stimulation with IL-21, IL-4 and CD40L uniformly induced IgG and IgA production in B cells from all tested patients by initiation of both CSR and AID-independent Ig production. No mutations were found in the coding regions of the IL21 or IL21R genes and no distinct HLA allele or extended haplotype could be correlated with the amount of Ig production or the gene expression pattern induced by IL-21. MD simulations of the modelled receptor complexes showed that IL-4 and IL-21 are both able to bind to IL-4R and IL-21R complexes in an interchangeable manner. CONCLUSIONS: The function of the IL-21R : IL-4R system seems not to be related to the aetiology of CVID in paediatric patients and might be suitable for a regenerative therapy.