The effect of anti-IL5 monoclonal antibodies on regulatory and effector T cells in severe eosinophilic asthma.

INTRODUCTION: Biological treatments have redesigned the clinical management of severe eosinophilic asthmatic (SA) patients. Despite emerging evidence supporting the role of natural Killer (NK), and T regulatory cells (Treg) in the pathogenesis of asthma, no data is available on the effects of anti-IL5/IL5R therapies on these cell subsets. METHODS: We prospectively enrolled fourteen SA patients treated with benralizumab (n = 7) or mepolizumab (n = 7) and compared them with healthy controls (HC) (n = 11) and mild to moderate asthmatic (MM) patients (n = 9). Clinical parameters were collected at baseline (T0) and during follow-up. Cellular analysis, including the analysis of T/NK cell subsets, was determined through multicolor flow cytometry. RESULTS: At T0, SA patients showed higher percentages of CD4 TEM (33.3 ± 17.9 HC, 42.6 ± 16.6 MM and 66.1 ± 19.7 in SA; p < 0.0001) than HC and MM patients. With different timing, the two drugs induce a reduction of CD4 TEM ( 76 ± 19 T0; 43 ± 14 T1; 45 ± 23 T6; 62 ± 18 at T24; p < 0.0001 for mepolizumab and 55 ± 21 T0; 55 ± 22 T1; 43 ± 14 T6; 27 ± 12 at T24; p < 0.0001 for benralizumab) and an increase of Treg cells (1.2 ± 1.3 T0; 5.1 ± 2.5 T1; 6.3 ± 3.4 T6; 8.4 ± 4.6 at T24; p < 0.0001 for mepolizumab and 3.4 ± 1.7 T0; 1.9 ± 0.8 T1; 1.9 ± 1 T6; 5.1 ± 2.4 at T24; p < 0.0001 for benralizumab). The change of CD56dim PD-1+ significantly correlated with FEV1% (r = - 0.32; p < 0.01), while Treg expressing PD-1 correlates with the use of oral steroids ( r = 0.36 p = 0.0008) and ACT score (r = 0.36 p = 0.0008) p < 0.001) CONCLUSIONS: Beyond the clinical improvement, anti-IL-5 treatment induces a rebalancing of Treg and T effector cells in patients with SA.

Benralizumab affects NK cell maturation and proliferation in severe asthmatic patients.

INTRODUCTION: The mechanism of action of benralizumab is determined by its afucosylated constant fragment that binds CD16a receptors on the membrane of natural killer cells. Here we analysed changes in Natural Killer and T-cells in Severe asthmatic patients, before and after benralizumab. METHODS: Natural Killer and T-cell subsets were detected through multiparametric flow cytometry. The concentrations of serum cytokines levels were detected through multiplex assay. Functional proliferation assay was performed in follow-up samples in severe asthmatic patients. RESULTS: At baseline, severe asthmatic patients showed higher percentages of immature Natural Killer cells when compared with healthy controls. We demonstrate the proliferative capacity of these cells and their activation after benralizumab administration. Benralizumab shifted Natural Killer cell phenotypes towards maturity. Correlation between the Natural Killer cells and functional parameters and with steroid-sparing was observed. CONCLUSION: Together this data contributes to our understanding of the mechanisms of action of benralizumab in the resolution of inflammation in severe asthma patients.

Exploring the Interaction between Fractional Exhaled Nitric Oxide and Biologic Treatment in Severe Asthma: A Systematic Review.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is a biomarker of airway inflammation associated with airway hyper-responsiveness and type-2 inflammation. Its role in the management of severe asthmatic patients undergoing biologic treatment, as well as FeNO dynamics during biologic treatment, is largely unexplored. PURPOSE: The aim was to evaluate published data contributing to the following areas: (1) FeNO as a predictive biomarker of response to biologic treatment; (2) the influence of biologic treatment in FeNO values; (3) FeNO as a biomarker for the prediction of exacerbations in patients treated with biologics. METHODS: The systematic search was conducted on the Medline database through the Pubmed search engine, including all studies from 2009 to the present. RESULTS: Higher baseline values of FeNO are associated with better clinical control in patients treated with omalizumab, dupilumab, and tezepelumab. FeNO dynamics during biologic treatment highlights a clear reduction in FeNO values in patients treated with anti-IL4/13 and anti-IL13, as well as in patients treated with tezepelumab. During the treatment, FeNO may help to predict clinical worsening and to differentiate eosinophilic from non-eosinophilic exacerbations. CONCLUSIONS: Higher baseline FeNO levels appear to be associated with a greater benefit in terms of clinical control and reduction of exacerbation rate, while FeNO dynamics during biologic treatment remains a largely unexplored issue since few studies have investigated it as a primary outcome. FeNO remains detectable during biologic treatment, but its potential utility as a biomarker of clinical control is still unclear and represents an interesting research area to be developed.

Follicular T Helper and Breg Cell Balance in Severe Allergic Asthma Before and After Omalizumab Therapy.

BACKGROUND: Severe allergic asthma (SAA) is based on type 2 (T2-high) immune responses to allergens promoting type 2 T helper (Th2) cell cytokine responses and production of IgE antibodies. Omalizumab was the first biological drug licensed for clinical use in the management of IgE-mediated SAA. Despite emerging evidence supporting the prominent role of follicular T cells (Tfh), Breg and Treg subsets, in the development and progression of SAA, no data are available on the impact of omalizumab therapy. METHODS: Ten SAA patients monitored at the Respiratory Diseases Unit of Siena University Hospital and ten healthy sex- and age-matched controls were enrolled in the study. Clinical and functional parameters were collected at baseline (T0) and after 6 months of therapy (T6). Cellular population analysis was determined through multicolour flow cytometry. RESULTS: SAA patients showed higher percentages of Th17.1, Tfh and Tfh2 while CD24hiCD27hi Breg cell, Treg and Tfr percentages were significantly lower than in controls. Higher percentages of Tfh2 in patients with nasal polyps than in those without and in controls were observed. At T6, significant decreases in Tfh and Tfh2 compared with T0 were observed. A slightly significant increase in Teffs was reported at T6 compared to T0. ΔIgE levels in serum were correlated with ΔCD19+CD24+CD27+ Breg cell percentages (r = - 0.86, p = 0.0022). CONCLUSIONS: Our data explored the changes in Tfh cells, Tregs and Bregs in severe asthma. The restoration of immunological imbalance in SAA patients after omalizumab is certainly intriguing and represents a glimpse into the comprehension of immunological effects of treatment.