Innate immune responses to rhinovirus are reduced by the high-affinity IgE receptor in allergic asthmatic children

Abstract

Background: Children with allergic asthma have more frequent and severe human rhinovirus (HRV)-induced wheezing and asthma exacerbations through unclear mechanisms.

Objective: We sought to determine whether increased high-affinity IgE receptor (FcεRI) expression and cross-linking impairs innate immune responses to HRV, particularly in allergic asthmatic children.

Methods: PBMCs were obtained from 44 children, and surface expression of FcεRI on plasmacytoid dendritic cells (pDCs), myeloid dendritic cells, monocytes, and basophils was assessed by using flow cytometry. Cells were also incubated with rabbit anti-human IgE to cross-link FcεRI, followed by stimulation with HRV-16, and IFN-α and IFN-λ1 production was measured by Luminex. The relationships among FcεRI expression and cross-linking, HRV-induced IFN-α and IFN-λ1 production, and childhood allergy and asthma were subsequently analyzed.

Results: FcεRIα expression on pDCs was inversely associated with HRV-induced IFN-α and IFN-λ1 production. Cross-linking FcεRI before HRV stimulation further reduced PBMC IFN-α (47% relative reduction; 95% CI, 32% to 62%; P< .0001) and IFN-λ1 (81% relative reduction; 95% CI, 69% to 93%; P< .0001) secretion. Allergic asthmatic children had higher surface expression of FcεRIα on pDCs and myeloid dendritic cells when compared with that seen in nonallergic nonasthmatic children. Furthermore, after FcεRI cross-linking, allergic asthmatic children had significantly lower HRV-induced IFN responses than allergic nonasthmatic children (IFN-α, P= .004; IFN-λ1, P= .02) and nonallergic nonasthmatic children (IFN-α, P= .002; IFN-λ1, P= .01).

Conclusions: Allergic asthmatic children have impaired innate immune responses to HRV that correlate with increased FcεRI expression on pDCs and are reduced by FcεRI cross-linking. These effects likely increase susceptibility to HRV-induced wheezing and asthma exacerbations.

Figure 1

Figure 1A. Comparison of PBMC HRV-induced mean IFN-α production when pretreated with media (no pretreatment), 1 μg/mL rabbit IgG isotype control Ab or 1 μg/mL anti-IgE for 2 hours. Pretreatment of PBMCs using 1 μg/mL anti-IgE to cross-link FcεRI resulted in significantly lower HRV-induced IFN-α (mean [±SE] 750±108 pg/mL) compared to pretreatment with 1 μg/mL rabbit IgG isotype control (1299±141 pg/mL; p<0.0001) or no pretreatment (1410±150 pg/mL; p<0.0001). N= 44. Figure 1B. Comparison of PBMC HRV-induced mean IFN-λ1 production (pg/mL) when pretreated with media (no pretreatment), 1 μg/mL rabbit IgG isotype control Ab or 1 μg/mL anti-IgE for 2 hours. Pretreatment of PBMCs using 1 μg/mL anti-IgE to cross-link FcεRI resulted in significantly lower HRV-induced IFN-λ1 (mean [±SE] 39±9 pg/mL) compared to pretreatment with 1 μg/mL rabbit IgG isotype control (171±31 pg/mL; p<0.0001) or no pretreatment (206±36 pg/mL; p<0.0001). N = 44.

Figure 1

Figure 1A. Comparison of PBMC HRV-induced mean IFN-α production when pretreated with media (no pretreatment), 1 μg/mL rabbit IgG isotype control Ab or 1 μg/mL anti-IgE for 2 hours. Pretreatment of PBMCs using 1 μg/mL anti-IgE to cross-link FcεRI resulted in significantly lower HRV-induced IFN-α (mean [±SE] 750±108 pg/mL) compared to pretreatment with 1 μg/mL rabbit IgG isotype control (1299±141 pg/mL; p<0.0001) or no pretreatment (1410±150 pg/mL; p<0.0001). N= 44. Figure 1B. Comparison of PBMC HRV-induced mean IFN-λ1 production (pg/mL) when pretreated with media (no pretreatment), 1 μg/mL rabbit IgG isotype control Ab or 1 μg/mL anti-IgE for 2 hours. Pretreatment of PBMCs using 1 μg/mL anti-IgE to cross-link FcεRI resulted in significantly lower HRV-induced IFN-λ1 (mean [±SE] 39±9 pg/mL) compared to pretreatment with 1 μg/mL rabbit IgG isotype control (171±31 pg/mL; p<0.0001) or no pretreatment (206±36 pg/mL; p<0.0001). N = 44.

Figure 2

Figure 2A. Comparison of allergic asthmatic (N = 14), allergic non-asthmatic (N = 13), and non-allergic non-asthmatic (N = 14) children’s PBMC HRV-induced IFN-α production (pg/mL) after cross-linking FcεRI with 1 μg/mL anti-IgE for 2 hours prior to HRV stimulation. Allergic asthmatic children had significantly lower HRV induced IFN-α production (mean [±SE] 366±126 pg/mL) than both allergic non-asthmatics (1085±261 pg/mL; p = 0.004) and non-allergic non-asthmatics (878±159 pg/mL; p=0.002). Figure 2B. Comparison of allergic asthmatic (N = 14), allergic non-asthmatic (N = 13), and non-allergic non-asthmatic (N = 14) children’s PBMC HRV-induced mean IFN-λ1 production (pg/mL) after cross-linking FcεRI with 1 μg/mL anti-IgE for 2 hours prior to HRV stimulation. Allergic asthmatic children had significantly lower HRV-induced IFN-λ1 production (mean [±SE] 16±5 pg/mL) than both allergic non-asthmatics (62±28 pg/mL; p=0.02) and non-allergic non-asthmatics (42±8 pg/mL; p=0.01).

Figure 2

Figure 2A. Comparison of allergic asthmatic (N = 14), allergic non-asthmatic (N = 13), and non-allergic non-asthmatic (N = 14) children’s PBMC HRV-induced IFN-α production (pg/mL) after cross-linking FcεRI with 1 μg/mL anti-IgE for 2 hours prior to HRV stimulation. Allergic asthmatic children had significantly lower HRV induced IFN-α production (mean [±SE] 366±126 pg/mL) than both allergic non-asthmatics (1085±261 pg/mL; p = 0.004) and non-allergic non-asthmatics (878±159 pg/mL; p=0.002). Figure 2B. Comparison of allergic asthmatic (N = 14), allergic non-asthmatic (N = 13), and non-allergic non-asthmatic (N = 14) children’s PBMC HRV-induced mean IFN-λ1 production (pg/mL) after cross-linking FcεRI with 1 μg/mL anti-IgE for 2 hours prior to HRV stimulation. Allergic asthmatic children had significantly lower HRV-induced IFN-λ1 production (mean [±SE] 16±5 pg/mL) than both allergic non-asthmatics (62±28 pg/mL; p=0.02) and non-allergic non-asthmatics (42±8 pg/mL; p=0.01).