Suppression function against environmental dust exposure after Dermatophagoides pteronyssinus immunotherapy is associated with production of specific and cross-reactive immunoglobulin G4.

BACKGROUND: Whether Dermatophagoides pteronyssinus (Der-p) allergen immunotherapy (AIT) can induce Dermatophagoides farina (Der-f)-specific immunoglobulin (sIg) G4 production, and tolerance to environmental allergens has not been fully investigated. OBJECTIVE: We aimed to determine serum Der-p-sIgG4 and Der-f-sIgG4 levels in asthma and/or rhinitis patients undergoing Der-p AIT and their ability to reduce immune responses triggered by indoor dust extracts. METHODS: We performed a real-world prospective trial and enrolled patients with allergic rhinitis and/or asthma in Guangzhou, China. These patients received either Der-p AIT (SCIT group) or routine medications (non-SCIT group) for 156 weeks. Clinical outcomes were assessed by the combined symptom medication score (SMS) and FEV1 % changes. House dust samples were collected to analyse allergen levels. Serum levels of Der-p-sIgG4 and Der-f-sIgG4, serum inhibitory capacity against Der-p, Der-f and indoor dust extract by sIgE-facilitated allergen binding to B cells (IgE-FAB), and serum blocking indoor dust extract-induced basophil activation inhibition assays (BATI) in peripheral blood monocytes were carried out at weeks 0, 4, 12, 16, 52, 104 and 156 after the initiations of the treatments. RESULTS: Our study enrolled a total of 60 participants, with 30 patients in each group. Patients in the SCIT group had significantly improved SMS when compared with the baseline and the patients in the non-SCIT group. Median levels of Der-p 1 and Der-f 1 in indoor dust extract were 1.86 µg/g and 4.74 µg/g, respectively. Serum Der-p-sIgG4 and Der-f-IgG4 levels in SCIT patients showed a significant increase from weeks 12 to 156. Serum in these SCIT patients could significantly block Der-p, Der-f and indoor dust extract formation of allergen-sIgE complex and reduced the threshold of IgE-FAB from 16 weeks after the initiation of the treatment. The capacity to inhibit Der-p, Der-f and indoor dust extract BATI was observed in SCIT serum after 12 weeks. Der-p-sIgG4 and Der-f-sIgG4 had a significant correlation with IgE-FAB and BATI in SCIT patients at all time points. CONCLUSION: Single Der-p immunotherapy induced both Der-p-sIgG4 and Der-f-sIgG4 production, which might cross-reactively induce tolerance against environmental allergen exposure in patients with asthma and/or rhinitis.

Blocking function of allergen-specific immunoglobulin G, F(ab')2, and Fab antibodies prepared from patients undergoing Dermatophagoides pteronyssinus immunotherapy.

BACKGROUND: The blocking function of allergen-specific F(ab')2 [sF(ab')2] and Fab (sFab) fragment antibodies prepared from allergen immunotherapy-induced specific immunoglobulin G (sIgG) has not been fully investigated. OBJECTIVE: To investigate the inhibitory function of sIgG, sF(ab')2, and sFab antibodies in patients undergoing Dermatophagoides pteronyssinus (Der-p) subcutaneous immunotherapy (SCIT). METHODS: This study involved 10 subjects (aged 18-42 years) with house dust mite allergic rhinitis or asthma who received a 156-week course of Der-p SCIT. Total IgG levels were purified from the serum of the participants at weeks 0 and 156 by protein A affinity chromatography. Der-p sIgG was purified by affinity chromatography with Der-p as a ligand at week 156. The sF(ab')2 and sFab antibodies were prepared from Der-p sIgG by treatment with pepsin and papain, respectively. Furthermore, IgE-facilitated allergen binding assay, basophil activation inhibition test, and cytokine release inhibition assay were used to assess the inhibitory function of Der-p sIgG, sF(ab')2, and sFab antibodies. RESULTS: We found that the Der-p sIgG, sF(ab')2, and sFab antibodies markedly blocked Der-p-allergen sIgE complex binding to B cells, inhibited basophil activation, and markedly reduced the production of interleukin (IL)-5, IL-13, IL-17, and tumor necrosis factor-α by peripheral blood mononuclear cells. CONCLUSION: SCIT-induced Der-p sIgG, sF(ab')2, and sFab antibodies may block the formation of Der-p-sIgE complexes and may serve as a potential allergen-targeted biologics candidate for the treatment of allergic asthma. CLINICAL TRIAL REGISTRATION: This study was approved by the Ethics Committee of the First Affiliated Hospital of Guangzhou Medical University and registered in the Chinese Clinical Trial Registry (ChiCTR-OOC-15006207, https://www.chictr.org.cn/enindex.aspx).

Changes in CD4+CD25+FoxP3+ Regulatory T Cells and Serum Cytokines in Sublingual and Subcutaneous Immunotherapy in Allergic Rhinitis with or without Asthma.

BACKGROUND: Few studies have directly compared the immunologic responses to specific subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). OBJECTIVE: We aimed to directly compare clinical efficacy and immunological responses between SLIT and SCIT in allergic rhinitis (AR) sensitized to house dust mites. METHODS: Sixty-seven patients (age 5-55 years) with moderate-severe Dermatophagoides pteronyssinus (Der-p) and Dermatophagoides farinae AR with or without asthma were randomized (2:2:1) into SLIT (n = 27), SCIT (n = 26) and placebo (n = 14) groups. Symptom and medication scores, visual analogue score, serum Der-p specific immunoglobulin G4 (Der-p-sIgG4), CD4+CD25+FoxP3+ regulatory T cells (Tregs) and serum cytokines were measured. RESULTS: After 1-year treatment, a significant improvement of total rhinitis score (TRS), total rhinitis medication score (TRMS) and visual analogue score occurred in both SLIT and SCIT. There were no differences in clinical efficacy except for TRMS (p = 0.026) when SLIT and SCIT were directly compared. CD4+CD25+FoxP3+ Tregs had a trend towards upregulation in the 2 modes and inversely correlated with TRS (p = 0.024) only in SLIT. Der-p-sIgG4 significantly increased in SLIT and SCIT (p < 0.05), and it was 30 times higher in SCIT than SLIT after the treatment (p < 0.05). Serum interferon-γ significantly increased only in SCIT after 1 (p = 0.008), 6 (p = 0.007) and 12 (p = 0.008) months of treatment and inversely correlated with TRS (p = 0.032). CONCLUSION: While SCIT and SLIT have similar rates of clinical improvement, the 2 modes reveal heterogeneous changes of CD4+CD25+Foxp3+ Tregs, sIgG4 and cytokines.

Functional and Immunoreactive Levels of IgG4 Correlate with Clinical Responses during the Maintenance Phase of House Dust Mite Immunotherapy.

Allergen-specific immunotherapy for house dust mite allergy is effective, but there are no validated biomarkers reflecting or predicting the clinical efficacy. We aimed to investigate the relationship between clinical outcomes and functional responses of allergen-specific IgG4 (sIgG4) and specific IgE (sIgE) during Dermatophagoides pteronyssinus s.c. allergen immunotherapy (SCIT) in allergic rhinitis and/or asthma patients. Combined symptom medication scores (SMS), D. pteronyssinus-sIgG4 levels, D. pteronyssinus-sIgE levels, and the serum inhibitory capacity against D. pteronyssinus-sIgE facilitated allergen binding to B cells (IgE-FAB) were determined during the updosing (week 0, 4, 12, and 16) and maintenance (week 52, 104, and 156) phase of SCIT. We found that SCIT patients had a significant improvement in SMS from week 52 to 156 compared with medication-treated control subjects (p < 0.05). Levels of D. pteronyssinus-sIgG4 in SCIT patients showed a significant increase from week 12 to 156 (p < 0.05). Serum obtained from SCIT patients significantly inhibited D. pteronyssinus-sIgE binding to B cells after 16 wk (p < 0.01). Significantly lower levels of D. pteronyssinus-sIgE were observed in SCIT patients after 52 wk (p < 0.05). A significant relationship was demonstrated between SMS and IgE-FAB or D. pteronyssinus-sIgG4 during the maintenance phase according to linear regression analysis. In conclusion, D. pteronyssinus-sIgG4 level and D. pteronyssinus IgE-FAB are associated with clinical efficacy in the maintenance phase rather than the updosing phase of SCIT. Immunologic tolerance can be induced with SCIT when maintenance phase is achieved.

Specific immunoglobulin G4 correlates with Th2 cytokine reduction in patients with allergic asthma treated by Dermatophagoides pteronyssinus subcutaneous immunotherapy.

Background: The modulations of lymphocyte subsets and cytokine production due to subcutaneous allergen immunotherapy (SCIT) are not fully clarified. Objective: We investigated the changes in T-lymphocyte subsets and serum Dermatophagoides pteronyssinus-specific immunoglobulin G4 (Der-p sIgG4), as well as cytokine production during Der-p SCIT, in patients with allergic asthma. Methods: This study involved 20 patients with allergic asthma who were receiving 156-week Der-p SCIT and 20 patients without SCIT (non-SCIT). We measured symptom and medication scores (SMS), serum Der-p sIgG4 levels, CD4+CD25+Foxp3+ T regulatory (Treg), CD4+IL-4-IFN-γ+ T-helper (Th) 1, and CD4+IL-4+IFN-γ- Th2 lymphocyte percentages in peripheral blood mononuclear cells (PBMCs) with/without Der-p extract stimulation at weeks 0, 4, 12, 16, 52, 104, and 156. Cytokine release inhibition assays were performed by incubation with serum from SCIT and non-SCIT patients, Der-p allergen, and PBMCs. Levels of interleukin (IL)-4, IL-5, IL-10, IL-13, IL-17, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-ß1 were evaluated in supernatant. Results: We found that SCIT patients had significantly lower SMS after week 52. Der-p sIgG4 levels in SCIT patients significantly increased at week 16 compared with non-SCIT subjects. CD4+IL-4+IFN-γ- Th2% in SCIT patients showed a significant decrease from weeks 104-156 compared with week 0, while no change was observed in CD4+CD25+Foxp3+ Treg and CD4+IL-4-IFN-γ+ Th1 percentages. IL-5, IL-13, IL-4, IL-17, and TNF-α levels in supernatant of PBMCs cultured with serum of SCIT patients after 16 weeks showed significant lower levels compared with non-SCIT patients, and showed significant reverse associations with Der-p sIgG4 levels. Conclusion: SCIT induced Dep-p sIgG4 may be involved in downregulating Th2 cytokine production in Der-p allergic asthma patients.

Allergen Immunotherapy-Induced Immunoglobulin G4 Reduces Basophil Activation in House Dust Mite-Allergic Asthma Patients.

It is unclear if allergen immunotherapy (AIT) can reduce allergy effector cell activation. We evaluated the basophil response during Dermatophagoides pteronyssinus (Der p) subcutaneous immunotherapy (SCIT) and its relationship to allergen-specific immunoglobulin G4 (sIgG4) in allergic rhinitis and/or asthma patients. The study included 55 subjects, of which 35 cases received Der p SCIT and 20 controls received standard medications. Symptom and medication scores (SMSs), sIgG4 levels, specific immunoglobulin E (sIgE) levels, allergen-induced basophil activation tests (BATs) in whole blood, and BAT inhibition assays in serum were determined at weeks 0, 4, 12, 16, 52, and 104 of SCIT. Levels of Der p sIgG4 in SCIT patients significantly increased after 12 weeks of treatment compared to week 0. Serum obtained from SCIT patients significantly inhibited basophil activation after 12 weeks of treatment. Removal of immunoglobulin G4 (IgG4) antibodies at week 104 reduced the ability of serum to block basophil activation. An increase of Der p sIgG4 rather than reduction of Der p sIgE correlated with the reduction of basophil activation during SCIT. The sIgG4 antibodies may compete with sIgE binding to allergens to form an immunoglobulin E (IgE)-allergen complex. SCIT reduced the sensitivity of allergen-triggered basophil activation in Der p allergic rhinitis and/or asthma patients through induction of sIgG4.