Both allergen-specific CD4 and CD8 Type 2 T cells decreased in asthmatic children with immunotherapy

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)-β1 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.

Correlation of cutaneous sensitivity and cytokine response in children with asthma

BACKGROUND

Food allergy occurs in a significant portion of pediatric asthma. Various cells and their mediators/cytokines play a pivotal role in orchestrating the airway inflammatory response in asthma.

OBJECTIVE

To study the cutaneous hypersensitivity, Th1, Th2, and Th17 response of pediatric population with asthma and genetic predisposition to atopy, by determining total immunoglobulin E (IgE) level in response to various food allergens.

MATERIALS AND METHODS

Fifty asthmatic children with a history of worsening symptoms by various food allergens (study group) and twenty healthy children (control group) were included. Food allergy was assessed through skin prick test (SPT) of various food allergens. Total serum IgE level was measured by sandwich ELISA, and T-cell (Th1, Th2, and Th17)-dependent cytokines were measured by flow cytometry.

RESULTS

All 50 asthmatic children in the study group showed SPT positivity against various food allergens (rice = 17; banana, fish and groundnut = 10; wheat = 9; milk and orange = 7; egg = 6; and mango = 4). The average total IgE level in the study group was 316.8 ± 189.8 IU/mL. A significant positive correlation of total IgE with interleukin 17 (IL-17) (r = 0.796; P < 0.0001), IL-13 (r = 0.383; P = 0.01), and IL-4 (r = 0.263; P = 0.043) level was noted. A significant negative correlation of total IgE was noted with interferon gamma (r = -0.5823; P < 0.0001) and IL-10 (r = -0.4474; P < 0.001) level and the duration of breastfeeding (r = -0.31, P = 0.03).

CONCLUSIONS

The present study found a positive correlation between total serum IgE level and Th2, Th17 cytokines in a pediatric population with asthma. A significant negative correlation was found between the duration of breastfeeding and the cytokines.

Therapeutic vaccines for allergic disease

Allergic diseases are highly prevalent worldwide and affect all age groups, contributing to a high personal and socioeconomic burden. Treatment with an “allergy vaccine” or allergen immunotherapy aims to provide long-lasting benefits by inducing unresponsiveness to the relevant antigen. The consequences of the therapy are considered disease modifying and range from dampening of the immediate immune responses to the reduction of secondary tissue remodeling. Furthermore, allergen immunotherapy interventions have a potential to slow or cease the development of additional allergic manifestations with a long-term overall effect on morbidity and quality of life. Here, we review proposed mechanisms underlying the therapeutic effects of immunotherapy for allergic diseases. Further, we discuss both standard and novel approaches and possible future directions in the development of allergen immunotherapy.

Cytokine production by peripheral blood CD4+ and CD8+ T cells in atopic childhood asthma

There are conflicting studies on T cell cytokine production in childhood asthma. In this study intracellular cytokine expression of IL-2, IL-4, IL-10, IL-13, IFN-γ, and TNF-α in CD4⁺ and CD8⁺ T cells in children with atopic asthma were measured by flow cytometry. Results. A significant increase in the percentage of CD4⁺ and CD8⁺ T cells producing IL-4 and IL-13 and decrease in the percentage of CD4⁺ producing IFN-γ in asthmatic children was found. The percentage of CD4⁺/IL-13⁺ was significantly higher in severe asthma than in children with intermittent disease symptoms. Severity of asthma was associated with increased both serum IgE and frequencies of CD4⁺/IL-13⁺ T cells, as well as duration of disease. Moreover, a decrease in FEV₁, FEV₁/FVC was observed in relation to the severity of asthma. Changes in cytokine profile in CD8⁺ subpopulation didn't depend on the severity of the disease. Conclusions. Increased production of IL-4 and IL-13 in both CD4⁺ and CD8⁺ T cells accompanied by decreased IFN-γ expression in CD4⁺ T cells may be evidence that both lymphocyte subpopulations are implicated in the pathogenesis of asthma. Relationship of CD4⁺/IL-13⁺ T cells with disease activity suggests that this lymphocyte subset may have a prominent role in childhood asthma.

Ultra-short course immunotherapy in children and adolescents during a 3-yrs post-marketing surveillance study

Ultra-short course immunotherapy (uSCIT) has shown good efficacy and tolerability in children and adolescents with seasonal allergic rhinitis (SAR), conjunctivitis and/or asthma in clinical studies. Here, we investigate the efficacy of uSCIT in the juvenile subpopulation of a 3-year post-marketing surveillance (PMS) study. To assess the differences in the efficacy of uSCIT between adults and children respectively adolescents enrolled in a PMS study. In a prospective open study 422 patients aged 6-18 years with SAR, conjunctivitis and/or asthma received four pre-seasonal injections with pollen allergoids formulated with monophosphoryl lipid A (MPL, Pollinex Quattro) over a minimum of 3 weeks. Efficacy was evaluated by response to therapy and consumption of anti-allergic medication during the pollen season. Tolerability was evaluated by patients' acceptance of therapy. These results were compared with the adult subpopulation of this study. Response to treatment was assessed as good or very good in 94% of patients, mirroring findings for the entire cohort. Further improvements were noted in patients receiving subsequent courses of therapy. Anti-allergic medication use decreased from 83% to 24% of patients after the first treatment course (p < 0.0001). Therapy was well accepted by children/adolescents and considered 'very good' or 'good' by 93% of juveniles. No serious adverse events or cases of anaphylaxis were reported. This subanalysis indicated that uSCIT with Pollinex Quattro had similar efficacy and tolerability in children/adolescents and adults. The convenient dosing regimen and favourable safety profile of uSCIT may support a wider uptake of uSCIT in this patient population.

Phase I dose-escalation study of a monovalent heat shock protein 70-herpes simplex virus type 2 (HSV-2) peptide-based vaccine designed to prime or boost CD8 T-cell responses in HSV-naïve and HSV-2-infected subjects

This was a phase I study to assess the safety, tolerability, and immunogenicity of escalating doses of AG-702, a noncovalent complex of an HLA A*0201-restricted epitope in the glycoprotein B protein of herpes simplex virus type 2 (gB2) and truncated human constitutive heat shock protein 70. Similar vaccines have been immunogenic in animals. Three injections of 10 to 250 mug were administered intradermally to HLA A*0201-bearing subjects who were either herpes simplex virus type 2 (HSV-2)-infected or HSV uninfected. Sixty-two participants received the vaccine, 60 completed the protocol, and T-cell data were accrued for 56 subjects. The vaccine was safe and well tolerated. New or boosted responses to the HSV-2 CD8 epitope were not detected. Baseline responses to an epitope in virion proteins 13/14 were higher than responses to the gB2 epitope. A heat shock protein vaccine with an HSV-2 peptide appears to be safe at the doses studied in healthy adults with or without HSV infection. Modifications of the dose, adjuvant, route, schedule, or HSV antigen may be required to improve responses.

Allergen immunotherapy in intermittent allergic rhinitis reduces the intracellular expression of IL-4 by CD8+ T cells

BACKGROUND

T helper subset dysregulation is evident in allergic disorders. The role of T cytotoxic subsets is less understood. We investigated whether allergen immunotherapy in intermittent allergic rhinitis influences the intracellular expression of IL-4 and IFN-gamma by CD3+CD8(-) and CD3+CD8+ cells.

METHODS

Nineteen adult patients with intermittent allergic rhinitis were evaluated before the pollen season, and then after one preseasonal course of subcutaneous allergen immunotherapy. Twelve healthy nonatopic patients matched for age and sex served as controls. Intracellular expression of IFN-gamma and IL-4 by CD3+CD8(-) (Th1 and Th2, respectively) and CD3+CD8+ (Tc1 and Tc2, respectively) was estimated by flow cytometry in peripheral blood cells after stimulation with PMA and ionomycin.

RESULTS

Before immunotherapy the percentages of Th1, Th2, Tc1 and Tc2 did not significantly differ between the patients and the controls. After immunotherapy the percentage of Tc2 was lower in the rhinitic patients than in the controls (0.38% vs. 0.45%, p=0.04). The percentage of Tc2 cells decreased significantly after immunotherapy in the intermittent allergic rhinitis group (0.64% vs. 0.38%, p=0.02) with tendency to decrease in ratios of Tc2/Tc1 (p=0.059) and with no changes in ratios of Th2/Th1. The percentages of Th1, Th2 and Tc1 were comparable before and after immunotherapy within the rhinitic patient group.

CONCLUSIONS

The preseasonal allergen subcutaneous immunotherapy applied to intermittent allergic rhinitis patients suppressed the percentage of IL-4 producing CD3+CD8+ cells. Decreased number of CD3+CD8+IL-4+ cells may participate in the regulatory mechanisms of immunotherapy.

The effects of grass pollen allergoid immunotherapy on clinical and immunological parameters in children with allergic rhinitis

Allergoid immunotherapy is a new form of allergen immunotherapy allowing safe administration of high allergen doses. There is limited information on the effects of allergoid immunotherapy in children with allergic rhinitis. To investigate the immunological and clinical effects of allergoid immunotherapy in children with allergic rhinitis due to grass pollen allergy. Children with allergic rhinitis were assigned to allergoid immunotherapy (n = 27) or control (n = 26, no immunotherapy) groups. Children in the immunotherapy group received seven injections of grass pollen allergoid immunotherapy before grass pollen season and continued to receive maintenance immunotherapy for 27 months. All patients were offered a pharmacotherapy regimen to be used on demand during the pollen seasons. Clinical and laboratory parameters were compared between the immunotherapy and control groups. The rhinoconjunctivitis symptom-medication score and asthma symptom score were lower in the immunotherapy group after 1 yr of maintenance immunotherapy (p < 0.01 for both). Skin test reactivity and nasal reactivity as determined by nasal provocation testing for grass pollen were significantly decreased after 1 yr of immunotherapy (p < 0.001 for both). The seasonal increase in bronchial reactivity and nasal lavage eosinophil cationic protein levels were prevented after the first year of immunotherapy (p < 0.05 for both). The seasonal increase in immunoglobulin (Ig)E decreased (p < 0.05) and grass-specific IgG, IgG(1) and IgG(4) increased significantly already at the end of the seven-injection build-up therapy (p < 0.001, for all). Interleukin (IL)-4 levels in the culture supernatants showed a steady decline from baseline at first and second year of immunotherapy (p < 0.001) but remained unchanged in the control group. Allergoid immunotherapy is an effective method in the treatment of grass pollen-induced allergic rhinitis in children and prevents the seasonal increase in bronchial hyper-reactivity. Changes in specific IgE and IgG levels and decreased IL-4 production in peripheral blood mononuclear cell culture supernatants may account for the observed clinical effects.

Targeting memory Th2 cells for the treatment of allergic asthma

Th2 memory cells play an important role in the pathogenesis of allergic asthma. Evidence from patients and experimental models indicates that memory Th2 cells reside in the lungs during disease remission and, upon allergen exposure, become activated effectors involved in disease exacerbation. The inhibition of memory Th2 cells or their effector functions in allergic asthma influence disease progression, suggesting their importance as therapeutic targets. They are allergen specific and can potentially be suppressed or eliminated using this specificity. They have distinct activation, differentiation, cell surface phenotype, migration capacity, and effector functions that can be targeted singularly or in combination. Furthermore, memory Th2 cells residing in the lungs can be treated locally. Capitalizing on these unique attributes is important for drug development for allergic asthma. The aim of this review is to present an overview of therapeutic strategies targeting Th2 memory cells in allergic asthma, emphasizing Th2 generation, differentiation, activation, migration, effector function, and survival.

T regulatory-1 cells induce IgG4 production by B cells: role of IL-10

The study was aimed to find out whether T cells with a regulatory profile could regulate the secretion of IgG4. Using tetanus Ag we found that PBMC of healthy human donors responded to exogenous IL-10 by down-regulating IgG1 and increasing IgG4 secretion. IgE was not affected. To investigate the direct effect of IL-10-producing T cells on B cells, we generated T cell clones (TCC) with two different cytokine profiles: first, IL-10high, IL-2low, IL-4low TCC, and second, IL-10low, IL-2high, IL-4high. The T cell-dependent Ab secretion was measured by coculturing purified CD19+ B cells and the TCC. Interestingly, we found that IgG4 production in the coculture correlated with the TCC production of IL-10 (r2 = 0.352, p = 0.0001), but not with IL-2, IL-4, nor IFN-gamma. IgE showed only a trend with regard to IL-4. Further, there was decreased Ab secretion in the absence of T-B cell contact. IL-10 also induced IgG4 when added to a Th1 TCC-B cell coculture system. The present study thus shows that in T-B cell coculture, IL-10, if induced by the TCC or added to the system, down-regulates the immune response by inducing IgG4 secretion. This establishes a direct implication of IL-10 in humoral hyporesponsiveness, particularly in compartments where the T-B cell interplay determines the subsequent immune response. The correlation between IgG4 and IL-10 (r2 = 0.352) indicates that IL-10 is an important but not the only factor for IgG4 induction.

Induction of T 'regulatory' cells by standardized house dust mite immunotherapy: an increase in CD4+ CD25+ interleukin-10+ T cells expressing peripheral tissue trafficking markers

BACKGROUND

Clinically effective subcutaneous allergen-specific immunotherapy (SIT) is associated with altered circulating T cell cytokine production and altered local cytokine responses with increased IL-10 following allergen challenge in target organs.

OBJECTIVE

This study aimed to elucidate mechanisms for these T cell changes, by examining surface expression of markers for peripheral tissue trafficking on circulating cytokine-positive T cells following standardized house dust mite- (HDM-) SIT.

METHODS

A randomized conventional HDM immunotherapy study was performed on a panel of 12 HDM-allergic subjects. Nine subjects received treatment with conventional HDM immunotherapy using a standardized extract and three subjects were treated by standard pharmacotherapy alone. Symptom and medication scores and allergen-induced cutaneous late-phase responses were assessed before and 9 months after institution of therapy. Before and at 3 and 9 months of SIT, peripheral blood mononuclear cells were cultured for 14 days with HDM extract and CD4+ and CD8+ T cell expression of CD62L, CD49d and CCR5 and production of IL-10, IFN-gamma and IL-4 were analysed by flow cytometry. Allergen-specific T cell proliferation was assessed by 3H-thymidine incorporation.

RESULTS

At 9 months, all SIT-treated patients showed reduced symptom scores and late-phase cutaneous responses to HDM compared with baseline levels. The proportions of CD4+ T cells which were IL-10+ were increased (P < 0.01), and the proportions of CD4+ and CD8+ T cells which were IL-4+ decreased (P < 0.05) compared with baseline. CD4+ and CD8+ T cell IFN-gamma production, expression of surface markers for peripheral tissue trafficking and allergen-specific proliferation remained unchanged during SIT treatment. However, increased proportions of CD4+CD62L(-), CD4+CD49d(hi), CD4+CCR5+ T cells expressing IL-10 were detected at 9 months of SIT compared with baseline (P < 0.05). IL-10 staining co-localized with CD4+CD25+ T cells.

CONCLUSION

Clinically effective subcutaneous immunotherapy with a standardized HDM Dermatophagoides pteronyssinus preparation results in decreased numbers of IL-4+ T cells and expansion of CD4+IL-10+ T cells expressing a peripheral tissue trafficking phenotype. The co-localization of IL-10+ staining to CD4+CD25+ T cells is consistent with the induction of a T regulatory cell population by SIT.

Understanding asthma pathogenesis: linking innate and adaptive immunity

PURPOSE OF REVIEW

Treatment and even prevention of allergic asthma will require a detailed understanding of disease pathogenesis and in particular identification of factors that govern T-helper type 2 (Th2) immunity. This review defines the priming and differentiation steps necessary to develop antiallergen Th2 immunity and highlights recently identified stimuli that satisfy these requirements.

RECENT FINDINGS

Striking discoveries in innate immunity have advanced our understanding of how adaptive immune responses are initiated, yet only recently have these principles been applied to allergic disease. Signaling through certain innate immune receptors, the toll-like receptors (TLR) have been shown to modulate Th2-mediated disease in animal models. The dendritic cell has emerged as the central player in the intricate interplay between the adaptive and innate systems of immunity. Recent studies have also uncovered alternative pathways of initiating allergen sensitization that depend entirely on adaptive, rather than innate immune, triggers.

SUMMARY

The adaptive immune system cannot initiate a response without the "permission" of the innate immune system, and this holds true for Th2 responses to aeroallergens, although induction of Th2 immunity in response to TLR signaling varies with the type and dose of TLR ligand. However, under conditions of ongoing Th2 inflammation, the adaptive immune system can act as its own adjuvant and provide the necessary activating signals to initiate an immune response to foreign protein antigens. This may be the mechanism underlying the clinically observed phenomenon of polysensitization in atopic patients and provides another therapeutic target in asthma.