Differences in allergen-specific basophil activation and T cell proliferation in atopic dermatitis patients with comorbid allergic rhinoconjunctivitis treated with a monoclonal anti-IL-4Rα antibody or allergen-specific immunotherapy

BACKGROUND

Atopic dermatitis (AD), a chronic inflammatory disorder, is often accompanied by allergic rhinoconjunctivitis (ARC) as a co-morbidity. The use of a monoclonal anti-IL-4Rα antibody has been effective in controlling moderate to severe AD symptoms. Allergen-specific immunotherapy (AIT) is widely used for the treatment of ARC and asthma. The effects of AIT on basophil reactivity/effector functions have already been examined and used as indicators of the treatment efficacy. However, it is unclear, how an anti-IL-4Rα antibody can influence allergen-specific immune responses of basophils and T cells of AD patients with comorbid ARC.

OBJECTIVE

To investigate the effect of a monoclonal anti-IL-4Rα antibody on the in vitro allergic responses of basophils and T cells deriving from AD patients with comorbid ARC.

METHODS

Blood samples of 32 AD patients were obtained before, after 4 and 16 weeks of an anti-IL-4Rα antibody therapy (300 mg subcutaneously/2 weeks; n = 21) or AIT (daily sublingual application; n = 11). Patients treated with an anti-IL-4Rα antibody were grouped according to their serum specific immunoglobulin E levels and ARC symptoms, while patients receiving an AIT were additionally grouped according to the allergen specificity of their AIT. Basophil activation test and T cell proliferation assays were undertaken after an in vitro allergen stimulation.

RESULTS

A significant reduction of the immunoglobulin E levels and the allergen-specific T cell proliferation was observed in AD patients treated with an anti-IL-4Rα -antibody, while the allergen-specific basophil activation/sensitivity were found to be significantly increased. In patients receiving an AIT, the in vitro allergen-specific basophil activation and the T cell proliferation were found to be significantly decreased in response to seasonal allergens.

CONCLUSIONS

An IL-4Rα blockade induced by a monoclonal anti-IL-4Rα antibody leads to an increased activity/sensitivity of early effector cells (such as basophils), in contrast to a decreasing reactivity observed under an AIT. The late-phase T cell reaction to allergens did not differ between the herein assessed treatments.

In vitro Conversion into CD4+CD25+Foxp3+ Induced Regulatory T Cells Is Reduced in Atopic Dermatitis Patients

BACKGROUND

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases, with an increasing incidence in clinical practice. AD models have demonstrated that TGF-β signaling is compromised in regulatory T cells (Tregs).

OBJECTIVES

This study aimed to investigate the TGF-β-dependent in vitro conversion of CD4+CD25- T cells derived from AD-patients into CD4+CD25+Foxp3+ induced Tregs (iTregs) in comparison to healthy controls.

METHODS

To analyze in vitro iTreg conversion, human CD4+CD25- T cells were cultured on anti-CD3-coated plates in the presence of TGF-β and IL-2 for up to 3 days. Consequently, the underlying mechanism of impaired CD4+CD25+Foxp3+ iTreg generation was explored by focusing on TGF-β signaling. Finally, the functionality of iTregs was investigated.

RESULTS

Conversion of CD4+CD25-Foxp3- into CD4+CD25+Foxp3+ iTregs was diminished in AD individuals. Impaired iTreg generation was accompanied by a reduced surface expression of GARP (glycoprotein A repetitions predominant), a marker for activated Tregs. A reduced expression of Smad3 mRNA was revealed in CD4+CD25- T cells. Interestingly, the suppressive quality of iTregs was found to be equal in cells derived from AD and healthy donors.

CONCLUSION

The signaling effect of TGF-β receptors on the suppressor quality of iTreg conversion is conserved. Impaired iTreg generation might be a reason for the lack of immune suppression in AD patients and contributes to the chronicity of the disease.

Role of α-melanocyte stimulating hormone in the induction of regulatory T cells in ocular allergy (HYP7P.318)

Allergic conjunctivitis (AC) is one of the most common eye disorders in ophthalmology. AC is a disorder mediated by Th2 cells, where the eye inflammation is caused by a type I hypersensitivity. It has been suggested that some neuropeptides are increased (CGRP, SP and VIP) in AC contributing to local damage. In other hand, α-MSH plays an immunomodulatory role in ocular tissues; however, its role in ocular allergic disease is unknown, thus it was the aim of this study. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from blood samples of healthy donors (HD) and AC-patients skin reactive to Dermatophagoides pteronyssinus (Der p), then PBMC were cultured with different stimuli: Der p, α-MSH, or Der p plus α-MSH. After 7 days, PBMC were harvested, labeled with mAbs against CD4-PECy5, CD25-PE, FOXP3-FITC and analyzed by flow cytometry. Results. Der p or α-MSH stimulation did not induced significant changes in the frequency of Tregs; interestingly, after α-MSH plus Der p stimulation a significant higher frequency of Tregs cells was observed than Der p alone. Conclusions: Tregs differentiation in patients with AC is dependent of Ag and addition of α-MSH, if α-MSH is involved in local Treg differentiation is not known and needs further investigation.

The ocular surface: from physiology to the ocular allergic diseases

Allergic conjunctivitis (AC) is an inflammation of the conjunctiva secondary to an immune response to exogenous antigens, usually called allergens. In fact, AC is a syndrome that involves the entire ocular surface, including conjunctiva, lids, cornea, and tear film. The signs and symptoms of AC have a meaningful effect on comfort and patient health, and could be influenced by environment, genetics and immune regulation mechanisms, all of which work together in a complex immunological homeostasis. Dysregulation in such immune responses could turn into a variety of ocular allergic diseases (OAD). This review describes some of the current understanding of cellular and molecular pathways involved in different OAD.