The contact sensitizer diphenylcyclopropenone has adjuvant properties in mice and potential application in epicutaneous immunotherapy

The clonal structure and dynamics of the human T cell response to an organic chemical hapten

Diphenylcyclopropenone (DPC) is an organic chemical hapten which induces allergic contact dermatitis and is used in the treatment of warts, melanoma, and alopecia areata. This therapeutic setting therefore provided an opportunity to study T cell receptor (TCR) repertoire changes in response to hapten sensitization in humans. Repeated exposure to DPC induced highly dynamic transient expansions of a polyclonal diverse T cell population. The number of TCRs expanded early after sensitization varies between individuals and predicts the magnitude of the allergic reaction. The expanded TCRs show preferential TCR V and J gene usage and consist of clusters of TCRs with similar sequences, two characteristic features of antigen-driven responses. The expanded TCRs share subtle sequence motifs that can be captured using a dynamic Bayesian network. These observations suggest the response to DPC is mediated by a polyclonal population of T cells recognizing a small number of dominant antigens.

Alternative products to treat allergic rhinitis and alternative routes for allergy immunotherapy

BACKGROUND

Some alternative products instead of immunotherapy are used in patients with allergic rhinitis (AR).

METHODS

In this paper, alternative products to treat allergic rhinitis and alternative routes for allergy immunotherapy are reviewed.

RESULTS

Alternative products and methods used instead of immunotherapy are tea therapy, acupuncture, Nigella sativa, cinnamon bark, Spanish needle, acerola, capsaicin (Capsicum annum), allergen-absorbing ointment, and cellulose powder. N. sativa has been used in AR treatment due to its anti-inflammatory effects. N. sativa oil also inhibits the cyclooxygenase and 5-lipoxygenase pathways of arachidonic acid metabolism. The beneficial effects of N. sativa seed supplementation on the symptoms of AR may be due to its antihistaminic properties. To improve the efficacy of immunotherapy, some measures are taken regarding known immunotherapy applications and alternative routes of intralymphatic immunotherapy and epicutaneous immunotherapy are used.

CONCLUSION

There are alternative routes and products to improve the efficacy of immunotherapy.

Cutaneous vaccination with coated microneedles prevents development of airway allergy

Allergy cases are increasing worldwide. Currently allergies are treated after their appearance in patients. However, now there is effort to make a preventive vaccine against allergies. The rationale is to target patient populations that are already sensitized to allergens but have yet to develop severe forms of the allergic disease, or who are susceptible to allergy development but have not yet developed them. Subcutaneous injections and the sublingual route have been used as the primary mode of preventive vaccine delivery. However, injections are painful, especially considering that they have to be given repeatedly to infants or young children. The sublingual route is hard to use since infants can't be trained to hold the vaccine under their tongue. In the present study, we demonstrate a microneedle (MN)-based cutaneous preventive allergy treatment against ovalbumin (Ova)-induced airway allergy in mice. Insertion of MNs coated with Ova as a model allergen and CpG oligonucleotide as an adjuvant (MNs-CIT) into the skin significantly induced Ova specific systemic immune response. This response was similar to that induced by hypodermic-needle-based delivery of Ova using the clinically-approved subcutaneous immunotherapy (SCIT) route. MNs-CIT regulated Th2 cytokines (IL-4, IL-5 & IL-13) and anti-inflammatory cytokines (IL-10) in the bronchoalveolar fluid, and IL-2 and IFN-γ cytokines in restimulated splenocyte cultures. Absence of mucus deposition inside the bronchiole wall and low collagen around the lung bronchioles after Ova-allergen challenge further confirmed the protective role of MNs-CIT. Overall, MNs-CIT represents a novel minimally invasive cutaneous immunotherapy to prevent the progression of Ova induced airway allergy in mice.

Novel Delivery Routes for Allergy Immunotherapy: Intralymphatic, Epicutaneous, and Intradermal

Current allergy immunotherapy protocols suffer from two main problems: long treatment duration and systemic allergic side effects of the allergen administrations. The immunologic effects of allergen administration could be enhanced and the number of allergen administrations and treatment duration reduced by choosing a tissue for administration that contains a high density of antigen-presenting cells. Local side effects could be reduced by choosing a route characterized by a low density of mast cells, and systemic side effects could be reduced by administration to nonvascularized tissues, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized.

Determinants of efficacy and safety in epicutaneous allergen immunotherapy: summary of three clinical trials

The results of our third trial on epicutaneous allergen-specific immunotherapy (EPIT) will be presented and discussed in the context of our previous trials. This monocentric, placebo-controlled, double-blind phase I/IIa trial included 98 patients with grass pollen rhinoconjunctivitis. Prior to the pollen season 2009, patients received six patches (allergen extract: n = 48; placebo: n = 50) with weekly intervals, administered onto tape-stripped skin. Allergen EPIT produced a median symptom improvement of 48% in 2009 and 40% in the treatment-free follow-up year 2010 as compared to 10% and 15% improvement after placebo EPIT (P = 0.003). After allergen EPIT but not placebo EPIT, conjunctival allergen reactivity was significantly decreased and allergen-specific IgG4 responses were significantly elevated (P < 0.001). In conclusion, our three EPIT trials found that allergen EPIT can ameliorate hay fever symptoms. Overall, treatment efficacy appears to be determined by the allergen dose. Local side-effects are determined by the duration of patch administration, while risk of systemic allergic side-effects is related to the degree of stratum corneum disruption.

Is The Allergen Really Needed in Allergy Immunotherapy?

Immunotherapy for type I allergies is well established and is regarded to be the most efficient treatment option besides allergen avoidance. As of today, different forms of allergen preparations are used in this regard, as well as different routes of application. Virus-like particles (VLPs) represent a potent vaccine platform with proven immunogenicity and clinical efficacy. The addition of toll-like receptor ligands and/or depot-forming adjuvants further enhances activation of innate as well as adaptive immune responses. CpG motifs represent intensively investigated and potent direct stimulators of plasmacytoid dendritic cells and B cells, while T cell responses are enhanced indirectly through increased antigen presentation and cytokine release. This article will focus on the function of VLPs loaded with DNA rich in nonmethylated CG motifs (CpGs) and the clinical experience gained in the treatment of allergic rhinitis, demonstrating clinical efficacy also if administered without allergens. Several published studies have demonstrated a beneficial impact on allergic symptoms by treatment with CpG-loaded VLPs. Subcutaneous injection of VLPs loaded with CpGs was tested with or without the adjuvant alum in the presence or absence of an allergen. The results encourage further investigation of VLPs and CpG motifs in immunotherapy, either as a stand-alone product or as adjuvants for allergen-specific immunotherapy.

Oxazolone-induced contact hypersensitivity reduces lymphatic drainage but enhances the induction of adaptive immunity

Contact hypersensitivity (CHS) induced by topical application of haptens is a commonly used model to study dermal inflammatory responses in mice. Several recent studies have indicated that CHS-induced skin inflammation triggers lymphangiogenesis but may negatively impact the immune-function of lymphatic vessels, namely fluid drainage and dendritic cell (DC) migration to draining lymph nodes (dLNs). On the other hand, haptens have been shown to exert immune-stimulatory activity by inducing DC maturation. In this study we investigated how the presence of pre-established CHS-induced skin inflammation affects the induction of adaptive immunity in dLNs. Using a mouse model of oxazolone-induced skin inflammation we observed that lymphatic drainage was reduced and DC migration from skin to dLNs was partially compromised. At the same time, a significantly stronger adaptive immune response towards ovalbumin (OVA) was induced when immunization had occurred in CHS-inflamed skin as compared to uninflamed control skin. In fact, immunization with sterile OVA in CHS-inflamed skin evoked a delayed-type hypersensitivity (DTH) response comparable to the one induced by conventional immunization with OVA and adjuvant in uninflamed skin. Striking phenotypic and functional differences were observed when comparing DCs from LNs draining uninflamed or CHS-inflamed skin. DCs from LNs draining CHS-inflamed skin expressed higher levels of co-stimulatory molecules and MHC molecules, produced higher levels of the interleukin-12/23 p40 subunit (IL-12/23-p40) and more potently induced T cell activation in vitro. Immunization experiments revealed that blockade of IL-12/23-p40 during the priming phase partially reverted the CHS-induced enhancement of the adaptive immune response. Collectively, our findings indicate that CHS-induced skin inflammation generates an overall immune-stimulatory milieu, which outweighs the potentially suppressive effect of reduced lymphatic vessel function.

Molecular characterization of human skin response to diphencyprone at peak and resolution phases: therapeutic insights

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. It is used as an immune modulating therapeutic, but its molecular effects in human skin are largely unknown. We studied cellular and molecular characteristics of a recall response to 0.04% DPCP at 3 day (peak) and 14 day (resolution) timepoints using immune markers, RT-PCR and gene array approaches. A peak response showed modulation of ~7,500 mRNA transcripts, with high expression of cytokines that define all major effector T-cell subsets. Concomitant increases in T-cell and CD11c+ dendritic cell (DC) infiltrates were measured. The resolution reaction was characterized by unexpectedly high levels of T-cells and mature (DC-LAMP+) DCs, but with marked decreases in expression of IL-2, IFNγ, and other T-cell derived cytokines. However, negative immune regulators such as IDO1 that were high in peak reactions, continued to have high expression in resolution reactions. In the resolution reaction, ~1,500 mRNA transcripts were significantly different from placebo-treated skin. These data suggest the response to DPCP evolves from an inflammatory/effector peak at day 3 to a more regulated immune response after 14 days. This model system could be useful for further dissection of mechanisms of immune activation or negative immune regulation in human skin.

Epicutaneous immune modulation with Bet v 1 plus R848 suppresses allergic asthma in a murine model

BACKGROUND

Combining allergen(s) with an adjuvant is a strategy to improve the efficacy and safety of allergen-specific immunotherapy. Here, we aimed at investigating the adjuvant effects of polyadenylic-polyuridylic acid (poly(A:U)), a TLR3 agonist, and R848 (resiquimod), a TLR7 agonist, in epicutaneous immunotherapy with Bet v 1, the major birch pollen allergen, to intervene in birch pollen allergy.

METHODS AND RESULTS

BALB/c mice received epicutaneous immunization (EPI) with recombinant Bet v 1 (rBet v 1) alone, or plus poly(A:U), or R848 on their depilated back using patches. Among the groups, EPI with rBet v 1 and R848 induced detectable levels of IFN-γ-producing CD4(+) T cells in lymph nodes and Bet v 1-specific IgG2a antibodies in the sera of mice. Before or after EPI, mice were sensitized with rBet v 1 plus aluminium hydroxide adjuvant and intranasally challenged with birch pollen extract. Prophylactic EPI with rBet v 1 plus R848 inhibited the production of biologically active Bet v 1-specific IgE antibodies in sensitization. Prophylactic and therapeutic EPI with rBet v 1 plus R848 suppressed lung inflammation upon challenges. Remarkably, only rBet v 1 plus R848 reduced the development of enhanced pause (PenH), a substituted parameter for airway hyper-reactivity, in challenged mice. In contrast to R848, poly(A:U) did not present adjuvant effect on the suppression of asthmatic features.

CONCLUSION

Epicutaneous immunization with rBet v 1 plus R848 induced predominant Bet v 1-specific Th1 responses and efficiently suppressed asthmatic features elicited by birch pollen. R848 could be a promising adjuvant in epicutaneous immunotherapy for birch pollen-induced allergic asthma.

Epicutaneous Immunotherapy for Aeroallergen and Food Allergy

IgE-mediated allergies today affect up to 30 % of the population in industrialized countries. Allergen immunotherapy is the only disease-modifying treatment option with a long-term effect. However, very few patients (<5 %) choose immunotherapy, due to the long treatment duration (between 3-5 years) and possible local and systemic allergic side effects of the allergen administrations. The latter occur when an allergen accidentally reaches the blood circulation. Therefore, the ideal application route for allergen immunotherapy should be characterized by two hallmarks: firstly, by a high number of potent antigen-presenting cells, which enhance efficacy and thus shorten treatment duration. Secondly, the allergen administration site is ideally non-vascularized, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized. The epidermis contains high numbers of potent antigen-presenting Langerhans cells and, as an epithelium, is non-vascularized. Therefore, the epidermis represents an interesting administration route. Historical evidence for the clinical efficacy of epicutaneous allergy immunotherapy (EPIT) has now been strengthened by a number of recent double-blinded placebo-controlled clinical trials performed by independent groups. We review the immunological rationale, history and clinical experience with epicutaneous allergy immunotherapy.

Understanding dendritic cells and their role in cutaneous carcinoma and cancer immunotherapy

Dendritic cells (DC) represent a diverse group of professional antigen-presenting cells that serve to link the innate and adaptive immune systems. Their capacity to initiate a robust and antigen-specific immune response has made them the ideal candidates for cancer immunotherapies. To date, the clinical impact of DC immunotherapy has been limited, which may, in part, be explained by the complex nature of DC biology. Multiple distinct subsets of DCs have been identified in the skin, where they can be broadly subcategorized into epidermal Langerhans cells (LC), myeloid-derived dermal dendritic cells (mDC) and plasmacytoid dendritic cells (pDC). Each subset is functionally unique and may activate alternate branches of the immune system. This may be relevant for the treatment of squamous cell carcinoma, where we have shown that the tumor microenvironment may preferentially suppress the activity of mDCs, while LCs remain potent stimulators of immunity. Here, we provide an in depth analysis of DC biology, with a particular focus on skin DCs and their role in cutaneous carcinoma. We further explore the current approaches to DC immunotherapy and provide evidence for the targeting of LCs as a promising new strategy in the treatment of skin cancer.

Transcutaneous immunotherapy via laser-generated micropores efficiently alleviates allergic asthma in Phl p 5-sensitized mice

Background

Specific immunotherapy via the subcutaneous or oral route is associated with local and, in some cases, systemic side effects and suffers from low patient compliance. Due to its unique immunological features, the skin represents a promising target tissue for effective and painless treatment of type I allergy. The current study was performed to compare the efficacy of transcutaneous immunotherapy via laser-generated micropores to subcutaneous injection.

Methods

BALB/c mice were sensitized by intraperitoneal injection of recombinant grass pollen allergen Phl p 5 together with alum. Subsequently, lung inflammation was induced by repeated intranasal challenge. During the treatment phase, adjuvant-free Phl p 5 was applied in solution to microporated skin or was subcutaneously injected. Lung function and cellular infiltration; Phl p 5–specific serum levels of IgG1, IgG2a, and IgE; and cytokine levels in bronchoalveolar lavage fluids as well as in supernatants of splenocyte cultures were assessed.

Results

Both therapeutic approaches reduced airway hyperresponsiveness and leukocyte infiltration into the lungs. Whereas subcutaneous immunotherapy induced a systemic increase in Th2-associated cytokine secretion, transcutaneous application revealed a general downregulation of Th1/Th2/Th17 responses. Successful therapy was associated with induction of IgG2a and an increase in FOXP3+ CD4+ T cells.

Conclusions

Transcutaneous immunotherapy via laser microporation is equally efficient compared with conventional subcutaneous treatment but avoids therapy-associated boosting of systemic Th2 immunity. Immunotherapy via laser-microporated skin combines a painless application route with the high efficacy known from subcutaneous injections and therefore represents a promising alternative to established forms of immunotherapy.