A 13-year real-life study on efficacy, safety and biological effects of Vespula venom immunotherapy

Frequency of Euroglyphus maynei sensitization in respiratory allergies: a real-life study with bioinformatic analysis and geographical exploration of allergen prevalence

BACKGROUND

Dermatophagoides pteronyssinus and Dermatophagoides farinae belong to the family Pyroglyphidae (subfamily: "Dermatophagoidinae") and have the respective allergenic proteins of Der p1, Der p2, and Der p23 and Der f1 and Der f2. Euroglyphus maynei, belongs to the family Pyroglyphidae (subfamily: "Pyroglyphinae") and its main allergenic protein is Eur m1, a source of sensitization. Sensitization to D. pteronyssinus and D. farinae is assessed through skin tests, while sensitization to E. maynei is assessed less frequently.

OBJECTIVE

This experimental work aims to analyze the prevalence of sensitization to E. maynei in patients with respiratory allergies treated at M. Albanesi Allergy and Immunology Unit in Bari, Italy, and the sequence homology of major allergenic proteins of E. maynei with D. farinae and D. pteronyssinus was analyzed.

METHODS

In this real-life study, 65 patients were enrolled. In particular, patients with respiratory allergy were subjected to skin prick tests for common respiratory allergens, including Euroglyphus maynei. The sequence homology analysis was performed between the major allergenic proteins of E. maynei and those of D. pteronyssinus and D. farinae.

RESULTS

Sensitization to E. maynei accounts for 41.5% of patients. All patients with E. maynei sensitization had concomitant sensitization to D. farinae and D. pteronyssinus. The analysis of sequence homology of Der p1 and Der f1 proteins with the sequence of Eur m1 protein demonstrated an identity of 84.4% and 86%, respectively.

CONCLUSIONS

Nearly 50% of house dust mites-sensitized patients have a concomitant sensitization to E. maynei. The cross-sensitization could be due to Der f1, Der p1, and Eur m1 similarity.

Unravelling the potential of insects for medicinal purposes - A comprehensive review

Entomotherapy, the use of insects for medicinal purposes, has been practised for centuries in many countries around the world. More than 2100 edible insect species are eaten by humans, but little is known about the possibility of using these insects as a promising alternative to traditional pharmaceuticals for treating diseases. This review offers a fundamental understanding of the therapeutic applications of insects and how they might be used in medicine. In this review, 235 insect species from 15 orders are reported to be used as medicine. Hymenoptera contains the largest medicinal insect species, followed by Coleoptera, Orthoptera, Lepidoptera, and Blattodea. Scientists have examined and validated the potential uses of insects along with their products and by-products in treating various diseases, and records show that they are primarily used to treat digestive and skin disorders. Insects are known to be rich sources of bioactive compounds, explaining their therapeutic features such as anti-inflammatory, antimicrobial, antiviral, and so on. Challenges associated with the consumption of insects (entomophagy) and their therapeutic uses include regulation barriers and consumer acceptance. Moreover, the overexploitation of medicinal insects in their natural habitat has led to a population crisis, thus necessitating the investigation and development of their mass-rearing procedure. Lastly, this review suggests potential directions for developing insects used in medicine and offers advice for scientists interested in entomotherapy. In future, entomotherapy may become a sustainable and cost-effective solution for treating various ailments and has the potential to revolutionize modern medicine.

Novel approach to idursulfase and laronidase desensitization in type 2 and type 1 S mucopolysaccharidosis (MPS)

BACKGROUND

Idursulfase and laronidase are drugs used to treat Hunter syndrome (mucopolysaccharidosis type 2) and Scheie syndrome (mucopolysaccharidosis type 1 S), respectively. These are rare lysosomal storage disorders, leading to accumulation of glycosaminoglycans within lysosomes. Failure of early recognition of the disease and/or delay in starting the appropriate treatment result in severe clinical impairment and death. For almost 20 years, enzyme replacement therapy with recombinant proteins has represented the first line therapeutic option. However, administration of idursulfase and laronidase is associated with infusion-related hypersensitivity reactions, in approx. 20% of patients. In these patients, rapid desensitization by intravenous administration protocols has been used in order to avoid treatment discontinuation. This approach proved effective and safe. However, long-term tolerance could not be achieved. Thus, we decided to combine rapid desensitization with allergen immunotherapy-like desensitization.

RESULTS

Two patients with Hunter syndrome and one patient with Scheie syndrome developed severe allergy to idursulfase and laronidase, respectively, preventing them from continuing the otherwise indispensable therapy. In all three patients, the possible IgE-mediated nature of the reactions suffered was suggested by positive skin tests with the two enzymes, respectively. By devising 12-step, 3-dilution rapid desensitization protocols, we resumed the enzyme replacement therapy. However, the prolonged time required for administration (a not negligible pitfall, since therapy should be given weekly for life) and the persistent occurrence of reactions (mild but still requiring anti-allergic medication at full dosage) led us to combine rapid desensitization with a compact 11-step, 24-day allergen immunotherapy-like desensitization protocol. Thus, idursulfase and laronidase were injected subcutaneously, with a 500-fold increase from step 1 to step 11 for idursulfase and a 222-fold increase for laronidase. This strategy led to restoration of long-term tolerance, allowing weekly intravenous therapy administration under standard conditions, according to the manufacturer instructions, in the absence of side effects and with only precautionary low-dose premedication.

CONCLUSION

Rapid desensitization is a suitable and safe option in the case of idursulfase and laronidase allergy. Combination with subcutaneous allergen immunotherapy-like desensitization afforded restoration of enzyme replacement therapy given by the normal administration schedule, by inducing sustained tolerance.

Thermosensitive PLGA–PEG–PLGA Hydrogel as Depot Matrix for Allergen-Specific Immunotherapy

Allergen-specific immunotherapy (AIT) is the only currently available curative treatment option for allergic diseases. AIT often includes depot-forming and immunostimulatory adjuvants, to prolong allergen presentation and to improve therapeutic efficacy. The use of aluminium salts in AIT, which are commonly used as depot-forming adjuvants, is controversially discussed, due to health concerns and Th2-promoting activity. Therefore, there is the need for novel delivery systems in AIT with similar therapeutic efficacy compared to classical AIT strategies. In this study, a triblock copolymer (hydrogel) was assessed as a delivery system for AIT in a murine model of allergic asthma. We show that the hydrogel combines the advantages of both depot function and biodegradability at the same time. We further demonstrate the suitability of hydrogel to release different bioactive compounds in vitro and in vivo. AIT delivered with hydrogel reduces key parameters of allergic inflammation, such as inflammatory cell infiltration, mucus hypersecretion, and allergen-specific IgE, in a comparable manner to standard AIT treatment. Additionally, hydrogel-based AIT is superior in inducing allergen-specific IgG antibodies with potentially protective functions. Taken together, hydrogel represents a promising delivery system for AIT that is able to combine therapeutic allergen administration with the prolonged release of immunomodulators at the same time.

Hymenoptera Venom Immunotherapy: Immune Mechanisms of Induced Protection and Tolerance

Hymenoptera venom allergy is one of the most severe allergic diseases, with a considerable prevalence of anaphylactic reaction, making it potentially lethal. In this review, we provide an overview of the current knowledge and recent findings in understanding induced immune mechanisms during different phases of venom immunotherapy. We focus on protection mechanisms that occur early, during the build-up phase, and on the immune tolerance, which occurs later, during and after Hymenoptera venom immunotherapy. The short-term protection seems to be established by the early desensitization of mast cells and basophils, which plays a crucial role in preventing anaphylaxis during the build-up phase of treatment. The early generation of blocking IgG antibodies seems to be one of the main reasons for the lower activation of effector cells. Long-term tolerance is reached after at least three years of venom immunotherapy. A decrease in basophil responsiveness correlates with tolerated sting challenge. Furthermore, the persistent decline in IgE levels and, by monitoring the cytokine profiles, a shift from a Th2 to Th1 immune response, can be observed. In addition, the generation of regulatory T and B cells has proven to be essential for inducing allergen tolerance. Most studies on the mechanisms and effectiveness data have been obtained during venom immunotherapy (VIT). Despite the high success rate of VIT, allergen tolerance may not persist for a prolonged time. There is not much known about immune mechanisms that assure long-term tolerance post-therapy.

Association between Venom Immunotherapy and Changes in Serum Protein-Peptide Patterns

Venom immunotherapy (VIT) is administered to allergic patients to reduce the risk of dangerous systemic reactions following an insect sting. To better understand the mechanism of this treatment and its impact on the human organism, we analysed serum proteomic patterns obtained at five time-points from Hymenoptera-venom-allergic patients undergoing VIT. For statistical analyses, patients were additionally divided into two groups (high responders and low responders) according to serum sIgG4 levels. VIT was found to be associated with changes in seven proteins: the fibrinogen alpha chain, complement C4-A, complement C3, filamin-B, kininogen-1, myosin-9 and inter-alpha-trypsin inhibitor heavy chain H1. The number of discriminative m/z (mass-to-charge ratio) features increased up to the 90th day of VIT, which may be associated with the development of immunity after the administration of increased venom doses. It may also suggest that during VIT, there may occur processes involved not only in protein synthesis but also in protein degradation (caused by proteolytic venom components). The results are consistent with measured serum sIgG4 levels, which increased from 2.04 mgA/I at baseline to 7.25 mgA/I at 90 days. Moreover, the major proteomic changes were detected separately in the high responder group. This may suggest that changes in protein-peptide profiles reflect the actual response to VIT.

Long-term impact of hymenoptera venom immunotherapy on clinical course, immune parameters, and psychosocial aspects

BACKGROUND

Venom immunotherapy (VIT) is highly efficient in subjects suffering from IgE-mediated allergy to hymenoptera venom (HV), and VIT results in substantial improvement of quality of life (QoL). However, VIT-induced tolerance may be lost over time after cessation of treatment, putting patients at risk of re-sting anaphylaxis.

MATERIALS AND METHODS

To study the effect of VIT on maintenance of HV tolerance we evaluated the natural history of 54 patients who were treated with VIT up to 29 years ago, with a special focus on re-stings and their subsequent course. Furthermore, we analyzed HV-specific IgE, IgG, and IgG4 antibody titers. Finally, we assessed the long-term impact of VIT on various psychosocial aspects like dealing with hymenoptera exposures, daily life activities, self-assurance, and personal environment.

RESULTS

29 (53.7%) subjects experienced at least one re-sting after stopping VIT, with 23 (79%) showing no systemic reaction (SR). Eleven of these (37.9%) took emergency drugs as a safety measurement. Six individuals (21%) showed loss of tolerance experiencing an anaphylactic reaction. No difference in HV-specific IgE, IgG4, or IgG antibody concentrations was noticed among the different patients. Subjects who tolerated a re-sting without applying emergency drugs felt least affected in their social-behavioral leisure activities when hymenoptera were around or by anxiety for new stings.

CONCLUSION

VIT leads to long-term tolerance in the majority of HV-allergic patients, however, ~ 1/5 may lose protection over time, arguing for continued follow-up on VIT-treated subjects and keeping them equipped with an emergency kit. Notably, VIT also results in a lasting, strong impact on self-assurance and sense of well-being in individuals who tolerated a re-sting without employing emergency drugs, which emphasizes the need to use them only in case of systemic symptoms after stopping successful VIT.

Venom immunotherapy in patients with clonal mast cell disorders: IgG4 correlates with protection

BACKGROUND

Patients with clonal mast cell disorders (cMCD), systemic mastocytosis (SM) and monoclonal mast cell activation syndrome (MMAS), represent an increased risk for Hymenoptera venom anaphylaxis (HVA). Lifelong venom immunotherapy (VIT) is recommended; however, its efficacy and safety are controversial. Hence, we sought to evaluate the efficacy and safety of VIT in HVA patients with cMCD.

METHODS

A retrospective study was conducted among 46 patients with Vespula venom allergy who had experienced severe HVA, 32 cMCD (22 with SM and 10 with MMAS) and 14 controls. There were no differences between cMCD patients and controls in age (58 vs 66) and duration of VIT (47 vs 48 months), respectively.

RESULTS

During VIT, 11 (34%) cMCD patients experienced adverse reactions (ARs) (7% in controls), including 1 anaphylaxis. There were 23 re-stings in 17 (53%) patients during VIT. Of episodes, four (17%) presented with anaphylaxis, 14 (60%) presented with local reaction, and five (23%) were asymptomatic. In 11 episodes (48%), the patient did not take epinephrine, of these 8 (73%) presented with local reaction, and 3 (27%) were asymptomatic. Patient-based protection from anaphylaxis was 76% (4/17) in cMCD vs. 100% in controls during VIT. The venom-specific IgG4 concentrations increased during VIT (P < .001) although tryptase and IgE were unaltered.

CONCLUSION

Both safety and efficacy of VIT in cMCD patients were slightly reduced than controls. Severe ARs were rare. The elevated IgG4 levels may be a biomarker for efficacy of VIT in cMCD patients, as it correlates with protection from re-stings.

The size of micro-crystalline tyrosine (MCT®) influences its recognition and uptake by THP-1 macrophages in vitro

The physicochemical hallmarks of particulate immunopotentiators play a pivotal role with regards to their adjuvanticity in vivo. These properties have not been fully characterised in the case of MCT®, an amino acid-based adjuvant used as an alternative to aluminium salts in subcutaneous allergy immunotherapy (SCIT). This study presents a full characterisation of MCT® and in a preliminary capacity reveals how parameters, specifically particle size, might influence the recognition of MCT® by antigen presenting cells (APCs) in vitro. Light microscopic analysis demonstrated that MCT® was composed of highly crystalline needles, the majority of which exceeded 10 μm in length under physiological conditions (median size – 20.8 μm). While the substantial length of crystals presented a significant barrier to cellular recognition and uptake, isolated incidences of perpendicular recognition were observed owing to the smaller comparative width of crystallites (median size – 2.8 μm). This appeared to allow a small proportion of material to be ingested both fully and partially by THP-1 macrophages, although further studies are required to unequivocally confirm this observation. Preferential recognition of needle tips also favoured the direct presentation of antigen to immune cells as proteinaceous adsorption appeared to be isolated to these regions. Furthermore, the data herein provide valuable insights into the mechanisms surrounding how this adjuvant potentiates an immunological response following administration.

The large size of MCT® crystallites partially stymies their recognition and uptake by THP-1 macrophages in vitro.

Maintenance-Phase Subcutaneous Immunotherapy with House Dust Mites Induces Cyclic Immunologic Effects

BACKGROUND

Subcutaneous immunotherapy (SCIT) is an effective treatment of respiratory allergies including house dust mite (HDM) and Hymenoptera venom allergy. During the build-up phase, the allergen is administered weekly at increasing doses, while during the maintenance phase, it is administered at a fixed high dose every 4 weeks. Upon SCIT injection, the allergen is driven to the draining lymph nodes where it most likely induces an immune response. Immunologic changes are thus supposedly induced at each injection.

OBJECTIVES

It is now established that SCIT induces tolerance in the long term, but the precise underlying immunologic mechanisms remain unclear. Therefore, we wanted to analyze the immunologic changes induced in both innate and adaptive immune cells at each individual SCIT administration during the maintenance phase in HDM-allergic patients. More specifically, we wondered whether the changes in regulatory T cell (Treg) and IgE+ B cell percentages, which are observed at the end of a 3-year course of SCIT, already occurred during the maintenance phase and whether these possible changes were sustained.

METHODS

We enrolled 6 patients suffering from HDM allergic rhinitis and undergoing maintenance HDM SCIT for 18-24 months. The same SCIT extract was used for all patients. We collected blood samples at 5 time points: T1 (immediately before a given SCIT injection), T2 (9 days after T1), T3 (29 days after T1 and right before the successive administration), T4 (39 days after T1), and T5 (61 days after T1 and just before the next injection). Six non-allergic age-matched healthy individuals were used as controls. Using flow cytometry, we assessed the following cell subsets in peripheral blood mononuclear cells: CD4 and CD8 T cells, Tregs, B cells, IgE+ B cells, NK and NKT cells, and total and activated basophils.

RESULTS

HDM-allergic patients displayed increased percentages of CD4 and CD8 T cells and NK cells compared to healthy controls. In contrast, NKT cells, total B cells, and basophils were diminished. These differences were maintained throughout the time course and seemed to be independent of the periodical SCIT injections. On the contrary, Treg percentages were significantly reduced in all HDM-allergic patients at T1. However, they increased at T2 and T4 (9 days after each SCIT injection) but decreased again at T3 and T5, just before the next one, resulting in cyclic changes. IgE+ B cells were significantly increased at T1, even more increased after each administration (T2, T4), and went back to their initial levels at T3 and T5, also resulting in a cyclic pattern.

CONCLUSIONS

Our data suggest that during the SCIT maintenance phase, cycles of expansion/contraction of Tregs and IgE+ B cells occur at each SCIT injection. Therefore, the sustained induction of immune tolerance by SCIT, through the increase of Tregs, seems to depend on the periodical exposure to the allergen, at least during the early steady state.