Persistent subcutaneous nodules after immunotherapy injections for allergic asthma

Aluminum hydroxide nanoparticle adjuvants can reduce the inflammatory response more efficiently in a mouse model of allergic asthma than traditional aluminum hydroxide adjuvants

Traditional aluminum hydroxide is widely used as a vaccine adjuvant. Despite its favorable safety profile, it can cause an inflammatory response at the injection sites. However, multiple studies have shown that aluminum hydroxide nanoparticles have more potent adjuvant activity than their traditional aluminum hydroxide counterparts as antigen carriers; it has also been found that the local inflammation caused by aluminum hydroxide nanoparticle adjuvants is milder than that of other adjuvants. The aim of the present study was to compare the degree of inflammatory response between the aluminum hydroxide nanoparticle adjuvants and the traditional aluminum hydroxide adjuvants in the desensitization treatment of a mouse model of house dust mite (HDM)-induced allergic asthma. Mice were sensitized intraperitoneally with HDM. Subcutaneous desensitization was performed with PBS, traditional aluminum hydroxide adjuvants and aluminum hydroxide nanoparticle adjuvants. The mice were challenged and subsequently euthanized. The skin tissue at the local injection sites was assessed and specific indices were measured, such as the response of specific immunoglobulins, the airway hyper-responsiveness (AHR), and the inflammation in the bronchoalveolar lavage and lung tissues. Early hypersensitivity responses were suppressed in mice treated with subcutaneous immunotherapy (SCIT). Both traditional aluminum hydroxide-SCIT and aluminum hydroxide nanoparticle-SCIT could inhibit AHR. However, aluminum hydroxide nanoparticle-SCIT was able to significantly inhibit the secretion of eosinophils in the lung tissue and the production of type 2 cytokine Interleukin (IL)-5 in blood compared with the corresponding effects noted by traditional aluminum hydroxide adjuvants. Moreover, the aluminum hydroxide nanoparticle group reduced the inflammatory response at the local injection site. Collectively, the data indicated that allergen-specific immunotherapy using aluminum hydroxide nanoparticle adjuvants reduces lung and local inflammation compared with traditional aluminum hydroxide adjuvants.

Long-term clinical course and prognosis of vaccine-related persistent itching nodules (1997-2019): An observational study

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Vaccine-induced itching nodules almost always resolve over time.

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The symptoms may last up to six years though diminishing with time.

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Contact allergy to aluminium is not a cause to refrain from further vaccination.

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Vaccination can continue once the nodule has vanished and the itching has resolved.

Background

Vaccines adsorbed to aluminium can induce long-lasting intensely itching subcutaneous nodules (granulomas) at the injection site as well as contact allergy to aluminium. In clinical trials of a new acellular pertussis vaccine performed in the 1990s (Gothenburg, Sweden) with 76 000 participants, itching nodules were reported in 745 children. A positive patch test to aluminium was verified in 77% of the tested children with itchy nodules.

Aim

To describe the long-term clinical course and prognosis of vaccine-related itching nodules caused by aluminium-containing pediatric vaccines and to estimate the risk for new symptoms after future vaccination with aluminium-containing vaccines.

Methods

745 children with vaccine-related itching nodules were followed by regular interviews/questionnaires for more than 20 years. 723 of them received a booster dose of diphtheria/tetanus vaccine either with or without aluminium adjuvant during the follow-up time.

Results

Most study participants (86%) reported a full recovery from their itching nodules after a median duration of 6.6 years. Only a few of the diphtheria/tetanus-booster-vaccinated children (3%) reported mild transient itching and swelling at the new injection site.

Conclusion

Vaccine-induced itching granulomas caused by an aluminium-adsorbed acellular pertussis toxoid vaccine seem to disappear over time. Future vaccinations with aluminium-adsorbed vaccines can be performed with little risk for new itching nodules later in life.

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.

Biodegradable Metal Ion-Doped Mesoporous Silica Nanospheres Stimulate Anticancer Th1 Immune Response in Vivo

Modern vaccines usually require accompanying adjuvants to increase the immune response to antigens. Aluminum (alum) compounds are the most commonly used adjuvants in human vaccinations for infection diseases. However, alum adjuvants are nondegradable, cause side effects due to the persistence of alum at injection sites, and are rather ineffective for cancer immunotherapy, which requires the Th1 immune response. Recently, we have shown that a plain mesoporous silica (MS) adjuvant can stimulate Th1 anticancer immunity for cancer vaccines. Herein, MS nanospheres doped with Ca, Mg, and Zn (MS-Ca, MS-Mg, and MS-Zn) showed significantly higher degradation rates than pure MS. Moreover, MS-Ca, MS-Mg, and MS-Zn nanospheres  stimulated anticancer immune response and increased the CD4⁺ and CD8⁺ T cell populations in spleen. The MS-Ca, MS-Mg, and MS-Zn nanospheres with improved biodegradability and excellent ability to induce Th1 anticancer immunity show potential for clinical applications as cancer immunoadjuvants.

Aluminium adjuvants and adverse events in sub-cutaneous allergy immunotherapy

Sub-cutaneous immunotherapy is an effective treatment for allergy. It works by helping to modify or re-balance an individual’s immune response to allergens and its efficacy is greatly improved by the use of adjuvants, most commonly, aluminium hydroxide. Aluminium salts have been used in allergy therapy for many decades and are assumed to be safe with few established side-effects. This assumption belies their potency as adjuvants and their potential for biological reactivity both at injection sites and elsewhere in the body. There are very few data purporting to the safety of aluminium adjuvants in allergy immunotherapy and particularly so in relation to longer term health effects. There are, if only few, published reports of adverse events following allergy immunotherapy and aluminium adjuvants are the prime suspects in the majority of such incidents. Aluminium adjuvants are clearly capable of initiating unwanted side effects in recipients of immunotherapy and while there is as yet no evidence that such are commonplace it is complacent to consider aluminium salts as harmless constituents of allergy therapies. Future research should establish the safety of the use of aluminium adjuvants in sub-cutaneous allergy immunotherapy.

Local reactions from subcutaneous allergen immunotherapy

Local reactions from subcutaneous allergen immunotherapy are very common during the course of immunotherapy. These local reactions are not bothersome to patients. Local reactions from immunotherapy also do not predict future local or systemic reactions. This review discusses the studies that show that local reactions are not predictive of future reactions and that dose adjustments for local reactions from allergen immunotherapy are unnecessary. The article also focuses on factors that lead to patient noncompliance with immunotherapy and evaluates methods to prevent local reactions from subcutaneous allergen immunotherapy.