Kolkhir P, et al. Allergy Asthma Immunol Res. 2021 Jul;13(4):545-559. https://doi.org/10.4168/aair.2021.13.4.545

Background: The FAST (food allergy-specific immunotherapy) project aims at developing safe and effective subcutaneous immunotherapy for fish allergy, using recombinant hypoallergenic carp parvalbumin, Cyp c 1. Objectives: Preclinical characterization and good manufacturing practice (GMP) production of mutant Cyp (mCyp) c 1. Methods:Escherichia coli-produced mCyp c 1 was purified using standard chromatographic techniques. Physicochemical properties were investigated by gel electrophoresis, size exclusion chromatography, circular dichroism spectroscopy, reverse-phase high-performance liquid chromatography and mass spectrometry. Allergenicity was assessed by ImmunoCAP inhibition and basophil histamine release assay, immunogenicity by immunization of laboratory animals and stimulation of patients' peripheral blood mononuclear cells (PBMCs). Reference molecules were purified wild-type Cyp c 1 (natural and/or recombinant). GMP-compliant alum-adsorbed mCyp c 1 was tested for acute toxicity in mice and rabbits and for repeated-dose toxicity in mice. Accelerated and real-time protocols were used to evaluate stability of mCyp c 1 as drug substance and drug product. Results: Purified mCyp c 1 behaves as a folded and stable molecule. Using sera of 26 double-blind placebo-controlled food-challenge-proven fish-allergic patients, reduction in allergenic activity ranged from 10- to 5,000-fold (1,000-fold on average), but with retained immunogenicity (immunization in mice/rabbits) and potency to stimulate human PBMCs. Toxicity studies revealed no toxic effects and real-time stability studies on the Al(OH)₃-adsorbed drug product demonstrated at least 20 months of stability. Conclusion: The GMP drug product developed for treatment of fish allergy has the characteristics targeted for in FAST: i.e. hypoallergenicity with retained immunogenicity. These results have warranted first-in-man immunotherapy studies to evaluate the safety of this innovative vaccine.

The electronic records of 398 patients with chronic spontaneous urticaria (CSU) who had had a serum basophil histamine release assay (BHRA) performed as a marker of functional autoantibodies were audited. The BHRA was positive in 105 patients (26.4%). Fifty eight were treated with ciclosporin because they were H1 anti‐histamine unresponsive. CSU patients with a positive BHRA were more likely to respond clinically (P<0.001) and to have raised thyroid autoantibodies (P<0.02) than those with a negative BHRA. The BHRA offers a useful predictive biomarker for a good response of H1 antihistamine‐unresponsive CSU patients to ciclosporin.

Skin microdialysis (SMD) is a versatile sampling technique that can be used to recover soluble endogenous and exogenous molecules from the extracellular compartment of human skin. Due to its minimally invasive character, SMD can be applied in both clinical and preclinical settings. Despite being available since the 1990s, the technique has still not reached its full potential use as a tool to explore pathophysiological mechanisms of allergic and inflammatory reactions in the skin. Therefore, an EAACI Task Force on SMD was formed to disseminate knowledge about the technique and its many applications. This position paper from the task force provides an overview of the current use of SMD in the investigation of the pathogenesis of chronic inflammatory skin diseases, such as atopic dermatitis, chronic urticaria, psoriasis, and in studies of cutaneous events during type 1 hypersensitivity reactions. Furthermore, this paper covers drug hypersensitivity, UVB-induced- and neurogenic inflammation, and drug penetration investigated by SMD. The aim of this paper is to encourage the use of SMD and to make the technique easily accessible by providing an overview of methodology and applications, supported by standardized operating procedures for SMD in vivo and ex vivo.

Background: The positive and negative predictive values of specific IgE to penicillins are not well established for penicillin hypersensitivity. One reason may be that serum IgE levels to penicillin diminish over time. The objective in this study was to investigate variations in serum half‐life (T½) for specific IgE to penicillins (s‐IgE) and to evaluate the outcome of penicillin challenges in patients with previous but not present specific IgE to penicillins.Methods: Two subgroups were investigated. All included patients had a history of penicillin allergy with reported symptoms such as urticaria/angioedema or unclassified cutaneous rash. T½ of specific IgE to penicillins was calculated based on sera from 29 patients with repeated measurements of s‐IgE. Twenty‐two patients with a previous positive s‐IgE was followed and challenged with penicillin when IgE had become negative.Results: The T½ for s‐IgE varied between the 26 patients with decreasing s‐IgE from 1.6 months to 76.4 months and 52% had a T½ of less than a year. The three patients with stable and increasing IgE‐values showed T½ approaching infinity A total of 29 challenges with β‐lactams were performed. Four different patterns were seen when evaluating the clinical reaction to challenge (positive/negative) and post‐challenge boost of s‐IgE (yes/no). Eight (36.4%) had negative challenge and negative post‐challenge s‐IgE, eight (36.4%) negative challenge, but positive post‐challenge s‐IgE levels. 3 (13.6%) had positive challenge and positive post‐challenge s‐IgE whereas 3 (13.6%) were challenge positive, but had negative post‐challenge s‐IgE.Conclusion: Specific IgE to penicillins declines over time stressing the importance of a close time relation between diagnostic work‐up and clinical reaction. Reversal of previously positive s‐IgE may still be associated with positive penicillin challenges and/or re‐boostering of s‐IgE to positivity.