Utilizing the Banana S-Adenosyl-L-Homocysteine Hydrolase Allergen to Identify Cross-Reactive IgE in Ryegrass-, Latex-, and Kiwifruit-Allergic Individuals.

Food allergies mediated by specific IgE (sIgE) have a significant socioeconomic impact on society. Evaluating the IgE cross-reactivity between allergens from different allergen sources can enable the better management of these potentially life-threatening adverse reactions to food proteins and enhance food safety. A novel banana fruit allergen, S-adenosyl-L-homocysteine hydrolase (SAHH), has been recently identified and its recombinant homolog was heterologously overproduced in E. coli. In this study, we performed a search in the NCBI (National Center for Biotechnology Information) for SAHH homologs in ryegrass, latex, and kiwifruit, all of which are commonly associated with pollen-latex-fruit syndrome. In addition, Western immunoblot analysis was utilized to identify the cross-reactive IgE to banana SAHH in the sera of patients with a latex allergy, kiwifruit allergy, and ryegrass allergy. ClustalOmega analysis showed more than 92% amino acid sequence identity among the banana SAHH homologs in ryegrass, latex, and kiwifruit. In addition to five B-cell epitopes, in silico analysis predicted eleven T-cell epitopes in banana SAHH, seventeen in kiwifruit SAHH, twelve in ryegrass SAHH, and eight in latex SAHH, which were related to the seven-allele HLA reference set (HLA-DRB1*03:01, HLA-DRB1*07:01, HLA-DRB1*15:01, HLA-DRB3*01:01, HLA-DRB3*02:02, HLA-DRB4*01:01, HLA-DRB5*01:01). Four T-cell epitopes were identical in banana and kiwifruit SAHH (positions 328, 278, 142, 341), as well as banana and ryegrass SAHH (positions 278, 142, 96, and 341). All four SAHHs shared two T-cell epitopes (positions 278 and 341). In line with the high amino acid sequence identity and B-cell epitope homology among the analyzed proteins, the cross-reactive IgE to banana SAHH was detected in three of three latex-allergic patients, five of six ryegrass-allergic patients, and two of three kiwifruit-allergic patients. Although banana SAHH has only been studied in a small group of allergic individuals, it is a novel cross-reactive food allergen that should be considered when testing for pollen-latex-fruit syndrome.

rBet v 1a-BanLecwt induce upregulation of IL-10 and IFN-γ gene expression in Caco-2/THP-1 co-culture and secretion of IL-10 and IFN-γ/IL-4 levels in PBMCs of birch pollen allergic donors.

Novel allergen immunotherapy (AIT) approaches necessitate the use of more effective and safe therapeutics, which can be accomplished by employing novel adjuvants for improved innate immune cell activation, as well as hypoallergenic allergen forms. In this study, we investigate the immunomodulatory effects of a chimera rBet v 1a-BanLecwt (rBv1a-BLwt; Cwt) composed of the major birch pollen allergen Bet v 1a and banana lectin (BanLecwt; BLwt) and two novel chimeras, rBv1l-BLH84T (rBet v 1l-BanLecH84T; C1) and rBLH84T-Bv1l (rBanLecH84T-Bet v 1l; C2), both composed of BLH84T and hypoallergenic birch pollen allergen Bv1l in the co-culture model Caco-2/THP-1, and PBMCs from donors with birch pollen allergy. The chimeric molecules rBv1l-BLH84T (C1) and rBLH84T-Bv1l (C2) were created in silico and then produced in E. coli using recombinant DNA technology. Real-time PCR analysis of gene expression following compound treatment in the co-culture model revealed that all three chimeras have the potential to induce the anti-inflammatory cytokine IL-10 gene expression in Caco-2 cells and IFN-γ gene expression in THP-1 cells. Sandwich ELISA revealed that Cwt increased IL-10 secretion and IFN-/IL-4 levels in PBMCs from birch pollen allergic donors, whereas C1 and C2 were less effective. The findings suggest that Cwt should be analyzed further due to its potential benefit in AIT.

Thyroglobulin specific IgE and a possible link to suspected penicillin induced allergic skin manifestations - cross sectional study.

Porcine thyroglobulin was important in the discovery of alpha-Gal allergy. Here, the linkage of porcine thyroglobulin-specific IgE with IgE positivity to routinely assessed allergens and to the incoming diagnosis within a population of suspected atopic individuals is explored. IgE, IgA, total IgG and IgG subclasses to porcine thyroglobulin, IgE to bovine, human thyroglobulin and meat extract were measured with ELISA. The following correlations were observed in IgE binding to porcine and bovine thyroglobulin (r = 0.910, p = 1x10-17), porcine and human thyroglobulin (r = 0.635, p = 4x10-6), human and bovine thyroglobulin (r = 0.746, p = 6x10-9) and porcine thyroglobulin and meat extract (r = 0.482, p = 0.0009). Only one out of ten samples which showed binding to porcine thyroglobulin in ELISA tested positive with ImmunoCAP alpha-Gal, implying different epitope/s. Increased IgE binding was detected towards a more electronegative fraction of porcine thyroglobulin separated according to charge and the binding could be partially inhibited by galactose. Anti-thyroglobulin IgE was found in 29.7% of the population, in subjects who were significantly younger, p < 0.0001 and it occurred more frequently in patients referred for testing penicillin specific IgE (OR 2.48, p = 0.0059) and were negative. IgE specific to porcine, bovine and possibly human thyroglobulin may be implicated in post-infectious skin manifestation misinterpreted as penicillin allergy.

Immediate allergic reaction to methylprednisolone with tolerance of other corticosteroids.

INTRODUCTION: In spite of the wide usage of corticosteroids for the treatment of a plethora of diseases, sometimes they can induce immediate hypersensitivity reactions, which are however uncommon. CASE OUTLINE: We report a case of immediate allergic reaction induced by intravenous methylprednisolone given before operation for surgical repair of an arm contracture as a sequel of burns, which the child had tolerated a month before. Six weeks later the patient repeated the anaphylactic reaction during skin testing to methylprednisolone. In addition, basophile activation test with methylprednisolone (BAT) was positive. CONCLUSION: This case report describes a patient who experienced intraoperative anaphylaxis and anaphylactic reaction induced by skin testing. This is the first report on induction of both anaphylactic reactions by methylprednisolone in the same child. Clinical findings, positive BAT and positive skin tests with methylprednisolone imply that the child developed type-I hypersensitivity. The lack of crossreactivity with other corticosteroids emphasizes that the reactions were caused by the steroid molecule.