Multi-Country IgE Reactivity of Blo t 2 Isoforms as a Potential Biomarker for Asthma Severity

Title: Multi-country IgE reactivity profiling of Blo t 2 isoforms and asthma severity implications

• The study focuses on Blomia tropicalis, a notable source of inhalant allergens in Southeast Asia and Latin America, and examines the clinical relevance of Blo t 2 isoforms in Latin American populations, with particular attention to asthma phenotypes.

coli Shuffle T7 and purified by cation-exchange chromatography.

• Two recombinant Blo t 2 isoforms, rBlo t 2.2 and rBlo t 2.5, were produced in E.
• Structural validation employed mass spectrometry and Fourier-transform infrared spectroscopy.
• Additional assessments included proteolytic stability, lipopolysaccharide (LPS) binding, IgE reactivity, and allergenic activity via Western blot, ELISA, and mediator release assays.
• Sensitization patterns were evaluated using serum samples from Blomia tropicalis-allergic individuals with and without asthma across Brazil, Colombia, and Ecuador.

• Both isoforms exhibited correct folding with intact disulfide bonds and demonstrated resilience to endolysosomal proteases.
• rBlo t 2.2 showed an absence of specific LPS-binding activity and displayed reduced cross-reactivity with rDer p 2.
• Across the three countries, the average IgE sensitization rate to rBlo t 2.2 was approximately half of the study population, with country-specific observations ranging from mid-teens to just over half of participants.
• Notably, sera from Ecuador exhibited the highest IgE reactivity in this cohort.
• Within Brazil, rBlo t 2.2 elicited higher IgE binding than rBlo t 2.5.
• Sensitization to rBlo t 2.2 correlated with severity, being more frequent in patients with severe asthma compared with individuals with mild asthma or rhinitis.

• rBlo t 2.2 is characterized as a stable, mid-tier to major isoform with potential utility as a biomarker for severe asthma, particularly in Brazilian populations.
• The findings support consideration of rBlo t 2.2 in molecular diagnostic panels for Blomia tropicalis allergy.

• The study notes the need for larger sample sizes and multivariate analyses to validate associations and generalize across populations.