A proposed thaumatin-like protein (TLP) syndrome: Sensitization patterns, reaction severity, and multiple-fruit reactivity in Thai and Austrian banana-allergic adult cohorts

BACKGROUND: Banana allergy varies geographically, but molecular sensitization patterns and fruit co-reactivity remain incompletely defined. METHODS: We analyzed adults with IgE-mediated banana allergy from Thailand (n = 169) and Austria (n = 70) using banana extract-specific IgE (ImmunoCAP), ALEX (a multiplex allergen-specific IgE macroarray), and complementary line blotting. Country-stratified multivariable models assessed associations of sensitization patterns with systemic reactions and reaction severity. RESULTS: Systemic reactions predominated in Thailand (156/169, 92.3%), whereas isolated oral allergy syndrome (OAS) was more common in Austria (31/70, 44.3%). Banana extract-specific IgE was positive at ≥0.35 kUA/L in 115/168 (68.5%) Thai and 48/68 (70.6%) Austrian sera. Among samples with undetectable banana extract-sIgE (<0.10 kUA/L), molecular testing identified IgE reactivity to banana allergens or cross-reactive components in 16/18 (88.9%) Thai and 6/6 (100%) Austrian sera. ALEX-based profiling showed more heterogeneous sensitization patterns in Austria, with more frequent reactivity to nsLTPs, profilins, and latex allergens, whereas isolated ALEX reactivity to the TLP surrogate Act d 2 was common in Thailand but rare in Austria (55.6% vs 6.2%). Line blotting showed markedly more frequent IgE reactivity to TLP from banana (Mus a 4) in Thai than Austrian participants (90.5% vs 45.7%). In country-stratified analyses, TLP sensitization was independently associated with systemic reactions and greater severity in Austria. Thai estimates were imprecise because TLP sensitization was near-ubiquitous and non-systemic reactions were uncommon. CONCLUSIONS: Thai adults showed a TLP-dominant sensitization pattern, whereas Austrian profiles were more heterogeneous. TLP sensitization was associated with systemic reactions and greater severity in Austria.