Microbial Transglutaminase as a Candidate Nutritional Adjuvant: An Evidence-Based Evaluation Using ASIA Syndrome Criteria

Microbial transglutaminase (mTG) is a food-processing enzyme widely used for protein cross-linking in processed foods. Experimental, serological, and disease-specific studies suggest that mTG and mTG-modified protein complexes may possess immunogenic and pro-inflammatory properties, particularly in the context of celiac disease. Through transamidation and cross-linking, mTG can generate post-translationally modified protein complexes and neo-epitopes that may interact with host immune pathways. This review critically evaluates the available evidence relevant to mTG within the autoimmune/inflammatory syndrome induced by adjuvants (ASIA) framework. The evidence is strongest for dietary exposure and mTG-associated immunogenicity, whereas evidence for mTG-specific clinical manifestations, improvement after selective withdrawal, systemic autoimmunity, and causal ASIA induction remains limited or indirect. Accordingly, mTG should currently be considered a candidate nutritional/environmental adjuvant rather than a clinically validated ASIA-inducing factor. These observations warrant further independent investigation of human exposure, gastrointestinal biological activity, dose-response relationships, susceptible populations, immunological biomarkers, and long-term safety.