Jianpi Yiqi Busui Formula attenuates immune dysregulation in myasthenia gravis: Associations with gut microbiota remodeling and the Treg LDHA-lactate-H3K18la-PD-1 axis

BACKGROUND: Myasthenia gravis (MG) is an autoimmune neuromuscular disorder in which immune dysregulation and altered T-cell homeostasis contribute to pathogenic autoantibody production. Jianpi Yiqi Busui Formula (JPYQBSF) is used as an adjunctive traditional Chinese medicine, but its immunometabolic mechanisms remain incompletely defined. PURPOSE: To evaluate the clinical and preclinical effects of JPYQBSF and to examine whether gut microbiota remodeling and the regulatory T-cell (Treg) LDHA-lactate-H3K18la-PD-1 axis are associated with its immunomodulatory activity. STUDY DESIGN: An exploratory prospective clinical cohort, an experimental autoimmune myasthenia gravis (EAMG) rat model, and multi-omics and mechanistic experiments were integrated. METHODS: Thirty-one anti-acetylcholine receptor antibody-positive MG patients receiving stable conventional therapy were assessed before and after 24 weeks of adjunctive JPYQBSF, with 31 age- and sex-matched healthy participants as a reference group. EAMG rats underwent functional, electrophysiological, immunological, 16S rRNA, serum metabolomic, and TMT-proteomic analyses. Fecal microbiota transplantation, human Treg-cell experiments, pharmacological LDH inhibition, LDHA knockdown, ChIP-qPCR, CUT&Tag, and reporter assays were used to interrogate candidate pathways. RESULTS: In the clinical cohort, adjunctive JPYQBSF was associated with lower AChR-Ab levels and partial normalization of inflammatory and immunoregulatory markers; the uncontrolled design precludes attribution of these changes to JPYQBSF alone. In EAMG rats, JPYQBSF improved motor and electrophysiological outcomes, reduced inflammatory mediators, and shifted the Treg/Th17 balance. Microbiome, metabolomic, and proteomic analyses identified treatment-associated community and metabolic changes, including aromatic lactic-acid derivatives and LDHA. In cultured Tregs, JPYQBSF exposure increased LDHA expression, lactate, H3K18la enrichment near the PDCD1 promoter, and PD-1 expression. Oxamate and LDHA knockdown attenuated several of these changes, whereas healthy-donor FMT partially reproduced selected immunometabolic effects. CONCLUSION: The findings support a coordinated model in which gut microbiota remodeling and LDHA-dependent Treg immunometabolic changes contribute to the effects of JPYQBSF. They do not establish a direct linear causal pathway from specific microbial metabolites to H3K18 lactylation, PD-1 regulation, or independent clinical efficacy.