Lactiplantibacillus plantarum (formerly known as Lactobacillus plantarum) is a probiotic bacterium with documented effects on modulating the gut immune system, including actions relevant to Peyer’s patches. Peyer’s patches are specialized lymphoid follicles found in the small intestine and play a central role in mucosal immunity by sampling antigens and generating immune responses.

Several preclinical studies have shown that L. plantarum can interact with gut-associated lymphoid tissue (GALT), including Peyer’s patches, to influence immune cell populations and cytokine production. For example, animal studies have demonstrated that oral administration of L. plantarum can increase IgA production and promote the maturation of dendritic cells in Peyer’s patches, supporting immune surveillance and barrier function (Saeed et al., 2013).

Human data are more limited, but some clinical studies suggest immune-modulatory effects of L. plantarum strains, including increased mucosal IgA levels and enhanced vaccine responses, which may be partly mediated via Peyer’s patch activation. However, direct evidence in humans specifically linking L. plantarum to functional changes in Peyer’s patches remains limited.

Overall, the use of L. plantarum to support immune function via effects on Peyer’s patches is scientifically plausible and supported by animal and in vitro studies, but the strength of the evidence in humans is moderate.