Interpheron type II signature in mucosal swabs of patient with infantile colic treated with Limosilactobacillus reuteri (L. reuteri) LMG P-27481.

L. reuteri LMG P-27481 significantly upregulated CXCL9 expression in the oral mucosa of colicky infants compared to placebo.

• CXCL9 expression was quantified using Real-Time PCR in mucosal swabs from the oral mucosa.
• CXCL9 is involved in immune cell recruitment, suggesting enhanced local immune surveillance.
• Comparison was made between infants randomized to receive L. reuteri LMG P-27481 versus placebo.
• The upregulation was part of a type II interferon-stimulated gene (ISG) signature analysis.

L. reuteri LMG P-27481 significantly upregulated IDO1 expression in the oral mucosa of colicky infants compared to placebo.

• IDO1 expression was quantified using Real-Time PCR in oral mucosal swabs.
• IDO1 upregulation indicates a shift towards immune tolerance through tryptophan metabolism.
• This effect potentially reduces mucosal hyperreactivity.
• IDO1 was one of five ISGs analyzed alongside CXCL9, HLA-DRA, STAT1, and CXCL10.

L. reuteri LMG P-27481 significantly upregulated HLA-DRA expression in the oral mucosa of colicky infants compared to placebo.

• HLA-DRA expression was quantified using Real-Time PCR in oral mucosal swabs.
• Increased HLA-DRA expression implies improved antigen presentation capacity, contributing to balanced immune regulation.
• HLA-DRA was among five type II ISGs analyzed in the study.
• The upregulation was observed in infants randomized to the L. reuteri treatment group versus placebo.

STAT1 and CXCL10 were analyzed as part of the type II interferon signature but were not reported as significantly upregulated compared to placebo.

• Five genes were analyzed: CXCL9, IDO1, HLA-DRA, STAT1, and CXCL10.
• Only CXCL9, IDO1, and HLA-DRA were specifically reported as significantly upregulated in the L. reuteri group.
• FABP4 was used to confirm treatment-related changes in expression.
• Gene expression was measured via Real-Time PCR in oral mucosal swabs.

L. reuteri LMG P-27481 modulates mucosal immunity in the oral mucosa, extending its immunological effects beyond the gastrointestinal tract.

• The study used oral mucosal swabs rather than gut samples to assess immune gene expression.
• The immunomodulatory effect was characterized as influencing type II interferon-stimulated gene expression.
• The authors suggest this effect may complement L. reuteri's known action on gut microbiota.
• The findings offer 'new therapeutic perspectives for infant colic and other pediatric inflammatory conditions.'

Infantile colic is associated with gut microbiota alterations and immune dysregulation characterized by an imbalance between pro-inflammatory and regulatory pathways.

• The study was conducted in the context of increasingly recognized links between colic and gut microbiota.
• Immune dysregulation in colic involves imbalance between pro-inflammatory and regulatory immune pathways.
• Lactobacillus reuteri DSM17938 has been previously shown to reduce crying time in colicky infants.
• The immunological mechanisms of L. reuteri in infantile colic remained unclear prior to this study.