# Gut microbiota interactions with the immunomodulatory role of 25-hydroxyvitamin D in children with infectious mononucleosis

## TL;DR

This study explores how vitamin D levels and gut bacteria are linked in children with infectious mononucleosis, suggesting vitamin D may help manage immune and gut issues.

## Contribution

The study identifies specific gut microbiota changes associated with vitamin D levels in children with infectious mononucleosis.

## Key findings

- Low vitamin D levels correlate with immune dysregulation and altered gut microbiota in children with infectious mononucleosis.
- Specific gut bacteria like Anaerostipes and Acinetobacter show significant changes with vitamin D status in these children.
- Improving vitamin D deficiency may help restore gut microbiota balance and reduce immune complications.

## Abstract

Infectious mononucleosis (IM) is a childhood infectious disease caused by the Epstein–Barr virus (EBV). Its pathogenesis is associated with immune and gut microbiota disorders. Exploring the regulatory factors of immune function and gut microbiota in IM may provide novel strategies for the prophylaxis and management of this condition. This study explored the association between 25-hydroxyvitamin D (25(OH)D) level and gut microbiota abundance in children with IM.

Individuals meeting the inclusion criteria for IM were enrolled, and their blood samples were collected. The clinical manifestations, 25(OH)D levels, cytokines, and lymphocyte subsets were selected for correlation analysis. A total of 99 participants were divided into three groups, based on the level of 25(OH)D. Sixty participants completed fecal collection, including those with suboptimal 25(OH)D (n = 29) and optimal 25(OH)D (n = 31). The V3–V4 region of the 16S rRNA gene of fecal microbiota was sequenced, bioinformatics analysis was performed, and the association between the relative abundances and 25(OH)D level was analyzed.

The 25(OH)D level was positively correlated with the percentages of NK cells and B cells, and negatively correlated with IL-1β, IL-12, IL-17, TNF-α, T cells, and CTL cells (all p < 0.01). Compared with the optimal 25(OH)D group, the 25(OH)D suboptimal group showed higher relative abundances of Bacillota and Proteobacteria, and lower relative abundances of Bacteroidetes and Actinobacteriar. Compared with the optimal group, the relative abundances of Acinetobacter (LDA = 2.53, p = 0.02), Epulopiscium (LDA = 2.76, p = 0.02), and Collinsella (LDA = 3.16, p = 0.04) increased, while the relative abundances of Anaerostipes (LDA = 2.76, p = 0.042), Helicobacter (LDA = 2.79, p = 0.041), and Desulfovibrio (LDA = 2.76, p = 0.02) decreased in suboptimal group. Anaerostipes was positively correlated with 25(OH)D level (r = 0.335, p < 0.001), whereas Acinetobacter was negatively correlated (r = −0.303, p < 0.001).

The level of 25(OH)D was associated with gut microbiota and immune function in children with IM. Improving vitamin D deficiency may help maintain normal gut microbiota, ameliorate immune dysregulation, and reduce IM-related complications.