The Role of microRNAs and Cell-Free DNAs in Fungal Infections: Systematic Review and Meta-Analysis of the Literature.

BACKGROUND: Invasive fungal infections (IFIs) remain a major cause of morbidity and mortality among immunocompromised patients, despite advances in antifungal therapy. Conventional diagnostics are limited, highlighting the need for novel biomarkers. Circulating microRNAs (miRNAs) and cell-free DNA (cfDNA) have emerged as promising tools due to their roles in immune regulation, pathogen-host interactions, and disease monitoring. This systematic review and meta-analysis evaluate their diagnostic and prognostic potential in fungal infections. METHODS: A systematic search of PubMed, Web of Science, SCOPUS, and EMBASE was conducted up to May 2025 in line with PRISMA guidelines (PROSPERO protocol CRD42021287150). Eligible studies included clinical research on confirmed fungal infections assessing cfDNA or miRNAs. Random-effects meta-analyses were performed for cfDNA, and miRNA findings were synthesized descriptively. RESULTS: In total, 526 studies were included. cfDNA positivity was observed in 12% of all tested samples (95% CI: 0.06-0.22) and in 79% of patients with proven fungal infections (95% CI: 0.62-0.90), supporting its value as a minimally invasive, culture-independent diagnostic marker. Six studies on miRNAs identified disease-specific signatures, including miR-132 and miRNA panels for aspergillosis, with high diagnostic accuracy (AUC ≥ 0.98). miR-146a, miR-223, and miR-545 further correlated with prognosis and mortality. CONCLUSIONS: cfDNA and miRNAs show strong potential for early diagnosis, prognosis, and treatment monitoring in IFIs. Standardized methodologies and large-scale validation are essential for clinical translation.