A short communication published in the British Journal of Clinical Pharmacology re-evaluates the inter- and intra-individual variability of circulating miR-122 in healthy volunteers, using small RNA sequencing generated on TAmiRNA’s miND workflow (Javid et al., 2026, doi:10.1002/bcp.70836).

Background

MicroRNA-122 (miR-122) is a liver-enriched circulating microRNA and one of the most extensively studied candidate biomarkers for drug-induced liver injury (DILI). A 2019 evaluation by Church et al. reported substantial inter- and intra-individual variability of miR-122 in healthy volunteers, which raised questions about its use as a diagnostic biomarker. The present study, conducted within the IMI2 TransBioLine consortium, set out to re-examine this variability in new, independent cohorts.

Study and findings

Plasma samples from 280 healthy volunteers were collected at three European sites (Antwerp, n = 96; Brussels, n = 124; Leeds, n = 60) under a harmonized collection protocol and analysed centrally at TAmiRNA (Vienna) using the miND® small RNA-sequencing workflow. Inter-individual variability across the three cohorts was markedly lower than previously reported: coefficients of variation of 10.7% for miR-122-5p and 16.5% for miR-122-3p, compared with values of up to 91–213% described in earlier RT-qPCR-based studies.

In a subset of 60 participants sampled on three separate occasions, including under fasting and postprandial conditions, miR-122 levels showed high temporal stability (intraclass correlation coefficients of 0.864 for miR-122-5p and 0.849 for miR-122-3p; median intra-individual CV of 4.87% for miR-122-5p). Small but statistically significant differences between sites were observed, which the authors attribute to demographic or methodological factors rather than biological instability of the marker itself.

The authors conclude that the high variability reported in earlier work likely reflects analytical factors, particularly the use of a non-human spike-in for normalization, rather than genuine biological fluctuation. Small RNA sequencing with variance-stabilizing normalization, combined with a harmonized pre-analytical protocol and centralized analysis in a single laboratory, appears to reduce technical noise substantially. Because circulating miR-122 increases by one or more orders of magnitude during hepatocellular injury, often before alanine aminotransferase (ALT) becomes abnormal, the modest baseline variability observed here does not limit its clinical utility as a DILI biomarker, provided results are interpreted relative to individual baseline levels.

Relevance for TAmiRNA

The data were generated on TAmiRNA’s miND small RNA-sequencing platform, and TAmiRNA’s Matthias Hackl and Kseniya Khamina-Kotisch contributed to sample processing and data generation as co-authors of the study. TAmiRNA’s hepatomiR® (CE-IVD) and toxomiR® assays both quantify miR-122-5p, for the assessment of liver disease, liver injury and drug- or chemical-induced organ toxicity, respectively. These findings support the analytical and biological basis for using miR-122-5p in both assays.

The TransBioLine programme has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (grant agreement no. 821283), supported by the European Union’s Horizon 2020 programme and EFPIA.

Reference

Javid I, Russomanno G, Evans A, et al. Re-evaluating variability of circulating miR-122 in healthy volunteers: Implications for biomarker qualification in drug-induced liver injury. Br J Clin Pharmacol. 2026. doi:10.1002/bcp.70836