Serum interleukin-4 is elevated in clinical drug-induced liver injury

Drug-induced liver injury (DILI) remains a challenging diagnosis due to an absence of specific biomarkers. DILI due to volatile anaesthetics (VA-DILI) is characterised by trifluoroacetyl and CYP2E1 antibodies, but may not be seen for weeks after injury. Interleukin-4 (IL-4) may be involved in the production of these antibodies and may serve as a clinically useful early biomarker of VA-DILI.

To prospectively compare serum IL-4 levels between patients who develop VA-DILI and controls following exposure to the volatile anaesthetic.

A nested case-control study of patients exposed to VA during surgery was conducted. Thirteen DILI cases were identified from the original cohort, and 26 controls were matched according to age, sex and VA agent. Serum samples were collected before and 48-96 h after VA exposure, and analysed for IL-4 using quantitative enzyme-linked immunosorbent assay techniques.

There was a statistically significant difference in serum IL-4 in post-VA samples between DILI cases and controls (control: 0.030 pg/mL, IQR: 0.030 - 0.030 pg/mL vs DILI: 0.044 pg/mL, IQR: 0.030 - 0.061 pg/mL; p = 0.039). A greater proportion of DILI cases had post-VA IL-4 levels above the assay lower limit of detection compared to controls (control: 23% vs DILI: 69%; p = 0.013).

IL-4 is a potential biomarker of DILI. Clinical diagnosis and understanding of DILI disease mechanisms may be improved by further investigation of novel biomarkers, and this IL-4 signal in serum is important as proof of concept for prospective study designs.