Infections are frequent and lethal complications of acute-on-chronic liver failure (ACLF). Reliable biomarkers to distinguish fungal from bacterial infections remain limited.

Pulmonary_aspergillosis_(1)_invasive_type

Source: KGH

Histopathologic image of pulmonary invasive aspergillosis in a patient with interstitial pneumonia. Autopsy material. Grocott’s methenamine silver stain.

Given the central role of immune dysfunction in ACLF, scientists aimed to evaluate the diagnostic value of serum cytokines in differentiating invasive pulmonary aspergillosis (IPA) from bacterial pneumonia (BP) in HBV-associated ACLF.

This retrospective case-control study enrolled ACLF patients admitted to the Tongji Hospital between 2018 and 2022. Patients were categorized into IPA, BP, and non-infection groups. The BP and non-infection groups were propensity score-matched to the IPA cases. Serum cytokines levels (IL-1β, sIL-2R, IL-6, IL-8, IL-10, TNF-α) and clinical data were collected, with the diagnostic performance of these cytokines as biomarkers assessed via ROC curves.

The findings

A total of 32 IPA, 96 BP, and 96 non-infection patients were enrolled, with balanced baseline characteristics. Compared with the non-infection group, the IPA group had higher sIL-2R (1,606.00 vs. 1,211.50 U/mL, P = 0.019) and IL-6 (69.03 vs. 15.98 pg/mL, P < 0.001) levels, but lower IL-8 levels (62.20 vs. 132.00 pg/mL, P = 0.025).

The BP group showed elevated sIL-2R (1,792.00 U/mL), IL-6 (49.42 pg/mL), IL-10 (13.40 pg/mL) levels compared to the non-infection group (all P < 0.001).

Also, IL-8 was lower in the IPA group than in the BP group (62.20 vs. 176.00 pg/mL, P < 0.001) and its assessment could best distinguish IPA from BP (AUC = 0.743, cut-off = 76.60 pg/mL; sensitivity = 66.7%, specificity = 82.1%).

In conclusion, the authors found that IL-8 levels were significantly lower in patients with IPA than in patients with bacterial pulmonary infections, while IL-6 levels were significantly higher in patients with IPA compared to in non-infection controls. The combination of assessing IL-6 and IL-8 levels demonstrated superior diagnostic performance in distinguishing IPA from bacterial pulmonary infections among patients with HBV-ACLF.

The study was recently published in the Journal of Clinical and Translational Hepatology.

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