ScRNA-seq Identifies High CXCL8 Linked to Liver Fibrosis in HBeAg-negative Chronic Hepatitis B Patients With Low...

Chemokine ligand 8 (CXCL8) is suggested as a potential biomarker in assessing the progression and severity of hepatitis B e antigen-negative treatment-naive patients with "chronic hepatitis". Analysis of CXCL8 expression in the liver and blood of such patients with low and high hepatitis B surface antigen (HBsAg) levels could provide insights into the immunopathogenesis of hepatitis B virus-related liver disease.

Thirty-five hepatitis B e antigen-negative treatment-naive patients with "chronic hepatitis" patients were classified into Group I with HBsAg levels below 2000 IU/mL (HBsAg^low, n = 12) and Group II with HBsAg levels > 2000 IU/mL (HBsAg^high, n = 23); both groups had elevated alanine aminotransferase levels (>1.2 × upper limit of normal). Histopathological analysis and plasma cytokine profiling were conducted in all 35 patients, while single-cell RNA sequencing was performed on peripheral blood mononuclear cells and intrahepatic immune cells in 6 patients.

HBsAg^low patients had higher median fibrosis scores 2(0.75-3)) compared to HBsAg^high 0(0-1). HBsAg^low were associated with increased plasma CXCL8 levels (P = .027) and higher CXCL8 expression, which correlated strongly with fibrosis scores (P = .008). Single-cell RNA sequencing of blood and liver biopsies also showed increased CXCL8, CCL2, and IL1β-expressing monocytes and macrophages in HBsAg^low. In addition, HBsAg^low patients showed distinct peripheral CD8_C2 cluster expressing GNLY, GZMH, GZMB, GZMA, ITGB1, CX3CR1, ADGRG1, CCL4, and TGFBR3 contributing to activation, cytotoxicity, and fibrosis.

Elevated CXCL8 expression in plasma, peripheral, and intrahepatic mono-mac populations, along with distinct CD8 T-cell clusters, is associated with greater fibrosis in patients with low HBsAg levels.