Soluble CD163 as a Biomarker of Liver Fibrosis and Inflammation in Liver Transplant Recipients

Background and Aims: Post liver transplantation (LT) inflammation and fibrosis are clinical challenges that may affect long-term outcomes. We aimed to investigate sCD163 as a biomarker of liver fibrosis in LT recipients and compare it with the Fibrosis 4 (FIB-4) score and FibroScan. Methods: In the Danish Comorbidity in Liver Transplant Recipients study (DACOLT) we included 105 LT recipients at Aarhus University Hospital. We reviewed patient records and collected plasma for measurements of sCD163 and FIB-4. Liver stiffness was assessed using FibroScan. Liver biopsies performed <6 months before or after inclusion (n = 33) were investigated by the Banff score and the METAVIR fibrosis score. Results: The majority (86%) had FibroScan with transient elastography <8 kPa. Plasma sCD163 correlated significantly with liver stiffness (ρ = 0.38, p < 0.001) and remained independently associated after multivariable adjustment (β = 0.14, p < 0.0002), corresponding to a 15.2% increase in liver stiffness per 1 mg/L increase in sCD163. In patients with liver biopsies, sCD163 levels were significantly higher in those with METAVIR stage F2–F4 compared to F0–F1 (5.04 vs. 2.35 mg/L, p = 0.018), and sCD163 correlated with histological fibrosis stage (ρ = 0.40, p = 0.029). At a cutoff of 3.86 mg/L, sCD163 identified METAVIR F2–4 fibrosis with 80% sensitivity and 85% specificity (AUC = 0.94). Conclusions: In this cohort of LT recipients, sCD163 was associated with both liver stiffness and histological fibrosis. These findings support sCD163 as a promising noninvasive biomarker for detection and monitoring of liver fibrosis post-LT, warranting evaluation in larger, prospective studies.