Introduction Hepatitis C virus (HCV) recurrence post liver transplantation (LT) is universal. Ishak score (IS) is widely used in the histological assessment of recurrent HCV. Smooth muscle actin (SMA) expression is a marker of hepatic stellate cells (HSC), while Sirius red (SR) staining primarily identifies tissue collagen. We have investigated how morphometric analysis of stellate cell activation, fibrosis and inflammatory activity can contribute to this assessment.
Methods 78 liver biopsies taken between 6 and 3722 (median 688) days post-transplant were reviewed. Sections from formalin-fixed and paraffin embedded post-tranplant liver biopsy specimens were stained with SR, for SMA and CD3 (T lymphocytes). The SR and SMA stained section were digitalised using the scanning function of a Leica DM6000. We used Image J (Version 1.42q) software and Photoshop CS5 software package for specimen analysis. SR and SMA staining proportionate area were calculated according to Calvaruso et al.1 A cell count of lobular CD3+ve lymphocytes was carried out using a microscope grid. Semi quantitative scoring was also carried out using the Ishak scoring system. Liver collagen was expressed as collagen proportionate area (CPA).
Results SR CPA, SMA CPA and CD3 count ranged from 0.26% to 29.63% (mean=6.28%), 0.00018–35.62% (mean=4.89%) and 1–63 (median=13) respectively. Mean SMA CPA and mean SR CPA for each IS category were as follows: IS 0=2.34% (0.25–5.37%), IS 1=3.29% (0–13.33%), IS 2=4.44% (0–11.56%), IS 3=6.64% (1.49–13.93%), IS 4=6.37% (6.02–6.83%), IS 5=7.92% (3.21–14.16%), IS 6=28.96% (22.30–35.62%) and IS 0=3.68% (0.59–5.83%), IS 1=4.67% (1.35–19.46%), IS 2=4.43% (0.61–10.00%), IS 3=8.65% (1.20–17.85%), IS 4=6.77% (5.10–8.43%), IS 5=9.79% (0.26–29.63%), IS 6=11.91% (1.60–22.22%) respectively. IS correlated with SMA CPA (r=0.62, p<0.0001) but not SR CPA (r=0.226, p=0.104). CD3 count also correlated with serum AST (r=0.437, p=0.004).
Conclusion Digitalisation, image analysis and immunohistochemistry for SMA and CD3+ve lymphocytes contribute to the assessment of inflammatory activity and fibrosis in post-liver transplant recurrent HCV infection.
Competing interests None declared.
Reference 1. Calvaruso, et al. Hepatology 2009;49:1236–44.