However, histological examination of liver sections from 25-week-old A20LPC-KO mice revealed clear signs of chronic hepatitis and steatosis (Figure 1b, Table 1), and increased B, T cell and macrophage infiltration as demonstrated by anti-B220, -CD3 and –F4/80 immunohistochemistry, respectively (Figure 1c, Supplementary Fig. S2). This evidence concerns the gene PTPRC and chronic hepatitis.