Activated CD4+T cells from HCC stimulate macrophages to produce C-X-C motif chemokine 10(CXCL10). CXCL10 binds to the CXC chemokine receptor 3 on B cells and signals them through extracellular signal-regulated kinases, making them plasma cells that produce IgG. The gene discussed is CD4; the disease is hepatocellular carcinoma.