CD4+, CD8 + lymphocytes, CD68 + macrophages, CD14 + macrophages,1,18 and neutrophils are present in all portal tracts and in almost 70% of cases are widely distributed in the parenchyma.12,19 A subset of infants with BA demonstrate TH2 cytokine involvement,20 and other suggest a role for TH17 inflammatory pathway.21 Monocytes involvement in biliary atresia is recognized through Fas ligand expression on bile ductular epithelia.22 The gene discussed is CD4; the disease is biliary atresia.