Our observations that RRV infection of human cholangiocytes involves MAP kinase activation suggests another intriguing avenue by which viral infection might be implicated in the pathogenesis of BA, as prolonged activation of this kinase induced by a viral infection early in life might lead to unbalanced expression of cytokines such as IL-6 and IL-8, which have been associated with progression toward a severe BA phenotype. The gene discussed is CXCL8; the disease is viral infectious disease.