CD40LG and cytomegalovirus infection: In a study where the amount and distribution of immunoglobulin deposits in liver biopsies from infants with BA were studied and correlated to the results to the CMV infection status, it was found that the intensity for IgM deposits was significantly higher in biopsies from patients with BA infected with CMV than in those without CMV infection, supporting the theory that a CMV infection may trigger immunologic mechanisms in the pathogenesis of BA [27].