It has been reported that humoral and cellular immunity in patients with biliary atresia (BA) was depressed. Ninety seven cases with BA were treated at the 1st Department of Surgery, Nagoya City University Medical School from 1970 to 1984. Most of them have suffered from severe infectious complications such as ascending cholangitis after Kasai's operation. We examined also at random the changes of the humoral and cellular immune reactions regarding plasma immunoglobulin (IgG, M, A), plasma components (C_3, C_4), white blood cell count and nitroblue tetrazolium test (NBT test) of neutrophils in 44 cases with BA before and after operation. We concluded as follows: 1) The post-operative immunoreactions in BA with good bile excretion, which are currently almost free from signs and symptoms, returned to the control levels at about two years, but those in BA with poor bile excretion or with recurrent ascending cholangitis despite bile drainage were suppressive in all their clinical courses. 2) Incidence of ascending cholangitis has decreased in about two years after Kasai's operation.
