Abstract
The lymphocyte delayed hypersensitivity response to phytohaemagglutinin (PHA) and hepatitis B antigen (HBsAG) was evaluated by two in vitro tests-leucocyte migration inhibition and DNA synthesis. Patients convalescing from HBsAG-positive hepatits showed the presence of a state of cell-mediated immune responsiveness to the antigen. In Indian childhood cirrhosis, there was a failure of response to HBsAG and a slight but significant depression of reaction to PHA. It is suggested that the lack of immune reactivity to HBsAG, perhaps determined genetically, may be a significant factor in the evolution of cirrhosis in Indian children.