A specific immune response to purified HA antigen (HAAg) demonstrated by leukocyte migration inhibition in patients recovering from viral hepatitis A.

The mechanism responsible for liver cell necrosis in patients with hepatitis A is not known. Since the type of hepatic lesions and the clinical presentation of acute hepatitis B are similar and are probably related to the cell-mediated immune response to a viral antigen located in the liver cell, it is possible that a similar mechanism is involved in hepatitis A. In the present paper, immune reactivity to hepatitis A antigen (HAAg) was measured in 13 patients at the time of recovery from hepatitis A, by using the leukocyte migration inhibition test (LMIT) under agarose with purified HAAg as antigen. Eleven normal subjects without history of hepatitis and 4 patients convalescent from hepatitis B were used as controls. Inhibition of leukocyte migration by HAAg was found in 11 of the 13 patients, with an average migration index (MI) of 77.0% (SEM 3.5). No such inhibition was found in any of the controls: MI = 100.8% (SEM 1.0), P less than 0.0001. These findings show that, like for HBsAg in hepatitis B, an immune response specific for HAAg can be demonstrated by the LMIT after HAV infection. This response could perhaps be related to the liver injury associated to hepatitis A.