Mechanism 1.Immunity (1 acute postviral infection immune complex(viral Ag and Ab) connect with platelet Fc-R viral components banding with platelet auto Ab generation (2) chronic: not affected by foreign AgMechanism 1.Immunity （1）acute： postviral infection immune complex (viral Ag and Ab) connect with platelet Fc-R viral components banding with platelet auto Ab generation （2）chronic：not affected by foreign Ag