Advances in understanding cytomegalovirus infection after transplantation.

Susceptibility to infection and disease caused by CMV varies with the degree of immunosuppression, the antecedent immunity to CMV, the source of the virus, and a complex set of host responses. These responses include the development of humoral and cellular immunity and also immunopathologic responses. HLA-restricted responses may facilitate CMV disease by facilitating the survival and activation of latently infected cells, or by facilitating MHC-class I or class II cellular immune responses underlying both protective effects and pathologic inflammation.