Patients must be immunocompromised with a serious cytomegalovirus (CMV) infection. This would include pneumonia, gastrointestinal disease, hepatitis, or other organ-specific disease or severe wasting syndrome. Patients with pre-existing neutropenia or thrombocytopenia, and immediate life-threatening disease can be included if the investigator believes that delay in starting ganciclovir therapy is not advisable. In such patients, the investigator must advise the patient of the risk of further marrow suppression and the increased risk of infection or bleeding; and the patient must sign an amended informed consent form.