Measuring Changes in Blood in Patients at High Risk of Cytomegalovirus Infection After Undergoing Donor Bone Marrow Transplant or Peripheral Blood Stem Cell Transplant

DISEASE CHARACTERISTICS: * Meets 1 of the following criteria at the City of Hope National Medical Center: * Patient who has undergone a matched-related or matched-unrelated allogeneic bone marrow or peripheral blood stem cell transplantation (SCT) for a hematological malignancy (e.g., aplastic anemia or myelodysplastic syndromes) * At risk for cytomegalovirus (CMV) infection and disease due to 1 of the following risk factors: * CMV-seropositive prior to transplantation * Received SCT from a CMV-seropositive donor * Donor for matched-related SCT * Healthy volunteer evaluated concurrently with SCT recipients to establish normal values for both CMV-seronegative and CMV-seropositive persons * Any HLA serotypes allowed PATIENT CHARACTERISTICS: * See Disease Characteristics PRIOR CONCURRENT THERAPY: * See Disease Characteristics