Human herpesvirus 6 as a possible cause of pneumonia.

Case reports and limited retrospective studies have established that human herpesvirus 6 (HHV-6) can be found in lung tissues from patients with pneumonia. Most cases of HHV-6-associated pneumonia involve immunocompromised patients, especially those who have received a bone marrow transplant or who have been infected by the human immunodeficiency virus. Additional data suggest that HHV-6 commonly reactivates in immunosuppressed individuals. The virus has been identified in a variety of organ systems, including the respiratory tract, without associated pathology. A better understanding of HHV-6 pathogenesis is needed before rational clinical intervention for HHV-6-associated pneumonias can be implemented.