BACKGROUND: Several reports in selected populations suggest that human rhinovirus (HRV) may be responsible for lower respiratory tract infections or pneumonia. We describe clinical features of all patients with rhinovirus cultured from their bronchoalveolar lavage (BAL) during a 10-yr period in a tertiary care center. METHODS: Results for viral culture of all lower respiratory specimens performed during a 10-year period at the University of Virginia Health Sciences Center were reviewed. A case was defined as any patient with a positive culture for HRV in a BAL specimen. A comprehensive review of the patients\' medical records was performed. In one case, in situ hybridization (ISH) was performed in order to identify whether rhinoviral RNA was present in bronchial biopsy specimens. RESULTS: During the 10-year study period viruses were identified in 431 lower respiratory tract specimens, and were most frequently cytomegalovirus or herpes simplex virus. Twenty patients (ages, 2.5-86 year) had a bronchoalveolar specimen culture positive for HRV. All had an abnormal chest radiograph, 60% were admitted to the intensive care unit, and 25% expired during their hospitalization. In 18 patients (90%) various severe underlying conditions were identified including solid organ transplants in seven, malignancies in four and AIDS in two. An immunosuppressive disease or condition requiring immunosuppressive therapy was present in all cases. In addition to HRV, one or more potential pathogens were identified in respiratory specimens from 14 patients (70%). Histopathological abnormalities, ranging from fibropurulent debris in alveoli to diffuse alveolar damage, were present in 6 of 13 bronchial biopsies. In two cases without any other significant pathogens than HRV, acute inflammations with fibropurulent debris in alveoli were observed. One lung transplant patient showed intermittent recovery of HRV in her respiratory specimens during a 15-week time period, but ISH did not show HRV RNA in bronchial epithelial cells. CONCLUSION: Our observations suggest that HRV recovery from BALs or lower respiratory tract samples in highly immunocompromised patients is associated with severe lower respiratory tract illness. Whether HRV directly causes viral pneumonia or predispose to pulmonary injury and/or superinfection remains uncertain.