Persistent Human Metapneumovirus Infection in Immunocompromised Child

detection of chikungunya virus using a RT-PCR/nested PCR combination .opment of a TaqMan RT-PCR assay without RNA extraction step for the detection and quantifi cation of African chikungunya viruses. To the Editor: Respiratory viral infections can be associated with a wide range of clinical manifestations from self-limiting upper respiratory tract diseases to pneumonia (1). However, in general, respiratory viral infections are more likely to progress to more severe diseases in immmu-nocompromised patients. Human metapneumovirus (hMPV) has been reported in most parts of the world as a cause of acute respiratory tract infections in persons of all age groups (2). Fatal hMPV infections have been reported in immunocompromised patients , including a 17-month-old girl who had acute lymphoblastic leuke-mia (3) and a 33-year-old woman who had received a hematopoietic stem cell transplant (HSCT) (4). In adult HSCT recipients, fatal pneumonia (5) and persistent hMPV infection without respiratory symptoms have been described (6). In addition, adult lung transplant recipients have been able to clear hMPV infection despite high levels of immunosuppression (7). We report a case of persistent hMPV infection in a child with severe combined immunodefi ciency disorder (SCID) who shed hMPV during an 11-month period. The child, a girl who was born in January 2002, received an allogeneic haploidentical stem cell transplant from her father in May 2002 after her diagnosis of SCID. Infection with infl uenza A virus (H3N2) was diagnosed on April 2005 and progressed to a chronic pneumonitis of the lin-gula. She received successive courses of anti-infl uenza agents (amantadine, oseltamivir, and zanamivir) for 1 year during which time several positive infl uenza cultures were obtained (8). Four years after the transplant, she was still lymphopenic (800 × 10 9 /L, mostly T cells) and had chronic graft-versus-host disease, which had been treated with steroids (prednisone 2.5 mg twice a day for many months). She also had a mild chronic cough but did not need supplemental oxygen while she was receiving nebulized zana-mivir (10–20 mg twice a day). Her 2 nasopharyngeal aspirate (NPA) specimens from June and July 2006 were negative for infl uenza virus. However, positive cultures for hMPV were obtained from NPA and bronchoalveolar lavage specimens collected on July 2006. After receiving this result, we performed retrospective and prospective molecular detection studies for hMPV for this patient. HMPV was detected by reverse transcription–PCR for the F and G genes (9) in 6 and 7 NPA …