Human herpesvirus-6 (HHV-6) pneumonitis around the engraftment of cord blood transplantation (CBT) following foscarnet prophylaxis in a patient with acute leukemia

Abstract

Humanherpesvirus-6 (HHV-6) reactivation is sometimes observed in immunocompromisedpatients, especially after allogeneic stem cell transplantation. Thecomplications of HHV-6 reactivation in this setting are mainly recognized asHHV-6 encephalitis. We herein report the case of a patient who developed HHV-6pneumonitis after cord blood transplantation (CBT). A 35-year-old maleunderwent CBT for T-cell/myeloid mixed phenotype acute leukemia and achieved neutrophil engraftment on day31. He had received foscarnet as prophylaxis for HHV-6 reactivation. A computed tomography (CT) scan to evaluate the leukemic tumorshowed bilateral interstitial pneumonitis on day 33, although he had norespiratory symptoms. The findings of the CT scan were consistent withthose of HHV-6 pneumonitis that were reported previously. HHV-6 DNA, but noother pathogens, was detected in his bronchoalveolar lavage (BAL) fluid. Thepatient was successfully treated with a therapeutic dose of foscarnet. Thiscase indicates that performing a CT scan around thetime of neutrophil engraftment can play animportant role in detecting the early phase of HHV-6 pneumonia, and BAL should be considered if features consistent with HHV-6pneumonitis are observed in patients with a risk of HHV-6 reactivation.

Keywords

• human herpesvirus-6 pneumonitis
• foscarnet
• cord blood transplantation
• bronchoalveolar lavage
• computed tomography