Influenza A H1N1 Virus Infection in Two Hematopoietic Stem Cell Transplant Recipients.

Abstract 1169

Poster Board I-191

In April 2009, a novel swine-origin influenza A (H1N1) virus (S-OIV) was identified in Mexico. Since then, several cases have been reported, with subsequent cases observed in many other countries. Clinical presentation may range from mild symptomatic patients to cases of severe clinical presentation and death due to pneumonia and respiratory failure. Definition of high risk groups are thought to be similar to those defined for seasonal influenza, including young children and elderly patients, pregnant women and patients with chronic medical conditions, especially immunocompromised hosts. Hematopoietic stem cell transplant (HSCT) recipients are at high risk for infectious complications, including severe viral infections. To our knowledge, there are no reported cases of S-OIV infection in HSCT recipients to date. The clinical features and the possible consequences of this novel influenza virus in this setting remain unknown. We describe two HSCT recipients with confirmed influenza H1N1 virus infection and a benign clinical course after oseltamivir treatment. The first case is a 12 year-old male patient with diagnosis of acute myelogenous leukemia in second complete remission who underwent an unrelated umbilical cord blood transplant with two 4/6 HLA-mismatched cord blood units. Graft-versus-host disease (GVHD) prophylaxis consisted of the association of cyclosporine and mycophenolate mofetil. Additionally, he was also being treated for an invasive aspergillosis with oral voriconazole. On day+3 after transplant, he developed fever, rhinorrhea, and dry cough. A nasal wash and a nasal swab were positive for influenza A by direct immune fluorescence and for influenza A H1N1 by real-time polymerase chain reaction (RT-PCR). Computed tomography of the nasal sinus and thorax were unremarkable. Oseltamivir therapy (75 mg po twice daily for 10 days) was initiated the same day with progressive improvement of symptoms. Oseltamivir was well tolerated and there was no interference with serum levels of cyclosporine. The second case is a 30 year-old female patient with gray zone non-Hodgkin lymphoma in relapse after autologous stem cell transplant that underwent an HLA-matched related HSCT in September 2008. She relapsed 6 months after the transplant. Cyclosporine was withdrawn. Ten days later, she developed fever rhinorrhea, and myalgia. Influenza A H1N1 was confirmed by RT-PCR of a nasal wash specimen. Treatment with a 5-day course of oseltamivir (75 mg po twice daily) was initiated and the patient had a favorable clinical course, with no complications. These two cases of confirmed influenza H1N1 virus infection in HSCT recipients with a benign clinical course highlight the need for a better understanding of the clinical course and management of this novel viral agent in severely immunocompromised hosts.