title: Comparable humoral response after two doses of adjuvanted influenza A/H1N1pdm2009 vaccine or natural infection in allogeneic stem cell transplant recipients.
abstract: BACKGROUND
  The present study evaluated immunogenicity and tolerance of two-dose influenza A/H1N1pdm09 vaccination in allogeneic hematopoietic stem cell transplantation (HSCT) recipients, and compared the vaccine-induced humoral response to that triggered by natural infection in another group of HSCT patients.
  
  
  METHODS
  Adult allogeneic HSCT recipients vaccinated with two doses of influenza A/H1N1pdm09 vaccine, separated by 3 weeks, and patients with proven influenza A/H1N1pdm09 infection were included. Antibody responses were measured by hemagglutination-inhibition assay 1) on days 0, 21, 42 and 6 months after the first vaccine injection in vaccinated patients and 2) before pandemic and after influenza A/H1N1pdm09 infection, in patients presented natural infection.
  
  
  RESULTS
  At baseline, 3% of 59 recipients of adjuvanted vaccine and 0% of 20 infected patients were seroprotected (antibody titer≥1/40). Seroprotection rate observed 42 days after vaccination was not different from that observed after natural infection (66% and 60% respectively, p=0.78). In vaccinated patients, seroprotection rate increased significantly from 54% to 66% between day 21 and 42 (p=0.015). Moreover, after 6 months, seroprotection rate in 21 vaccinated patients was similar to that observed in 10 infected patients evaluated at least 76 days after infection (D76-217) (60% and 81% respectively, p=0.2). In multivariate analysis, no immunosuppressive treatment or chronic graft-versus-host disease (GVHD) and longer time between transplantation and vaccination/infection were associated with a stronger humoral response. The adjuvanted vaccine was safe with low rate of GVHD worsening.
  
  
  CONCLUSIONS
  In HSCT recipients, two doses of influenza A/H1N1pdm09 adjuvanted vaccine were safe and induced a humoral response comparable to that triggered by natural infection in these patients.
authors: Service d'Hématologie-Adolescents Jeunes Adultes, Hôpital Saint-Louis, AP-HP, Paris, France; Service d'Hématologie, Groupe Hospitalier Pitié Salpêtrière, AP-HP, Paris, France. Electronic address: nathalie.dhedin@sls.aphp.fr.
authors: Nathalie
authors: N
authors: Dhédin
authors: Service de Virologie, Hôpital Saint-Vincent-de-Paul Cochin, AP-HP, Paris, France.
authors: Anne
authors: A
authors: Krivine
authors: UPMC Université Paris 06, UMR S 945, Laboratory Immunity and Infection, F-75013 Paris, France; INSERM, UMR S 945, Laboratory Immunity and Infection, F-75013 Paris, France.
authors: Nicole
authors: N
authors: Le Corre
authors: Unité de Recherche Clinique, Groupe Hospitalier Pitié Salpêtrière, Paris, France.
authors: Alain
authors: A
authors: Mallet
authors: Département d'Hématologie, Hôpitaux Universitaires Strasbourg, France.
authors: Bruno
authors: B
authors: Lioure
authors: Service d'Hématologie, Centre Hospitalier-Universitaire Estaing, Clermont-Ferrand, France.
authors: Jacques-Olivier
authors: JO
authors: Bay
authors: Service d'Hématologie, Hôpital Saint-Antoine, AP-HP, Paris, France.
authors: Marie-Thérèse
authors: MT
authors: Rubio
authors: Service d'Hématologie et d'Oncologie médicale. Centre Hospitalier Universitaire de la Réunion. Hôpital Felix Guyon, Saint Denis, Réunion, France.
authors: Philippe
authors: P
authors: Agape
authors: Service d'Hématologie, Hôpital Michallon, Grenoble, France.
authors: Anne
authors: A
authors: Thiébaut
authors: Service de virologie, Hôpital Saint-Louis, AP-HP, Paris, France; Université Paris-Diderot, Sorbonne Paris, Cité, Paris, France.
authors: Jérôme
authors: J
authors: Le Goff
authors: UPMC Université Paris 06, UMR S 945, Laboratory Immunity and Infection, F-75013 Paris, France; INSERM, UMR S 945, Laboratory Immunity and Infection, F-75013 Paris, France.
authors: Brigitte
authors: B
authors: Autran
authors: Université Paris-Diderot, Sorbonne Paris, Cité, Paris, France; Service d'Hématologie-Greffe de Moelle, Hôpital Saint-Louis, AP-HP, Paris, France.
authors: Patricia
authors: P
authors: Ribaud
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D005260:Female; D006086:Graft vs Host Disease; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007115:Immunization Schedule; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines
keywords: Hematopoietic stem cell transplantation; Humoral immune response; Influenza A/H1N1pdm09 infection; Influenza vaccination