title: A lurking threat: transfer of peanut allergy through peripheral blood stem cell transplantation.
abstract: BACKGROUND
  There exist several reports of atopy and allergen-specific IgE-mediated hypersensitivity transferred by bone marrow transplantation, and it has been concluded that the transfer of allergic reactivity results from adoptive transfer of IgE-producing donor-derived B- and/or plasma cells. To the best of our knowledge we report the first case of peanut allergy after PBSCT.
  
  
  METHODS
  A 55-year-old anciently non allergic man with secondary acute myeloid leukemia (AML) received an allogeneic peripheral blood stem cell transplantation from a matched unrelated donor following reduced-intensity conditioning. On day 32 after PBSCT, while still on prophylactic systemic immunosuppression, the patient noticed a first episode of angioedema with swelling of the nasal and oral mucosa 30 min after consuming peanut puffs. In a second episode, eight months after PBSCT, he again developed angioedema, generalized pruritus and nausea within minutes after eating biscuits containing hazelnut and peanut. Moreover, after topical application of a peanut oil-containing ointment, the patient experienced facial erythema and angioedema. Nine months after PBSCT an evaluation for peanut allergy revealed a highly increased specific IgE to peanut of 75.9 kU/l. Accordingly, skin prick tests for peanut extract were also positive. In consequence, the patient was counseled to strictly avoid peanut-related products, and provided with an emergency set. No adverse allergic events have occurred since for an observation time of 15 months after PBSCT. The stem cell donor was contacted and confirmed intolerance to peanuts. His specific serum IgE pattern nine month after PBSCT harvest was analysed and showed similar sensitization profiles compared to those of the transplant recipient.
  
  
  CONCLUSIONS
  Because of the close temporal association between the onset of allergic symptoms in the PBSC recipient it is reasonable to assume that the acquired peanut allergy had been transferred from the donor to the recipient by the PBSC graft.
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Medical Center, Georg August University Göttingen, Göttingen, Germany ; Department of Dermatology and Venereology, University Medical Center, Rostock, Germany.
authors.forename: Birka
authors.initials: B
authors.lastname: Brauns
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Medical Center, Georg August University Göttingen, Göttingen, Germany ; Lower Saxony Institute of Occupational Dermatology, University Medical Center Göttingen and University of Osnabrück, Osnabrück, Germany.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Schön
authors.affiliation: Department for Hematology and Oncology, University Medical Center, Georg August University, Göttingen, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Wulf
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Medical Center, Georg August University Göttingen, Göttingen, Germany ; Lower Saxony Institute of Occupational Dermatology, University Medical Center Göttingen and University of Osnabrück, Osnabrück, Germany ; Dermatology Office, Elmshorn, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Mempel
keywords: Allergy transfer; IgE-mediated hypersensitivity; Peanut allergy; Stem cell transplantation