title: A phase I trial with transgenic bacteria expressing interleukin-10 in Crohn's disease.
abstract: OBJECTIVE
  The use of living, genetically modified bacteria is an effective approach for topical delivery of immunomodulatory proteins. This strategy circumvents systemic side effects and allows long-term treatment of chronic diseases. However, treatment of patients with a living, genetically modified bacterium raises questions about the safety for human subjects per se and the biologic containment of the transgene.
  
  
  METHODS
  We treated Crohn's disease patients with genetically modified Lactococcus lactis (LL-Thy12) in which the thymidylate synthase gene was replaced with a synthetic sequence encoding mature human interleukin-10. Ten patients were included in a placebo-uncontrolled trial. Patients were assessed daily for the presence of potential adverse effects by direct questioning and assessment of disease activity. We evaluated the presence and kinetics of LL-Thy12 release in the stool of patients by conventional culturing and quantitative polymerase chain reaction of LL-Thy12 gene sequences.
  
  
  RESULTS
  Treatment with LL-Thy12 was safe because only minor adverse events were present, and a decrease in disease activity was observed. Moreover, fecally recovered LL-Thy12 bacteria were dependent on thymidine for growth and interleukin-10 production, indicating that the containment strategy was effective.
  
  
  CONCLUSIONS
  Here we show that the use of genetically modified bacteria for mucosal delivery of proteins is a feasible strategy in human beings. This novel strategy avoids systemic side effects and is biologically contained; therefore it is suitable as maintenance treatment for chronic intestinal disease.
authors.affiliation: Department of Experimental Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Henri
authors.initials: H
authors.lastname: Braat
authors.forename: Pieter
authors.initials: P
authors.lastname: Rottiers
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Hommes
authors.forename: Nathalie
authors.initials: N
authors.lastname: Huyghebaert
authors.forename: Erik
authors.initials: E
authors.lastname: Remaut
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Remon
authors.forename: Sander J H
authors.initials: SJ
authors.lastname: van Deventer
authors.forename: Sabine
authors.initials: S
authors.lastname: Neirynck
authors.forename: Maikel P
authors.initials: MP
authors.lastname: Peppelenbosch
authors.forename: Lothar
authors.initials: L
authors.lastname: Steidler
mesh_terms: D002097:C-Reactive Protein / Q000032:analysis; D003424:Crohn Disease / Q000473:pathology / Q000628:therapy*; D015316:Genetic Therapy; D006801:Humans; D016753:Interleukin-10 / Q000008:administration & dosage* / Q000235:genetics; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism; D030781:Organisms, Genetically Modified; D013608:Tablets, Enteric-Coated; D013940:Thymidylate Synthase / Q000235:genetics; D019076:Transgenes
chemical_list: D013608:Tablets, Enteric-Coated; D016753:Interleukin-10; D002097:C-Reactive Protein; D013940:Thymidylate Synthase