title: Respiratory infections: do we ever recover?
abstract: Although the outcome of respiratory infection alters with age, nutritional status, and immunologic competence, there is a growing body of evidence that we all develop a unique but subtle inflammatory profile. This uniqueness is determined by the sequence of infections or antigenic insults encountered that permanently mold our lungs through experience. This experience and learning process forms the basis of immunologic memory that is attributed to the acquired immune system. But what happens if the pathogen is not homologous to any preceding it? In the absence of cross-specific acquired immunity, one would expect a response similar to that of a subject who had never been infected with anything before. It is now clear that this is not the case. Prior inflammation in the respiratory tract alters immunity and pathology to subsequent infections even when they are antigenically distinct. Furthermore, the influence of the first infection is long lasting, not dependent on the presence of T and B cells, and effective against disparate pathogen combinations. We have used the term "innate imprinting" to explain this phenomenon, although innate education may be a closer description. This educational process, by sequential waves of infection, may be beneficial, as shown for successive viral infections, or significantly worse, as illustrated by the increased susceptibly to life-threatening bacterial pneumonia in patients infected with seasonal and pandemic influenza. We now examine what these long-term changes involve, the likely cell populations affected, and what this means to those studying inflammatory disorders in the lung.
authors: Kennedy Institute for Rheumatology, Imperial College London, 1 Aspenlea Road, London W6 8LH, UK.
authors: John
authors: J
authors: Goulding
authors: Robert
authors: R
authors: Snelgrove
authors: José
authors: J
authors: Saldana
authors: Arnaud
authors: A
authors: Didierlaurent
authors: Mary
authors: M
authors: Cavanagh
authors: Emily
authors: E
authors: Gwyer
authors: Jeremy
authors: J
authors: Wales
authors: Erika L
authors: EL
authors: Wissinger
authors: Tracy
authors: T
authors: Hussell
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D008208:Lymphatic System / Q000276:immunology; D012038:Regeneration; D020545:Respiratory Mucosa / Q000502:physiology; D012141:Respiratory Tract Infections / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000906:Antibodies