title: Immunosenescence and pneumococcal disease: an imbalance in host-pathogen interactions.
abstract: Respiratory infections are among the most important causes of morbidity and mortality from infectious diseases worldwide. The most common causative bacterium, Streptococcus pneumoniae, frequently colonises the upper respiratory tract, where it resides mostly asymptomatically. Occasionally, however, S pneumoniae can cause severe disease such as pneumonia. Local host immunity is essential to control colonising pathogens by preventing overgrowth, spread, and invasion. However, age-related immune deficits in elderly people, known as immunosenescence, might contribute to increased disease burden. We review present knowledge about immunosenescence in the respiratory tract against Gram-positive bacteria, particularly S pneumoniae. We discuss the possible underdetection of pneumococcal colonisation in elderly people, and suggest changes to present surveillance methods to improve understanding of the relation between colonisation and disease. We conclude that present knowledge about alteration of host-pathogen interactions by immunosenescence in the respiratory tract is insufficient, and that research is needed to enable improved measures for prevention.
authors: Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
authors: Cassandra L
authors: CL
authors: Krone
authors: Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
authors: Kirsten
authors: K
authors: van de Groep
authors: Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
authors: Krzysztof
authors: K
authors: Trzciński
authors: Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
authors: Elizabeth A M
authors: EA
authors: Sanders
authors: Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands. Electronic address: d.bogaert@umcutrecht.nl.
authors: Debby
authors: D
authors: Bogaert
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000276:immunology*; D014943:Global Health; D054884:Host-Pathogen Interactions / Q000276:immunology*; D006801:Humans; D007121:Immunocompetence; D015994:Incidence; D009426:Netherlands / Q000453:epidemiology; D011018:Pneumonia, Pneumococcal / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology*; D011159:Population Surveillance; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000276:immunology; D012307:Risk Factors; D013296:Streptococcus pneumoniae / Q000472:pathogenicity*