title: Cytokine networks in destructive periodontal disease.
abstract: BACKGROUND
  Cytokines are important regulatory proteins, produced by activated cells, which act by binding high affinity cell surface receptors. They are involved in almost all aspects of cell biology and form interacting networks, with cascades of sequential cell activation. They often show overlapping activities (redundancy) or the same cytokine may have a variety of different effects (pleiotropy). In excess, certain cytokines are damaging and proinflammatory. Tumour necrosis factor alpha (TNF alpha) and interleukin-I (IL-I) are markedly proinflammatory, inducing bone resorption, collagenase and prostaglandin E2 production.
  
  
  OBJECTIVE
  This paper focuses on the role of TNF alpha and IL-I in the cytokine networks of destructive chronic periodontitis; specifically their regulation by T cell cytokines, receptor antagonists and inhibitory soluble forms of the IL-I and TNF receptors.
  
  
  CONCLUSIONS
  A hypothesis is proposed that destructive periodontal disease may be due to disregulation of these inhibitors, rather than an overproduction of IL-I and TNF alpha per se.
authors.affiliation: Department of Oral Pathology, The London Hospital Medical College, UK.
authors.forename: G L
authors.initials: GL
authors.lastname: Howells
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology / Q000378:metabolism; D000818:Animals; D002908:Chronic Disease; D016207:Cytokines / Q000096:biosynthesis / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000502:physiology*; D010518:Periodontitis / Q000209:etiology* / Q000378:metabolism*; D018121:Receptors, Cytokine / Q000037:antagonists & inhibitors; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors / Q000502:physiology; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D018121:Receptors, Cytokine; D017472:Receptors, Interleukin-1; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha