title: Cytokine and chemokine responses to helminth and protozoan parasites and to fungus and mite allergens in neonates, children, adults, and the elderly.
abstract: BACKGROUND
  In rural sub-Saharan Africa, endemic populations are often infected concurrently with several intestinal and intravascular helminth and protozoan parasites. A specific, balanced and, to an extent, protective immunity will develop over time in response to repeated parasite encounters, with immune responses initially being poorly adapted and non-protective. The cellular production of pro-inflammatory and regulatory cytokines and chemokines in response to helminth, protozoan antigens and ubiquitous allergens were studied in neonates, children, adults and the elderly.
  
  
  RESULTS
  In children schistosomiasis prevailed (33%) while hookworm and Entamoeba histolytica/E. dispar was found in up to half of adults and the elderly. Mansonella perstans filariasis was only present in adults (24%) and the elderly (25%). Two or more parasite infections were diagnosed in 41% of children, while such polyparasitism was present in 34% and 38% of adults and the elderly. Cytokine and chemokine production was distinctively inducible by parasite antigens; pro-inflammatory Th2-type cytokine IL-19 was activated by Entamoeba and Ascaris antigens, being low in neonates and children while IL-19 production enhanced "stepwise" in adults and elderly. In contrast, highest production of MIP-1delta/CCL15 was present in neonates and children and inducible by Entamoeba-specific antigens only. Adults and the elderly had enhanced regulatory IL-27 cytokine responses, with Th2-type chemokines (MCP-4/CCL13, Eotaxin-2/CCL24) and cytokines (IL-33) being notably inducible by helminth- and Entamoeba-specific antigens and fungus-derived allergens. The lower cellular responsiveness in neonates and children highlighted the development of a parasite-specific cellular response profile in response to repeated episodes of exposure and re-infection.
  
  
  CONCLUSIONS
  Following repeated exposure to parasites, and as a consequence of host inability to prevent or eliminate intestinal helminth or protozoa infections, a repertoire of immune responses will evolve with lessened pro-inflammatory and pronounced regulatory cytokines and chemokines; this is required for partial parasite control as well as for preventing inadequate and excessive host tissue and organ damage.
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Lechner
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Komander
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Hegewald
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.
authors.forename: Xiangsheng
authors.initials: X
authors.lastname: Huang
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.|Onchocerciasis Reference Laboratory, Institut National d'Hygiène, Sokodé, Togo.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Gantin
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.|Onchocerciasis Reference Laboratory, Institut National d'Hygiène, Sokodé, Togo.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Soboslay
authors.affiliation: Centre Hospitalier Universitaire Campus de Lomé, Université de Lomé, Lomé, Togo.
authors.forename: Abram
authors.initials: A
authors.lastname: Agossou
authors.affiliation: Centre Hospitalier Régional, Service Pédiatrie, Sokodé, Togo.
authors.forename: Meba
authors.initials: M
authors.lastname: Banla
authors.affiliation: Institute for Tropical Medicine, Eberhard Karls Universität Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Köhler