title: Parasitic infections and immune function: effect of helminth infections in a malaria endemic area.
abstract: According to the hygiene hypothesis, reduced exposure to infections could explain the rise of atopic diseases in high-income countries. Helminths are hypothesised to alter the host's immune response in order to avoid elimination and, as a consequence, also reduce the host responsiveness to potential allergens. To elucidate the effect of current helminth infections on immune responsiveness in humans, we measured cytokine production in a rural Ghanaian population in an area with multiple endemic parasites including malaria, intestinal helminths and protozoa. Multiplex real-time PCR in stool samples was used for the detection of four gastrointestinal helminths, of which only Necator americanus was commonly present. A similar assay was used to test for Giardia lamblia in stool samples and malaria infection in venous blood samples. Levels of the cytokines interleukin (IL)-10, tumour necrosis factor (TNF)-α, IL-17, IL-6, IL-13, and interferon (IFN)-γ were determined in whole-blood samples ex vivo-stimulated either with lipopolysaccharide (LPS) and zymosan (for innate cytokine production) or the T-cell mitogen phytohaemagglutinin (PHA). There were no significant differences in either innate or PHA-stimulated cytokine production dependent on current N. americanus infection. Plasmodium falciparum malarial infection was associated with a pro-inflammatory response indicated by increased innate production of TNF-α, IL-17 and IL-6. There was no clear pattern in cytokine responses dependent on G. lamblia-infection. In conclusion, in this rural Ghanaian population current N. americanus infections are not associated with altered immune function, while infection with P. falciparum is associated with pro-inflammatory innate immune responses.
authors.affiliation: Department of Gerontology and Geriatrics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Anna G C
authors.initials: AG
authors.lastname: Boef
authors.forename: Linda
authors.initials: L
authors.lastname: May
authors.forename: David
authors.initials: D
authors.lastname: van Bodegom
authors.forename: Lisette
authors.initials: L
authors.lastname: van Lieshout
authors.forename: Jaco J
authors.initials: JJ
authors.lastname: Verweij
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Maier
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: Ulrika K
authors.initials: UK
authors.lastname: Eriksson
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D060085:Coinfection; D016207:Cytokines / Q000097:blood / Q000276:immunology; D019353:Endemic Diseases; D005243:Feces / Q000382:microbiology / Q000469:parasitology; D005260:Female; D005869:Ghana / Q000453:epidemiology; D016829:Giardia lamblia / Q000276:immunology; D005873:Giardiasis / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology; D006373:Helminthiasis / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology; D006801:Humans; D007113:Immunity, Innate; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D017221:Necator americanus / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology; D012424:Rural Population
chemical_list: D016207:Cytokines