title: Evidence that scabies mites (Acari: Sarcoptidae) influence production of interleukin-10 and the function of T-regulatory cells (Tr1) in humans.
abstract: We performed experiments to determine whether an extract of Sarcoptes scabiei (De Geer) influenced cytokine expression by human T-lymphocytes. Peripheral blood mononuclear cells from five sensitized donors and four donors without sensitization to scabies mites were challenged with a T-cell mitogen alone, with scabies extract (SS) alone, or with mitogen and SS together. Supernatants were analyzed for the cytokines interferon-gamma (IFNgamma), interleukin (IL)-2, IL-4, and IL-10. No IL-2 or IL-4 was produced in response to scabies extract. Cells from both naive and sensitized donors produced large amounts of IFNgamma and IL-10. The lack of IL-4 but high levels of IL-10 suggests that IL-10 was likely secreted by type 1 T-regulatory cells, which were activated by something in the scabies extract. IL-10 has anti-inflammatory and immune-suppressive effects. It may play a key role in depressing the inflammatory and immune responses in humans so that clinical symptoms are not seen until 4-6 wk after a person becomes infested with scabies mites.
authors.affiliation: Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.
authors.forename: Larry G
authors.initials: LG
authors.lastname: Arlian
authors.forename: Marjorie S
authors.initials: MS
authors.lastname: Morgan
authors.forename: Cassandra C
authors.initials: CC
authors.lastname: Paul
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000096:biosynthesis*; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008924:Mite Infestations / Q000276:immunology* / Q000469:parasitology; D012520:Sarcoptes scabiei / Q000737:chemistry*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D007376:Interleukin-2; D014020:Tissue Extracts; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma