الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 177 |  |  |
| | | from | 177 | | |
Abstract
Introduction: In developed countries, an inverse relationship had been noticed between an increasing prevalence of allergic and autoimmune diseases as rheumatoid arthritis (RA) and the improvement of hygiene procedures with the treatment of infectious diseases. Such relationship indicated that exposure to infectious diseases in early childhood could protect against the development of allergic and autoimmune diseases later on in life. Anti-arthritic effect of some protozoa was proved including Leishmania, and Trypanosoma brucei. Anti-autoimmune effect of malaria protozoa species have been tested as well. Plasmodium chabaudi was found to reduce the clinical evolution of experimental autoimmune encephalitis.Anti-arthritic outcomes have been reported by testing many helminths in animal models of CIA such as, Acanthocheilonema vitae, Ascaris suum, Heligomosomoides polygyrus, Schistosoma mansoni, Schistosoma japonicum and Hymenolepis diminuta. The Aim of this study: Immunomodulatory effects of parasitic infections on the outcomes of allergic or autoimmune disorders have been addressed in many experimental studies. We examined the effects of Plasmodium yoelii 17X NL (Py) and Fasciola hepatica gigantica (Fhg) infection on collagen- induced arthritis (CIA). Materials and methods: Male DBA/1J mice were immunized with bovine type II collagen (IIC). Py inoculation was induced at three different time points (1, 4 weeks after or 4 weeks before the immunization), while Fhg infection was done 4 weeks p.i.. Only the inoculation at 4 weeks after IIC immunization significantly inhibited arthritis development the same was with Fhg. Non- malarial anaemia induced by phenylhydrazine hydrochloride (PHZ) did not affect arthritis development. In the infected mice, anti- IIC IgG levels were transiently reduced. In addition, splenic production of pro- arthritic cytokines (IL- 17 and TNF- α) and IFN- γ decreased, whereas IL- 10 production increased. While in Fhg; IL- 17 and IL-4 increased, and TNF- α reduced. Flow cytometric analysis clarified that the main IL- 10 producers in Py- infected mice had the CD4 + CD25 – Foxp3 – phenotype, presumably Tr1 cells. Conclusion: We demonstrated that both experimental malarial and Fasciola infection alleviated autoimmune arthritis via immunomodulation, suggesting the importance of malaria and Fasciola in the hygiene hypothesis and the significance of searching for therapeutic immunomodulatory molecules from parasites.