The hygiene hypothesis has been implicated in the dramatic increase in autoimmune and allergic diseases noticed in recent decades, especially in developed countries. This growth was associated with lesser exposure to diverse immunoregulatory infectious agents. This hypothesis has been proved by many potent epidemiological and experimental studies. The results of these studies along with the analysis of the western world's microbiome helped us to have a greater idea about microorganisms shared in the hygiene hypothesis, as well as their main mechanisms that have an effect on the immune system. Protozoal infections have been proved to have remarkable immunomodulatory changes in different autoimmune diseases. Helminths and their derivatives were proved to have a protective role. Helminths' broad immunomodulatory effects have been tested in clinical trials of autoimmune diseases, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and type-1 diabetes. In this review, we discussed particular parasitic infections and their immunomodulatory effects on some autoimmune diseases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.