Chronic helminth infections are often associated with a reduced prevalence of inflammatory disorders, including allergic diseases.
Helminths influence the immune system by downregulating T-cell responses and IL-10 appears to play a central role in this process.
Over the last decade, evidence has emerged for a new regulatory cell type, in addition to the well-known T regs: IL-10-producing B cells (regulatory B cells).
Initially, regulatory B cells were described in autoimmunity models where they decrease inflammation. Patients suffering from autoimmunity have an impaired regulatory B-cell function. They were also found in several helminth infection models.
Helminth-induced regulatory B cells suppress allergic inflammation and may open a new avenue for the treatment of inflammatory diseases, such as allergic asthma.
Regulatory T cells - 6 groups have been described (click to enlarge the image).
Regulatory B-cell induction by helminths: Implications for allergic disease. Hussaarts L, van der Vlugt LE, Yazdanbakhsh M, Smits HH. J Allergy Clin Immunol. 2011 Jun 17.
Image source: Trichuris egg in stool sample (40x). Wikipedia, GNU Free Documentation License, Version 1.2.