Regulatory T Cells in children with intestinal parasite infection

Abstract

Chronic intestinal parasite infection can induce both persistent immune activation and defective responsiveness of T cells. This study aimed to assess the number and function of T regulatory (Treg) cells in children with intestinal parasite infection. We have studied the peripheral blood from 93 children, 53 of them parasitized with protozoa, helminths, or both; the remainder were non parasitized, healthy controls. The number and function of CD4(+) CD25(high) and CD4(+) Foxp3(+) cells were similar in parasitized and control children. In contrast, there was a significant increase in the levels of CD3(+) CD69(+), CD4(+) CTLA-4(+), and CD8(+) CD28(-) T cells in helminth infected children. Moreover, some of these patients showed a diminished response to CD3/CD28 stimulation in comparison with the control children. Our data strongly suggest that whilst Treg cells are not affected by intestinal parasite infection, CD3(+) CD69(+), CD4(+) CTLA-4(+) and CD8(+) CD28(-) lymphocytes may play an important, but as yet undetermined role in the diminished immune competence observed in parasitized children.

Quantitative and functional analysis of CD69+ NKG2D+ T regulatory cells in healthy subjects

“…The suppressive activity of these cells is mainly mediated by TGF-b and IL-10, their differentiation is not dependent of Foxp3, and these cells show a variable expression of CD25 [32]. In this regard, it is of interest that the peripheral blood of patients with systemic lupus erythematosus show low levels of CD4 + CD69 + cells [32], and similar results have been observed in patients with renal allografts and children with intestinal parasite infection [33]. In contrast, patients with hepatocellular carcinoma show increased levels of CD4 + CD69 + CD25 À cells, which correlate with tumor size or the presence of metastases [15].…”

Regulatory T Cells in Infection

“…In areas hyperendemic for the intestinal helminth infections Ascaris lumbricoides and Trichuris suum, lymphocytes from infected children constitutively express high levels of IL-10 and TGF-b, while antigen-specific responses are inversely depressed (Turner et al, 2008). For example, CD4 þ CTLA4 þ T cells are more numerous in children with intestinal helminths than uninfected subjects (García-Hernández et al, 2009). Functionally, peripheral T cells from geohelminth-infected children show depressed in vitro immune responses to malarial and mycobacterial antigens that are rescued by removal of the CD25 high cells (Wammes et al, 2010).…”

Helminth Infections and Host Immune Regulation

“…ϩ CTLA-4 ϩ T cells (95). Thus, an immunoregulated state is a common outcome across a diverse range of helminth infections.…”