[Regulatory role of NKT cells in the prevention of type 1 diabetes]

T regulatory and Th17 cells in chronic rhinosinusitis with polyps

BACKGROUND

Chronic rhinosinusitis (CRS) is categorized into 2 types based on the absence (CRSsNP) and presence of nasal polyps (CRSwNP). Although CRSsNP patients lack nasal polyps, the mucosa may show variable degrees of polypoid change. This raises the question of whether or not the classification system is an over simplification and that CRSsNP and CRSwNP only represent 2 phenotypic extremes along a broader spectrum of immunologically different disease processes. To investigate this, adaptive and innate immune cells were compared in the different tissue types within CRSsNP and CRSwNP patients.

METHODS

Tissue from 15 CRSwNP, 6 CRSsNP, and 8 healthy control patients was obtained prospectively. Nonpolypoid mucosa, polypoid tissues, and polyps were obtained at the time of endoscopic sinus surgery and analyzed using flow cytometry for various adaptive and innate immune cell subsets.

RESULTS

In the polyps from CRSwNP patients there were significantly more T regulatory (Treg) cells (12.86 ± 12.60 vs 2.83 ± 4.68) and Th17 cells (16.12 ± 11.75 vs 2.31 ± 2.13) compared to the polypoid tissue from CRSsNP patients. Cellular infiltrates in the nonpolypoid or polypoid mucosa of the different patient categories showed no difference in CRSwNP, CRSsNP and control groups.

CONCLUSION

This observational study identified an increase in Treg and Th17 cells in CRSwNP patients implying that these cells may be implicated in polyp development. Importantly it also identified a similar inflammatory infiltrate in nonpolyp or polypoid mucosa across control, CRSsNP, and CRSwNP groups inferring that polyps should be sampled when studying CRSwNP.

Unmet needs in autoimmunity and potential new tools

The term "autoimmunity" refers to a pathological condition in which the immunological tolerance of self-antigens is broken through, cross-reactive T cells are activated, and autoantibodies are produced by B cells. The intricate interplay among those aberrantly activated immune cells as well as inflammatory cytokines secreted by them contributes to the development of proinflammatory cascade which eventually leads to the occurrence of autoimmune diseases (AIDs) and organ damage. Autoimmune diseases occupy a broad spectrum of human diseases with more than 70 different disorders and afflict approximately 5-8 % of the world's population. AIDs can be categorized into organ-specific and systemic. Although the exact mechanism of AIDs remains elusive, it is generally believed that both genetic polymorphism and environmental exposure are involved in the development of AIDs. Aberrant epigenetic marks are also identified in patients with AIDs. In addition, dysregulation of innate immune system and molecular mimicry are indicated to play important roles in the initiation and maintenance of autoreactive inflammation. Based on the progress made in elucidating molecular mechanisms underlying AIDs, novel biomarkers for prediction, early diagnosis, prognosis and treatment response, and therapeutic strategies are proposed, which represents a promising future in the battle against AIDs. However, challenges remain regarding the clinical application of these potential new tools.

A gluten-free diet lowers NKG2D and ligand expression in BALB/c and non-obese diabetic (NOD) mice

The interplay between diet and immune parameters which could affect type 1 diabetes (T1D) pathogenesis is not sufficiently clarified. Intestinal up-regulation of the activating receptor natural killer group 2D (NKG2D) (CD314) and its ligands is a hallmark of coeliac disease. However, the direct effect of gluten on NKG2D expression is not known. We studied, by fluorescence activated cell sorter (lymphoid tissues) and reverse transcription–quantitative polymerase chain reaction (intestine and pancreatic islets), if a gluten-free diet (GF diet) from 4 weeks of age or a gluten-free diet introduced in breeding pairs (SGF diet), induced changes in NKG2D expression on DX5⁺(CD49b) natural killer (NK) cells, CD8⁺ T cells and in intestinal and islet levels of NKG2D and ligands in BALB/c and non-obese diabetic (NOD) mice. Gluten-free NOD mice had lower insulitis (P < 0·0001); reduced expression of NKG2D on DX5⁺ NK cells in spleen and auricular lymph nodes (P < 0·05); and on CD8⁺ T cells in pancreas-associated lymph nodes (P = 0·04). Moreover, the level of CD71 on DX5⁺ NK cells and CD8⁺ T cells (P < 0·005) was markedly reduced. GF and SGF mice had reduced expression of NKG2D and DX5 mRNA in intestine (P < 0·05). Differences in intestinal mRNA expression were found in mice at 8, 13 and 20 weeks. Intestinal expression of NKG2D ligands was reduced in SGF mice with lower expression of all ligands. In isolated islets, a SGF diet induced a higher expression of specific NKG2D ligands. Our data show that a gluten-free diet reduces the level of NKG2D and the expression of NKG2D ligands. These immunological changes may contribute to the lower T1D incidence associated with a gluten-free diet.

OCH ameliorates bone marrow failure in mice via downregulation of T-bet expression

The aim of this study is to evaluate the immune mechanism of OCH in the treatment of AA (also named bone marrow failure, BMF) induced in mice. OCH at a dose of 400 μg/kg was injected intraperitoneally (I.P.) prior to the induction of BMF. Our study showed that the incidence of BMF was 100% in BMF group and 13% in OCH treatment group. Significant higher level of IL-4 and lower level of IFN-γ were observed in OCH group than that in BMF group (P < 0.05) as well as untreated group over BMF (P < 0.05). However, there was no significant difference between OCH and untreated group. Compared with untreated, the expression level of T-bet in OCH and BMF was all significantly higher. However, T-bet expression level was lower in OCH than in BMF. In addition, OCH treatment increased NKT cell fractions of bone marrow and the colonies of CFU-GM. In conclusion, treatment of OCH prior to the induction of BMF could prevent the incidence of BMF possibly through downregulating T-bet expression leading to the transition of immune response from Th1 to Th2, suggesting OCH might be a new therapeutic approach in the treatment of BMF or AA.