ABSTRACT
ObjectiveTo investigate the association of the expression of the NK cell-activating receptor NKG2D, its ligand major histocompatibility complex class I chain-related gene A (MICA), and related cytokines ［interferon-γ (IFN-γ), interleukin-10 (IL-10), and interleukin-15 (IL-15)］ with intrahepatic inflammation in primary biliary cholangitis (PBC). MethodsLiver biopsy specimens were collected from 30 patients with PBC (PBC group), 15 patients with chronic hepatitis B (CHB group), and 10 patients with nonalcoholic fatty liver disease (NAFLD group), who were hospitalized in The Second Affiliated Hospital of Kunming Medical University from August 2014 to June 2015. The degree of liver inflammation (G) and fibrosis degree (S) of the liver specimens were determined, and immunohistochemistry was used to measure the expression of NKG2D, MICA, IFN-γ, IL-10, and IL-15 in liver tissue (the scores were determined based on the number of cells stained and the degree of staining to evaluate the expression of each marker). A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the t-test was used for comparison between two groups; a Spearman correlation analysis was used to investigate correlation. ResultsIn the PBC group, the expression of NKG2D increased with the degree of inflammation, and the patients with G3-4 inflammation had significantly higher expression than those with G1-2 inflammation (G1 vs G2 vs G3 vs G4: 1.4±0.05 vs 1.56±0.05 vs 1.86±0.11 vs 2.60±0.17, F=150.8, P＜0.05); the expression of NKG2D decreased with fibrosis degree (S3 vs S4: 2.30±0.17 vs 1.56±0.05, t=-1.52, P＜0.05). In the PBC group, there was no significant difference in MICA between G3 and G4 (0.11±0.01 vs 0.20±0.03, t=-2.20, P＞0.05) and between S3 and S4 (0.12±0.02 vs 0.18±0.03, t=-2.64, P＞0.05). In the PBC group, there was a significant difference in the expression of IL-15 between the patients with different degrees of inflammation (G1 vs G2 vs G3 vs G4: 0.70±0.10 vs 1.50±0.10 vs 1.93±0.11 vs 2.60±0.17, F=251.3, P＜0.05), while there was no significant difference between the patients with different fibrosis degrees (S3 vs S4: 2.00±0.05 vs 2.40±0.30, t=-1.62, P＞0.05). In the CHB group, there was a significant difference in the expression of IL-15 between the patients with different degrees of inflammation (G1 vs G2 vs G3: 0.73±0.15 vs 1.96±0.15 vs 2.50±0.17, F=150, P＜0.05) and between the patients with different fibrosis degrees (S1 vs S2 vs S3: 0.70±0.10 vs 21.96±0.15 vs 2.50±0.17, F=158.7, P＜0.05). In the PBC group, the expression of IL-10 was only observed in the patients with G1 inflammation (0.16±0.01), and in the CHB group, the expression of IL-10 was observed in the patients with G1 and G2 inflammation, with no significant difference (G1 vs G2: 0.19±0.01 vs 0.13±0.01, t=-1.522, P＞0.05). In the patients with PBC, the expression of IL-15 in liver tissue was positively correlated with the levels of alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (GGT) (r=0.241 and 0.407, P=0.014 and 0.045). ConclusionThe NK cell-activating receptor NKG2D affects the degree of intrahepatic inflammation in PBC, and the NKG2D ligand MICA is expressed in the advanced stage of PBC and can downregulate NKG2D. The expression of IL-15 increases with the degree of inflammation in PBC and is positively correlated with the levels of ALP and GGT, suggesting that the activation of NK cells and abnormal secretion of cytokines are involved in the development and progression of PBC and IL-15 may be used as an auxiliary index for the diagnosis of PBC.
ABSTRACT
Objective To investigate the function of major histocompatibility complex (MHC)class Ⅰ-related gene (MIC) in ulcerative colitis (UC) pathogenesis. Methods The difference of MICA, M ICB and their ligand NKG2D genes expression in colonic mucosa tissue of 34 UC patients and 12 healthy people were determined by fluorescent real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and the expression location of M ICA in colonic mucosa tissue was obtained by laser scanning confocal microscope. Results The mRNA level of MICA, MICB and NKG2D expression in UC groups (3. 5408±2. 6658, 8. 9879±3. 2893 and 2. 4395±0. 8147 accordingly) was significantly higher than that in the healthy controls ( 1. 0477 ± 0. 7201, 4. 6293 ± 1. 2616 and 1. 1624±0. 3954 accordingly) (P = 0.0053, 0.0039 and 0. 0078 accordingly). It suggested that MICA was expressed in colonic epithelia cell membranes by laser scanning confocal microscopy.Conclusion The mRNA level of MICA, M ICB, and their ligand, NKG2D expression were all up regulated in the colonic mucosa of UC patients, which indicated MIC gene might perform important local function in UC.
ABSTRACT
Although nickel hypersensitivity is known as a delayed-type hypersensitivity mediated by nickel-specific T cells, it is greatly influenced by other immune cells. Here we show that splenic natural killer cells (NK cells) directly or indirectly respond to nickel by secretion of IFN-gamma. Using enzyme-linked immunosorbent spot (ELISPOT) assays, we found that nickel-reactive cells readily secreted IFN-gamma when splenocytes were cultured in the presence of varying concentrations of nickel sulfate (NiSO4) for 24 h. However, nickel-reactive IL-2- or IL- 4-secreting cells were infrequent during the 24-h culture with NiSO4. Immune responses to nickel were innate, not adaptive, in nature since the frequency of nickel-reactive IFN-gamma-secreting cells did not increase upon previous exposure to NiSO4 and recombination activating gene (RAG)-1-deficient mice contained nickel-reactive IFN-gamma-secreting cells. The involvement of NK cells in the innate response to NiSO4 was confirmed since we could observe a significant reduction of the frequency of nickel-reactive cells in NK cell-depleted mice. Furthermore, the number of IFN-gamma secreting cells was significantly reduced in the ELISPOT assays when NKG2D was blocked by anti-NKG2D antibody. These results suggest that there is an early and rapid innate immune response to nickel, which is mediated by NK cells and the NKG2D receptor. The significance of the innate response to nickel is that it may contribute to development of the late T cell-mediated delayed type hypersensitivity against nickel.