Killer cell immunoglobulin-like receptor genotypes and haplotypes with susceptibility to pulmonary tuberculosis infection.

BACKGROUND: Killer cell immunoglobulin-like receptors (KIRs) are expressed on natural killer (NK) cells and T cells and organized in highly polymorphic families. Genetic diversity is an important characteristic of KIR genes. The aim of the study was to investigate the influence of KIR genotypes and halotypes on the risk of pulmonary tuberculosis (PTB). METHODS: A sequence specific primer polymerase chain reaction (SSP-PCR) was employed to amplify the KIR genes and pseudogenes in 139 pulmonary tuberculosis (PTB) patients and 30 healthy controls. The innovative point of our study was the subdivision of the patient group according to sputum smear test (positive and negative). KIR genotype and haplotype frequencies were compared between the PTB group and the control group by Chi-square test, and p < 0.05 was regarded as statistically significant. RESULTS: The genotype AH and FZ14 may be associated with the clearance of Mycobacterium. In addition, haplotype B may be the susceptive haplotype that facilitated the clearance of Mycobacterium and haplotype A may be protective haplotype of PTB. CONCLUSIONS: Therefore, the diversity of genotypes and haplotypes induced an inflammatory reaction that resulted in continuous infection.

Elevated plasma level of HMGB1 is associated with disease activity and combined alterations with IFN-α and TNF-α in systemic lupus erythematosus.

Recent studies indicate that high-mobility group box protein 1 (HMGB1) contributes to the pathogenesis of diverse autoimmune disorders. It induces the production of interferon-alpha (IFN-alpha) and tumor necrosis factor alpha (TNF-alpha) in vitro. In the present study, plasma HMGB1, TNF-alpha, and IFN-alpha were determined with ELISA in 37 patients with systemic lupus erythematosus (SLE) and 39 age- and sex-matched healthy controls (HC). The possible associations of these cytokines with disease activities, autoantibodies, and certain laboratory parameters were also explored. The plasma levels of HMGB1, TNF-alpha, and IFN-alpha were increased in SLE patients compared with those of HC (P < 0.05). Moreover, the levels of HMGB1 and TNF-alpha in the active SLE patients were elevated compared with those in inactive patients and HC. Additionally, plasma HMGB1 was positively correlated with peripheral neutrophils, and plasma TNF-alpha was positively correlated with anti-Sm, ESR and CRP, while plasma IFN-alpha was inversely correlated with the age and platelet level in SLE patients. Our data indicated that increased plasma HMGB1 was associated with disease activity in SLE, which was similar to TNF-alpha. High level of plasma IFN-alpha may be related to nephritis and thrombocytopenia in SLE.

Interleukin-18 synergism with interleukin-2 in cytotoxicity and NKG2D expression of human natural killer cells.

Natural killer (NK) cells play an important role in anti-tumor immunity. Interleukin (IL)-18 is an immunoregulatory cytokine that induces potent NK cell-dependent anti-tumor responses when administrated with other cytokines. In this study, we explored the effects of combining IL-18 and IL-2 on NK cytotoxicity as well as expression levels of the NK cell receptor NKG2D in vitro. Freshly isolated PBMCs were incubated for 48 h with IL-18 and IL-2, then CD107a expression on CD3-CD56+ NK cells was determined by three-colour flow cytometry to evaluate the cytotoxicity of NK cells against human erythroleukemia K562 cells and human colon carcinoma HT29 cells. Flow cytometric analysis was also employed to determine NKG2D expression on NK cells. The combined use of IL-18 and IL-2 significantly increased CD107a expression on NK cells compared with using IL-18 or IL-2 alone, suggesting that the combination of these two cytokines exerted synergistic enhancement of NK cytotoxicity. IL-18 also enhanced NKG2D expression on NK cells when administered with IL-2. In addition, blockade of NKG2D signaling with NKG2D-blocking antibody attenuated the up-regulatory effect of combining IL-18 and IL-2 on NK cytolysis. Our data revealed that IL-18 synergized with IL-2 to dramatically enhance the cytolytic activity of human NK cells in a NKG2D-dependent manner. The results appear encouraging for the use of combined IL-18 and IL-2 in tumor immunotherapy.