Association of vitamin D levels and risk of latent tuberculosis in the hemodialysis population

BackgroundVitamin D is essential in the host defense against tuberculosis (TB). Suboptimal vitamin D status is common in the hemodialysis population. Hemodialysis patients have an increased risk compared to the general population latent tuberculosis infection (LTBI). However, the association between vitamin D deficiency and LTBI in this population remains unclear.Materials and methodsWe conducted a cross-sectional study between March and May 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-Tube was used to assess LTBI. Plasma 25-hydroxycholecalciferol (25-OHD) levels were measured by Elecsys Vitamin D Total assay. Suboptimal vitamin D levels included vitamin D insufficiency 20–29 ng/mg and vitamin D deficiency <20 ng/mL. Predictors for LTBI were analyzed.ResultsA total of 287 participants were enrolled. The suboptimal vitamin D level was 31.4% (90/287), which including the vitamin D deficiency was 13.9% (40/287). A total of 49.1% (141/287) people received nutritional vitamin D supplementation. The prevalence of IGRA positivity in this study was 25.1% (72/287). There was no significant difference in vitamin D concentrations or the proportion of vitamin D supplementation among the IGRA-positive and IGRA-negative groups (p = 0.789 and 0.496, respectively). In multivariate analysis, age >65 years old (odds ratio (OR), 1.89; 95% CI, 1.08–3.31; p = 0.026) and TB history (OR, 3.51; 95% CI, 1.38–8.91; p = 0.008) were independent predictors of IGRA positivity.ConclusionThis is the first study to report that vitamin D deficiency was not associated with IGRA positivity in a hemodialysis population. Aging and TB history were both independent predictors for LTBI.     

Gamma-interferon (IFN-gamma) augments apoptotic response to mistletoe lectin-II via upregulation of Fas/Fas L expression and caspase activation in human myeloid U937 cells

Mistletoe lectin-II, a major composition of Korean mistletoe (Viscum album coloratum), is known as a potent apoptosis inducer. The previous research has demonstrated that Korean mistletoe lectin-II induces apoptosis via c-Jun N terminal kinase (JNK) activation in human myeloid U937 cells. The purpose of this research is to prove the synergistic action of mistletoe lectin-II and interferon-γ (IFN-γ) in the apoptotic cytotoxicity of U937. When U937 cells were treated with mistletoe lectin-II after being differentiated by IFN-γ, the proteolytic activity of caspase-3 and 9 was markedly elevated and that of caspase-8 was prolonged for 18 hr. The activation of caspase-3-like protease requires the earlier cleavage of poly(ADP-ribose) polymerase(PARP). Caspase-1 was, however, not activated during the resting phase and nor in IFN-γ-differentiated U937 cells. Western blot analysis revealed that, in IFN-γ-differentiated U937 cells, the expression of Fas (CD95/APO-1) & Fas ligand(FasL) increases the apoptotic sensitivity against Mistletoe lectin-II. Fas (CD95/APO-1) & FasL were not significantly induced solely by mistletoe lectin-II. Furthermore the activity of JNK1 in U937 cells was also markedly increased with IFN-γ-differentiation, compared to that of the control. These results suggest that the IFN-γ-differentiation of U937 cells increases the susceptibility to mistletoe lectin-II-induced apoptosis.     

The effects of inflammatory cytokines on steroidogenic acute regulatory protein expression in macrophages

Objective: To investigate the expression of steroidogenic acute regulatory protein (StAR) in macrophages and the effects of inflammatory cytokines on StAR expression. Methods: The macrophages isolated from ApoE knockout mice and C57BL/6J mice and RAW264.7 cells (a cell line from mouse macrophage. ATCC Number: TIB-71^TM) were cultured in DMEM containing 10% fetal bovine serum. RAW264.7 cells were treated with different inflammatory cytokines (TNF-α, IFN-γ and TGF-β1) and 8-Br-cAMP, a cAMP analog. RT-PCR and Western blot analysis were applied to evaluate the effects of inflammatory cytokines on StAR expression. Results: RT-PCR and Western blot analysis demonstrated the expression of StAR in the macrophages isolated from ApoE knockout mice, C57BL/6J mice and RAW264.7 cells. Proinflammatory cytokines TNF-α and IFN-γ significantly decreased StAR mRNA and protein levels in RAW264.7 cells. The inhibition was dose- and time-dependent. In contrast, anti-inflammatory cytokine TGF-β1 increased StAR mRNA and protein levels. At 1:15 molecular ratio, TGF-β1 blocked the down-regulation of StAR expression mediated by TNF-α. cAMP also induced StAR expression in RAW264.7 cells. When the cells were co-treated with 8-Br-cAMP and TNF-α, 8-Br-cAMP failed to induce StAR expression. Conclusion: Our results provide interesting evidence that inflammatory cytokines regulate StAR expression in macrophages. Received 12 August 2006; returned for revision 28 September 2006; returned for final revision 28 May 2007; accepted by M. Katori 22 June 2007     

干扰素γ基因内含子1+874位点多态性与乙型肝炎病毒感染关系的研究

目的 研究干扰素γ（IFN-γ）基因内含子1＋874位点多态性与乙型肝炎病毒（HBV）感染、转归的关系,探讨慢性HBV感染的遗传易感因素.方法 采用序列特异性引物-聚合酶链反应（PCR-SSP）技术检测231例慢性HBV携带患者、165例自限性HBV感染者和135名正常对照者IFN-γ基因内含子1＋874位点T/A单核苷酸多态性.结果 慢性HBV感染组IFN-γ基因＋874位点AA基因型频率（TT、TA、AA频率分别为9.1%、12.1%、78.8%）高于正常对照组（TT、TA、AA频率分别为12.6%、23.0%、64.4%）（x2=9.60,P=0.008）;而自限性HBV感染组（TT、TA、AA频率分别为13.9%、23.7%、62.4%）和对照组之间差异无显著性（x2=0.16,P=0.92）.结论 IFN-γ基因内含子1＋874位点多态性与慢性HBV感染有关,该位点多态性可能在决定个体HBV感染遗传易感性方面有一定意义.     

充血性心力衰竭患者细胞免疫功能失调的探讨

目的探讨充血性心力衰竭(CHF)患者外周血辅助性T淋巴细胞功能失调及其在心力衰竭发生及发展中的意义。方法选择62例CHF患者作为研究组,其中,心功能Ⅱ级28例,Ⅲ级16例,Ⅳ级18例;30例健康志愿者作为对照组。采用流式细胞分析法,检测所有被检者外周血CD4 细胞胞内细胞因子干扰素γ(IFN-γ)和白细胞介素4(IL-4)的表达。同时分离外周血单个核细胞,经植物血凝素(PHA)刺激培养后,应用酶联免疫吸附方法(ELISA)检测培养上清液中IFN-γ和IL-4水平。结果CHF组患者IFN-γ染色阳性的细胞占CD4 T细胞的比率为17.48%,明显高于对照组的12.09%。IL-4染色阳性细胞比率两组间未见显著差异。ELISA检测显示心力衰竭组培养上清液中IFN-γ水平及IFN-γ/IL-4比值明显高于对照组,而两组间IL-4水平则无显著差异。结论心力衰竭患者辅助性T淋巴细胞功能与心功能之间有一定关系,辅助性T淋巴细胞功能失调可能参与了CHF患者的心室重构过程。     

苦参碱对刀豆蛋白A致小鼠肝损伤的保护作用

目的探讨苦参碱对刀豆蛋白 A(Con A)所致肝损伤的防治作用.方法 48只 NIH小鼠随机分为正常对照组、模型组、苦参碱 25 mg/kg组、苦参碱 12.5 mg/kg组和联苯双酯治疗组.除正常对照组外,其他组于实验首日静脉注射 Con A 20 mg/kg,苦参碱两个剂量组均采用尾静脉注射给药,联苯双酯组按 150 mg/kg灌胃口服,每天 1次,连续 3 d,末次给药后 4 h,再次静脉注射 Con A 20 mg/kg,8 h后检测血浆 ALT活性及 IFN-γ和 TNF-α含量,观察肝组织病理学变化.结果苦参碱 25 mg/kg组、12.5 mg/kg组小鼠 ALT活性及 IFN-γ和 TNF-α含量均明显低于模型组,有显著性差异(P<0.01);苦参碱两个剂量组肝脏病理改变明显减轻.结论苦参碱对 Con A所致小鼠肝损伤具有较好的防治作用,抑制 T淋巴细胞活化和 IFN-γ、TNF-α的释放可能是其主要的作用机制.     

结核病患者外周血γ干扰素释放试验假阴性的相关因素分析

目的 分析影响结核病患者外周血γ干扰素释放试验(interferon-gamma release assay,IGRA)检测假阴性的影响因素。方法 回顾性分析2018年1月至2020年3月解放军总医院第八医学中心结核四科收治的资料完整、外周血IGRA检测阴性和阳性的结核病患者,分别作为IGRA假阴性组(38例)和IGRA阳性组(119例),收集其一般情况、病史特点、血清生化指标和外周血淋巴细胞亚群,采用单因素和多因素logistic回归分析导致IGRA检测结果假阴性的影响因素。结果 IGRA假阴性组淋巴细胞计数、T细胞计数、CD4⁺T细胞计数、CD8⁺T细胞计数、NKT细胞计数M(Q₁,Q₃)分别为1.15(0.77,1.58)×10⁹个/L、867.50(508.75,1135.50)个/μl、493.00(256.00,673.75)个/μl、254.50(170.25,429.25)个/μl、38.50(16.50,88.25)个/μl,均明显低于IGRA阳性组[分别为1.46(0.99,1.88)×10⁹个/L、1013.00(667.00,1394.00)个/μl、590.00(386.00,850.00)个/μl、335.00(232.00,561.00)个/μl、57.00(30.00,121.00)个/μl,差异均有统计学意义(Z值分别为-2.512、-2.143、-2.092、-2.303、-2.338,P值分别为0.012、0.032、0.036、0.021、0.019)。logistic回归分析结果显示,NKT细胞计数低于正常值(<40个/μl)的患者,IGRA检测出现假阴性的风险是NKT细胞计数正常者的2.440倍(95%CI:1.159~5.134)。结论 NKT细胞计数的减少可能导致外周血IGRA出现假阴性。     

Performance evaluation of newly developed fluorescence immunoassay-based interferon-gamma release assay for the diagnosis of latent tuberculosis infection in healthcare workers

The ichroma? IGRA-TB (Boditech Med Inc., Chuncheon, Republic of Korea) is an automated fluorescent immunoassay-based point-of-care interferon-gamma release assay for detecting latent tuberculosis infection. We evaluated this assay with 408 health care workers, and demonstrated its acceptable performances comparing to QuantiFERON-TB Gold-Plus (QFT-Plus; Qiagen, Germantown, MD).     

Assay of pleural fluid interleukin-6, tumour necrosis factor-alpha and interferon-gamma in the diagnosis and outcome correlation of tuberculous effusion

OBJECTIVE: To assess the usefulness of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in the diagnosis and prediction of outcome of pleural tuberculosis. PATIENTS AND METHODS: Pleural fluid from 32 TB and 34 non-TB patients was sent for assay of IL-6, TNF-alpha and IFN-gamma. Clinical parameters at presentation and residual pleural scarring at completion of treatment were assessed for pleural TB cases. RESULTS: The pleural fluid Levels of IL-6, TNF-alpha and IFN-gamma in TB patients were significantly higher than those with non-TB effusions (P values of <0.001, 0.018 and <0.001, respectively by independent t-test). Utility of these cytokines for diagnosis of pleural TB was evaluated using receiver operating characteristic (ROC) curve analysis. The cut-off values for IL-6, TNF-alpha and IFN-gamma determined in this analysis were 4000, 4 and 60 pg/ml respectively, and their sensitivity and specificity were 90.6% and 76.5%, 90.6% and 79.4%, 100% and 100%, respectively. The pretreatment pleural fluid IL-6 levels had a positive correlation with the number of febrile days after treatment (Pearson correlation test: r=0.60, P=0.009). A negative correlation was found between the percentage reduction in pleural fluid cytokines after 2 weeks treatment and the extent of residual pleural scarring (IL-6: r=-0.62, P=0.041; TNF-alpha: r=-0.65, P=0.030; IFN-gamma: r=0.83, P=0.002). CONCLUSION: Pleural fluid IL-6, TNF-alpha and IFN-gamma assays are useful in the diagnosis of pleural TB. The initial IL-6 level correlates with the number of febrile days. The percentage change of cytokines after 2 weeks of treatment also helps to predict residual pleural scarring.     

Peripheral virus-specific T-cell interleukin-10 responses develop early in acute hepatitis C infection and become dominant in chronic hepatitis

BACKGROUND /AIMS: Interleukin-10 (IL-10) has been ascribed pro-viral but anti-fibrotic properties in chronic hepatitis C virus (HCV) infection. In this study, we examined the role of HCV-specific T-cell IL-10 response in patients with acute and chronic HCV infection. METHODS: Peripheral HCV-specific T-cell IL-10 and IFNgamma responses were measured in cytokine Elispot assay using overlapping HCV-derived peptides in patients with chronic (n=61), resolved (n=15) and acute (n=8) hepatitis C, looking for their onset, quantity, breadth and durability relative to clinical and virological outcomes. The source and effect of HCV-specific IL-10 response were determined in depletion and IL-10 neutralization experiments. RESULTS: Both HCV-specific IL-10 and IFNgamma responses were detected early within 1-2 months of acute clinical hepatitis C. However, only HCV-specific IL-10 response correlated with elevated liver enzymes, increased viremia and suppressed HCV-specific CD4(+) T-cell proliferation in acute infection. While these associations were lost in established chronic infection, HCV-specific IL-10 responses were increased in patients without cirrhosis while IL-10 blockade enhanced antiviral effector IFNgamma responses. CONCLUSIONS: HCV-specific IL-10 Tr1 responses may play a dual role in HCV infection, dampening effector T-cells to promote viral persistence in acute infection but also protecting against progressive fibrosis in chronic infection.