Immunogenetics of autoimmune thyroid diseases: A comprehensive review

Both environmental and genetic triggers factor into the etiology of autoimmune thyroid disease (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT). Although the exact pathogenesis and causative interaction between environment and genes are unknown, GD and HT share similar immune-mediated mechanisms of disease. They both are characterized by the production of thyroid autoantibodies and by thyroidal lymphocytic infiltration, despite being clinically distinct entities with thyrotoxicosis in GD and hypothyroidism in HT. Family and population studies confirm the strong genetic influence and inheritability in the development of AITD. AITD susceptibility genes can be categorized as either thyroid specific (Tg, TSHR) or immune-modulating (FOXP3, CD25, CD40, CTLA-4, HLA), with HLA-DR3 carrying the highest risk. Of the AITD susceptibility genes, FOXP3 and CD25 play critical roles in the establishment of peripheral tolerance while CD40, CTLA-4, and the HLA genes are pivotal for T lymphocyte activation and antigen presentation. Polymorphisms in these immune-modulating genes, in particular, significantly contribute to the predisposition for GD, HT and, unsurprisingly, other autoimmune diseases. Emerging evidence suggests that single nucleotide polymorphisms (SNPs) in the immunoregulatory genes may functionally hinder the proper development of central and peripheral tolerance and alter T cell interactions with antigen presenting cells (APCs) in the immunological synapse. Thus, susceptibility genes for AITD contribute directly to the key mechanism underlying the development of organ-specific autoimmunity, namely the breakdown in self-tolerance. Here we review the major immune-modulating genes that are associated with AITD and their potential functional effects on thyroidal immune dysregulation.     

地高辛标记布氏杆菌544ADNA探针的制备及其应用

作者应用自构键的ｐＢＣ_４重组质粒，经Ｋｐｎｌ和ＢａｍＨ_１双酶切回收０．２２ｋｂ的Ｂｒ．ａｂｏｒｔｕｓ５４４ＡＤＮＡ片段，将此片段纯化后采用地高辛标记方法制备探针。点杂交结果表明：此探针检测布氏杆菌ＤＮＡ的灵敏度达５ｐｇ，对中国１９型布氏杆菌ＤＮＡ杂交出现强的杂交信号而对５种革兰氏阴性菌ＤＮＡ以及人白细胞ＤＮＡ没有产生杂交反应，具有特异性强、敏感性高、简便易行等特点。为进一步用于实验室诊断人、畜布氏杆菌病和流行病学的调查提供了有效的手段。     

熊去氧胆酸联合非诺贝特治疗胆汁性肝硬化的疗效观察

目的：评价熊去氧胆酸（UDCA）联合非诺贝特对UDCA反应不佳的胆汁性肝硬化（PBC）患者的疗效。方法选择熊去氧胆酸治疗1年疗效不佳的PBC患者14例,给予UDCA 15 mg/（kg＆#183;d）,加非诺贝特0.16 g口服,治疗3个月。观察治疗前后患者症状、体征和肝功能生化指标的变化。结果治疗3个月后,71.4%（10/14）的PBC患者乏力症状明显减轻,57.1%（8/14）的患者皮肤瘙痒缓解,85.7%（12/14）的患者腹胀减轻,71.4%（10/14）的患者尿色变浅。治疗后较治疗前总胆红素[（43.1±19.6）μmol/L vs.（65.3±21.5）μmol/L]、直接胆红素[（38.3±11.0）μmol/L vs.（49.6±15.3）μmol/L]、总胆固醇[（5.36±1.82）mmol/L vs.（8.63±1.58）mmol/L]、γ-谷氨酰转肽酶[（155.6±86.3）U/L vs.（421.3±123.4） U/L]、碱性磷酸酶[（196.2±101.5）U/L vs.（395.1±156.3）U/L]、丙氨酸氨基转移酶[（42.5±18.9）U/L vs.（58.3±23.8）U/L]、天冬氨酸氨基转移酶[（40.3±25.6）U/L vs.（53.3±23.7）U/L]明显下降（P均〈0.05）;胆碱酯酶及白蛋白较前有上升,但差异无统计学意义（P 〉0.05）。结论对UDCA疗效不佳的PBC患者,UDCA联合非诺贝特可能有效改善患者的症状、体征及肝功能生化指标。     

The effect of ursodeoxycholic acid therapy on the natural course of primary biliary cirrhosis

BACKGROUND AND AIMS: We used a multistate modeling approach to assess the effect of ursodeoxycholic acid (UDCA) therapy on the natural course of primary biliary cirrhosis (PBC), which remains controversial. METHODS: Our population included 262 patients with PBC who had received 13-15 mg/kg UDCA daily for a mean of 8 years (range, 1-22 years). Data were analyzed using a multistate Markov model, with histologic stage progression, death, and orthotopic liver transplantation (OLT) as main end points. Survival without OLT was compared with that predicted by the updated Mayo model and with the expected survival in the control population. RESULTS: Forty-five patients developed cirrhosis, 20 underwent OLT, and 16 died by the censor date. Ten deaths were due to liver disease. The overall survival rates were 92% at 10 years and 82% at 20 years. Survival rates without OLT were 84% and 66% at 10 and 20 years, respectively, which were slightly lower than the survival rate of an age- and sex-matched control population (relative risk [RR], 1.4; P = .1) but better than the spontaneous survival rate as predicted by the updated Mayo model (RR, .5; P < .01). The survival rate of patients in stage 1 and 2 was similar to that in the control population (RR, .8; P = .5), whereas the probability of death or OLT remained significantly increased in treated patients in late histologic stages (RR, 2.2; P < .05). CONCLUSIONS: Treatment with UDCA alone normalizes the survival rate of patients with PBC when given at early stages. However, there is a continued need for new therapeutic options in patients with advanced disease.     

新型的抗线粒体抗体M2亚型抗体的检测方法在原发性胆汁性肝硬化诊断中的可靠性分析

目的研究以天然M2抗原和BPO融合蛋白M2-3E（BPO）为靶抗原的ELISA法（抗-M2-3EELISA）检测抗线粒体抗体M2亚型（AMA-M2）抗体在原发性胆汁化肝硬化（PBC）诊断中的可靠性。方法分别用间接免疫荧光法（IFL）、以丙酮酸脱氢酶复合体（PDC）为靶抗原的ELISA法（抗-PDCELISA）、以三联体（BPO）为靶抗原的ELISA法（抗-3EELISA）、以天然M2抗原和BPO融合蛋白M2-3E（BPO）为靶抗原的ELISA法（抗-M2-3EELISA）检测107例PBC、167例疾病对照和30例正常对照血清中的AMA-M2抗体。结果107例PBC患者用抗-M2-3EELISA、抗-3EELISA、抗-PDCELISA和IFL4种方法检测AMA-M2的检出率（敏感性）分别为99/107（92.5%）、94/107（87.9%）、78/107（72.9%）、87/107（81.3%）,特异性分别为97.3%、98.5%、98.5%、97.3%。抗-M2-3EELISA法AMA-M2的检出率（92.5%）显著高于抗-PDCELISA法（72.9%）（P〈0.001）、IFL法（81.3%,P〈0.001）,高于抗-3EELISA（87．9％）。在20例IFL检测AMA—M2为阴性的PBC患者中,用抗-M2—3EELISA法AMA—M2的检出率为11／20（55％）。抗-M2-3EELISA和IFL的重叠度为85．0％（91／107）。结论抗-M2-3EELISA法具有比IFL、抗-PDCELISA法和抗-3EELISA更高的敏感性,特异性达97-3％。因此,抗-M2-3EELISA法可作为第一轮AMA-M2的筛查,但不可以单独用于诊断PBC的标记。     

Distinct from its canonical effects,deletion of IL-12p40 induces cholangitis and fibrosis in interleukin-2Rα−/− mice

The IL-12 family modulates T cell mediated autoimmune diseases and GWAS in PBC have suggested a critical role of IL-12 and its subunits in modulating portal inflammation. We have taken advantage of an aggressive model of portal inflammation and colitis in IL-2Rα^−/− mice to study the specific role of IL-12 and, in particular, the immunobiology of p40^−/−IL-2Rα^−/− mice. Colonies of IL-2Rα^+/−, IL-2Rα^−/− and p40^−/−IL-2Rα^−/− mice were studied for the natural history of immunopathology in liver and colon using histology and immunohistochemistry. Further, to focus on mechanisms, liver, spleen and mesenteric lymph node flow cytometry was employed to identify specific phenotypes; cytokine analysis on inflammatory cell populations was compared between groups. Finally, Real-Time PCR was used to focus on the genes involved in hepatic fibrosis. Surprisingly, p40^−/−IL-2Rα^−/− mice manifest more severe portal inflammation and bile duct damage, including signs of portal hypertension and liver fibrosis, but a significant reduction in colitis. Indeed, p40^−/−IL-2Rα^−/− mice reveal a profound hepatic CD8⁺ T cell infiltrate, whose major component are effector memory cells as well as enhanced hepatic Th1 but reduced Th17 responses. These observations were confirmed by Real-Time PCR analysis of fibrosis-related genes in the liver. Distinct from its canonical effects, IL-12p40 plays a critical role in autoimmune cholangitis, including hepatic fibrosis. These data take on striking significance for any proposed human trials that modulate the IL-12p40 pathway in human PBC.     

Serum markers of infections in patients with primary biliary cirrhosis: evidence of infection burden

Background

Currently not much is known regarding the environmental factors involved in primary biliary cirrhosis (PBC). It is even more unclear which factors may determine the subgroup (i.e., AMA status) of patients with PBC. We thus tested AMA + and AMA − PBC patients' sera for antibodies (Abs) against multiple infectious agents.

Methods

Sera from 69 patients with PBC (49 AMA + and 20 AMA −) and 100 matched controls were screened for IgG-Abs against Toxoplasma gondii, Helicobacter pylori, Epstein–Barr virus (EBV), cytomegalovirus (CMV), hepatitis B, and hepatitis C utilizing the BioPlex 2200 and ELISA kits (Bio-Rad Laboratories, USA).

Results

The prevalence of four anti-infectious agents Abs was significantly elevated among PBC patients when compared with controls, namely anti-T. gondii (ATxA; 71% vs. 40%, p < 0.0001), EBV early antigen (EA; 44% vs. 12%, p < 0.0001), H. pylori (54% vs. 31%, p < 0.01), and CMV (90% vs. 75%, p < 0.05) Abs, respectively. The co-occurrence of these four anti-infectious agents Abs was highly common in PBC, whereas this infection burden was rare in healthy subjects (20% vs. 3% respectively, p < 0.0001). Furthermore, specific infections interactions possibly increasing PBC risk were noted as well. Seropositivity of ATxA was inversely associated with cirrhosis among PBC patients (p < 0.05). Finally, no differences were observed between AMA − sera and their AMA + counterparts with regard to seroprevalence of any of the investigated infectious agents.

Conclusions

We note the association of ATxA and PBC, with the possibility of a milder disease manifestation. We also suggest that multiple exposures to infectious agents may contribute to PBC risk.     

Soluble apoptosis molecules in primary biliary cirrhosis: analysis and commitment of the Fas and tumour necrosis factor-related apoptosis-inducing ligand systems in comparison with chronic hepatitis C

Apoptosis in the liver is generated mainly by the Fas system. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has been proposed recently as a new apoptotic inducer. In the liver environment hepatocytes and biliary epithelial cells express TRAIL receptors which are up-regulated by increased levels of bile acids and during viral hepatitis. As for FasL, a soluble form of TRAIL has been described. To explore the commitment and level of activation of these two apoptotic systems in patients affected by primary biliary cirrhosis (PBC) or chronic hepatitis C (CH-C), a comparative study was drawn. Thirty patients with PBC on ursodeoxycholic acid have been enrolled. This group was compared with 30 patients with CH-C and with 20 healthy subjects. Soluble Fas ligand (sFasL) and soluble TRAIL (sTRAIL) levels were evaluated by double determinant immune assay and enzyme-linked immunosorbent assay (ELISA), respectively. Soluble FasL molecules were higher in PBC compared to CH-C (P=0 x 009). Soluble FasL was not detected in controls. Soluble TRAIL was significantly higher in CH-C patients compared to PBC (P=0 x 0001). Soluble TRAIL levels were higher in PBC and in CH-C than in controls (P=0 x 015 and P<0 x 001, respectively). No correlation between sFasL and sTRAIL, stage of disease, liver histology in each disease and cytolysis was present. Our data show different levels of commitment of TRAIL and Fas apoptosis-inducing systems in CH-C and PBC. Thus a different prominent role of TRAIL and Fas systems in the pathogenesis of these two conditions can be speculated: the former by inducing the death of infected hepatocytes, the latter by mediating the disappearance of bile duct.