An alternative therapy for graves' disease: clinical effects and mechanisms of an herbal remedy

Graves' disease, the most common cause of hyperthyroidism, is an autoimmune disorder. Antithyroid drugs have been selected as the first-line treatment of Graves' disease in Korea, Japan, and European countries. However, antithyroid drugs such as methimazole (MMI) and prophylthiouracil (PTU) have limitations in clinical applications because of their side effects. In this study, we performed a clinical trial and in vitro study to investigate the clinical effects and action mechanism of Ahnjeonbaekho-tang (AJBHT), an herbal remedy for Graves' disease. In a clinical study of Graves' disease patients who had side effects from antithyroid drugs, we found that treatment by AJBHT resulted in a reduction of serum triiodothyronine (T3) and free thyroxine (FT4) levels and an increase in thyroid stimulating hormone (TSH) levels (T3: p<0.0001, FT4: p=0.0012, TSH: p=0.0370, respectively). In vitro, AJBHT significantly inhibits FRTL-5 cell proliferation, DNA synthesis, cyclic AMP production, T4 synthesis, and the expression of thyroglobulin (Tg) mRNA in comparison with the control. These results suggest that AJBHT might suppress T(4) synthesis by modulating adenosine 3',5'-cyclic monophosphate (cAMP) and Tg expression, and therefore, AJBHT could be an alternative therapy for Graves' disease patients who have side effects from antithyroid drugs.     

Effect of cordycepin on interleukin-10 production of human peripheral blood mononuclear cells

Therapeutic options for controlling autoimmune diseases are still very limited. Interleukin-10 has been reported to be a promising approach to therapeutic intervention. In the search for a drug which results in the selective upregulation of interleukin-10, we investigated the immunoregulative effects of cordycepin. We have measured interleukin-10 and interleukin-2 secretion of human peripheral blood mononuclear cells that were incubated with cordycepin and assessed the influence of cordycepin on the expression of interleukin-10 mRNA, the proliferative response and the expression of surface markers on T lymphocytes. In addition, the subsets of interleukin-10-secreting cells, the influence of anti-interleukin-10 neutralizing antibody and cytotoxicity of cordycepin were evaluated. Our results suggest that cordycepin has a significantly upregulative effect on interleukin-10 production and interleukin-10 mRNA expression. Interleukin-10-producing cells included in CD4+, CD8+, CD19+, CD56+ and CD14+ cells. At the same time, cordycepin inhibited phytohaemagglutinin-induced interleukin-2 production and proliferation of peripheral blood mononuclear cells. A restricted T lymphocyte activation was also reflected by a reduced expression of the surface markers CD25, CD45RO, CD54, CD71 and HLA DR. Anti-interleukin-10 neutralizing antibody could not completely block the suppressive effect of cordycepin on production of interleukin-2. Cordycepin in the effective concentration presented slight cytotoxicity but did not increase apoptosis. These results indicate that cordycepin exerts immunoregulative effects. Further research on it may provide an approach for the development of novel immunomodulatory drugs which directly alter the secretion of cytokines.     

Anti-CD40 Treatment of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-exposed C57Bl/6 mice induces activation of antigen presenting cells yet fails to overcome TCDD-induced suppression of allograft immunity

We have previously demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suppressed the induction of the costimulatory molecule CD86 (B7-2) on B220+ and Mac-1+ spleen cells following the injection of allogeneic P815 tumor cells. In this study, TCDD exposure was shown to suppress CD54 and major histocompatibility complex (MHC) class II expression on B220+, Mac-1+, and CD11c+ splenic antigen presenting cells (APC). Furthermore, interleukin-12 (IL-12) production by spleen cells from P815-immunized mice was significantly decreased following exposure to TCDD. To determine if exogenous costimulation could enhance the activation of APC, vehicle- and TCDD-treated mice were injected with an agonistic antibody to murine CD40. Stimulation with anti-CD40 increased the expression of CD86, CD54, and MHC class II on splenic APC and greatly enhanced the production of interleukin-12. TCDD treatment had minimal effects on the anti-CD40-induced expression of accessory molecules on splenic APC. TCDD exposure had no effect on anti-CD40-induced IL-12 in the plasma but suppressed its production from cultured spleen cells. Surprisingly, although stimulation via CD40 increased the activation of APC, allograft effector functions were not restored in TCDD-treated mice, perhaps due to persistent defects in antigen processing and presentation, cytokine production, T cell function, or CD40-independent pathways of APC activation.     

Investigational drugs in early stage clinical trials for thyrotoxicosis with hyperthyroidism

ABSTRACT

Introduction: Thyrotoxicosis with hyperthyroidism is treated with these classical approaches (i) antithyroid drugs to blockade thyroid hormone release and normalize thyroid hormone production and (ii) destruction of the thyroid using radioiodine or surgical removal of the thyroid. The optimal medical therapy, especially for Graves´ disease, remains a subject of debate and there has been little progress in Graves’ disease therapeutics over the last decade.

Areas covered: Novel treatments of thyrotoxicosis with hyperthyroidism. This includes (i) small molecules such as synthetic thyroid hormone receptor antagonists and environmental molecules and (ii) molecules with interaction between thyroid stimulating hormone (TSH) receptor and TSH receptor antibodies such as M22, ANTAG3, org274179-0, 5C9, and K1-70. Other approaches to Graves´ disease treatment includes immunosuppressive treatment, glucocorticosteroids, rituximab, and intrathyroid injection of dexamethasone. Optimal iodine and selenium supplementation can also be considered.

Expert opinion: Clinical trials results suggest that novel thyroid treatments involving small molecule therapy, may predict a good future in Graves’ disease treatment; however, a greater understanding of these antagonists is needed. Other treatments comprising immunosuppressives have demonstrated a significant reduction of relapse of the disease, but are not recommended by international guidelines.     

硫脲类抗甲状腺药物的安全性问题

硫脲类抗甲状腺药物具有抑制甲状腺激素生成的作用,临床上用于治疗甲状腺功能亢进症。常见的硫脲类抗甲状腺药物有丙硫氧嘧啶和甲巯咪唑。其不良反应包括药疹、粒细胞缺乏症、严重肝损伤、抗中性粒细胞胞质抗体(ANCA)相关性血管炎等,并有一定的致畸作用。严重肝损伤和ANCA相关性血管炎的发生多与丙硫氧嘧啶有关,致畸作用主要见于甲巯咪唑。儿童和非妊娠期甲状腺功能亢进症患者的治疗首选甲巯咪唑,妊娠和哺乳期患者首选丙硫氧嘧啶。防治硫脲类抗甲状腺药物不良反应的措施包括:合理用药、定期监测、出现不良反应及时停药,以及对症治疗。     

In vivo administration of 15-deoxyspergulin inhibits antigen-presenting cell stimulation of T cells and NF-kappaB activation

15-Deoxyspergulin (DSG), a synthetic derivative of spergulin, was initially characterized for its antibiotic and antitumor effects. Recent studies have described the immunosuppressive properties of this molecule, but its mechanism of action is not clearly understood. In the study reported here, mice were treated in vivo with DSG prior to the measurement of IL-2 production and proliferation in an in vitro antigen presentation assay. At suboptimal antigen concentrations, elicited peritoneal macrophages or percoll isolated B cells from DSG-treated mice showed a 50-96% reduction in their ability to present chicken ovalbumin (cOva), cOva peptide, or superantigen (SAg) to MHC class II-matched antigen-specific primary T cells. No significant changes could be found in the cell surface expression of CD80, CD86, MHC I, MHC II, CD18, CD11b, CD40, CD25, and CD54 in antigen-presenting cells (APC) from control or DSG-treated animals. Activation with SAg of macrophages or splenocytes from DSG-treated mice revealed that there was a significant reduction in nuclear NF-kappaB levels compared to cells from untreated animals. Additionally, analysis of cytokines showed that production of TNF-alpha and IL-1beta was inhibited in cultures where macrophages from DSG-mice were used to present cOva to T cells. These results indicate that the effects of DSG in mice are not simply due to altered antigen processing or from any marked changes in cell surface antigen expression. Rather, the immunosuppression may arise from alterations in the release of one or more soluble factor from DSG-treated APC, which prevents effective antigen presentation and T cell activation.     

Plant alkaloid tetrandrine downregulates protein kinase C-dependent signaling pathway in T cells

Tetrandrine, a purified traditional Chinese medicinal herb that acts as an immunosuppressant and a Ca2+ channel blocker, has been clinically used to treat patients with arthritis, silicosis and hypertension. Since T cells play a critical role as autoreactive and pathogenic population in autoimmune diseases, in this study, we examined the immunosuppressive effect of tetrandrine on human peripheral blood T cells. We showed that tetrandrine inhibited phorbol 12-myristate 13-acetate (PMA) + ionomycin-induced T cell proliferation, interleukin-2 secretion and the expression of the T cell activation antigen, CD71. Further investigation of the molecular mechanism demonstrated that tetrandrine inhibited the expression of the protein kinase C-dependent interleukin-2 receptor alpha chain and CD69 but not the expression of the Ca2+-dependent CD40 ligand and CD69. Interestingly, when tetrandrine and cyclosporin A were added together, significant synergism in the suppression of T cell activation was observed. Moreover, of the several tetrandrine analogues studied, hernandezine was the most potent inhibitor of protein kinase C signaling events. These results also suggest that the protein kinase C-inhibitory capacity of tetrandrine and its analogues may not be associated with their function as Ca2+ channel blockers. Lastly, we showed that, within therapeutic concentrations, tetrandrine and its analogues could induce cellular apoptosis, which is defective in autoimmune diseases. In conclusion, our findings provide novel information about the molecular mechanism of the immunosuppressive effect of tetrandrine and its analogues in human peripheral blood T cells.     

Inhibition of DNA synthesis in peripheral blood mononuclear cells treated with phosphatidylserines containing unsaturated acyl chains.

The immunosuppressive action of phosphatidylserine has been studied in mitogen-activated human peripheral blood mononuclear cells. The addition of phospholipid (10-60 nmol/10(6) cells) causes a dose-dependent inhibition of DNA synthesis induced by PHA, anti-CD3 mAb, allogeneic lymphocytes and tetradecanoylphorbol acetate plus ionomycin. In contrast, the interleukin-2-dependent DNA synthesis is less affected. Flow cytometric analysis and binding of radioiodinated interleukin-2 show that the phospholipid prevents the expression of interleukin-2 and transferrin receptors. Removal of monocytes by adherence does not change the action of phosphatidylserine. Furthermore, the phospholipid is equally effective in preparations depleted of CD4+ or CD8+ lymphocytes. Phosphatidylinositol partly reproduces the action of phosphatidylserine. Phosphatidic acid, phosphatidylglycerol and phosphatidylcholine are inactive. Also unsaturated phosphatidylserine analogues inhibit DNA synthesis whereas saturated phosphatidylserines do not. The data suggest that phosphatidylserine mainly affect the steps of T cell activation preceding the production of interleukin-2 and the expression of its receptor. The phosphorylserine headgroup and the unsaturated acyl chains contribute to this effect.     

Antithyroid effects of propylthiouracil and sulfamonomethoxine in rats and monkeys

Experiments were performed to investigate the species difference in antithyroid effects of propylthiouracil (PTU) and sulfamonomethoxine (SMM). Sprague-Dawley rats were administered 30 mg/kg of PTU, or 30 or 270 mg/kg of SMM orally for 5 weeks, while squirrel monkeys received 30 mg/kg of PTU or 270 mg/kg of SMM. In rats receiving 30 mg/kg of PTU, a decrease of both serum 3,5,3'-triiodothyronine and thyroxine concentrations and of 131I incorporation into the thyroid hormone precursors was observed, together with elevation of serum thyroid-stimulating hormone concentration, an increase in thyroid weight, and hyperplasia of the follicular epithelium of the thyroid gland. Similar changes were seen in rats receiving 270 mg/kg of SMM; however, the antithyroid effects of SMM were less severe than those of PTU. No change was produced in monkey thyroids by 5-week treatments with 30 mg/kg of PTU or with 270 mg/kg of SMM. The molar concentration of PTU required for the in vitro inhibition of thyroid peroxidase was markedly lower in rats than in monkeys. SMM showed a similar species difference in the inhibition of thyroid peroxidase in vitro, but the enzyme inhibition of SMM was weaker than that of PTU. These findings suggest that rats were more sensitive to the antithyroid effects of PTU and SMM than monkeys, and that inhibition of thyroid peroxidase may play an important role in species difference in the antithyroid effects of the two drugs.     

Effects of mizoribine on MHC-restricted exogenous antigen presentation in dendritic cells

Mizoribine (MZR) has been shown to possess immunosuppressive activity that selectively inhibits the proliferation of lymphocytes by interfering with inosine monophosphate dehydrogenase. The efficacy of MZR is not only in patients who have had renal transplantation, but also in patients with rheumatoid arthritis (RA), lupus nephritis, and primary nephritic syndrome. Because the exact mechanism of its immunosuppressive action is not clear, the object of this study was to examine the ability of MZR to regulate the antigen presenting cells (APCs), dendritic cells (DCs). In this work, we tested whether MZR (1-10 microg/mL) could inhibit the cross-presentation of DCs. DC2.4 cells (H-2K(b)) or bone marrow-derived DCs (BM-DCs) generated from BM cells of C57BL/6 mouse (H-2K(b)) were cultured in the presence of MZR with OVA-microspheres, and the amount of OVA peptide-class I MHC complexes was measured by a T cell hybridoma, B3Z, that recognizes OVA (257-264 : SIINFEKL)-H-2Kb complex and expresses-galactosidase. MZR profoundly inhibited the expression of SIINFEKL-H-2K(b) complexes. This inhibitory activity of MZR appeared to affect the phagocytic activity of DCs. MZR also decreased IL-2 production when we examined the effects of MZR on CD4+ T cells. These results provide an understanding of the mechanism of immunosuppressive activity of MZR on the inhibition of MHC-restricted antigen presentation and phagocytic activity in relation to their actions on APCs.     

Extrathyroidal actions of antithyroid thionamides

Some compounds having thionamide structure inhibit thyroid functions. Such antithyroid thionamides include mercaptomethylimidazole (methimazole), thiourea and propylthiouracil, of which mercaptomethylimidazole is widely used to treat hyperthyroidism. Undesirable side effects develop from these drugs due to extrathyroidal actions. Antithyroid thionamides inhibit lactoperoxidase which contributes to the antibacterial activities of a number of mammalian exocrine gland secretions that protect a variety of mucosal surfaces. These drugs stimulate both gastric acid and pepsinogen secretions, thereby augmenting the severity of gastric ulcers and preventing wound healing. Increased gastric acid secretion is partially due to the H2 receptor activation, and also through the stimulation of the parietal cell by intracellular generation of H2O2 following inactivation of the gastric peroxidase-catalase system. Severe abnormalities may develop in blood cells and the immune system after thionamide therapy. It causes agranulocytosis, aplastic anemia, and purpura along with immune suppression. Olfactory and auditory systems are also affected by these drugs. Thionamide affects the sense of smell and taste and also causes loss of hearing. It binds to the Bowman's glands in the olfactory mucosa and causes extensive lesion in the olfactory mucosa. Thionamides also affect gene expression and modulate the functions of some cell types. A brief account of the chemistry and metabolism of antithyroid thionamides, along with their biological actions are presented.     

Boosting interleukin-10 production: therapeutic effects and mechanisms

More than forty cytokines have been extensively researched on the molecular structure, cell signaling and transduction pathway. With respect to cytokine-regulating therapy in immunological imbalance however, the reported results are conflicting because of the pleiotropic functions and the intricate interactions of the cytokine network. In this review, we outline the observations on interleukin-10 (IL-10) upregulatory therapy. Despite varying opinions on its therapeutic effects for different disorders, IL-10 has been considered a potential anti-inflammatory cytokine. Numerous studies support the view that IL-10 shows a strong suppressive effect on Th1 lymphocytes, antigen presenting cells and the production of inflammatory mediators. It is also noticeable that recent research has revealed the relationship between IL-10 induced antigen specific regulatory CD4+ T cells and antigen specific immune tolerance. This specific regulation was mediated in part through IL-10 secretion, because anti-IL-10 treatment reverted the inhibitory effect of regulatory T cell clones. In different models, these cells were shown to inhibit both Th1 and Th2-type inflammatory responses through the secretion of IL-10. With the presence of IL-10, regulatory T cells may induce peripheral immune tolerance. Exogenous administration, transgenic expression and endogenous stimulative agents of IL-10 have been used for a variety of inflammatory diseases, autoimmune diseases and allograft rejection in patients and experimental models. A therapeutic intervention with drug inducing endogenous IL-10 may be more practical than an exogenous administration of IL-10 with transient effect. Although further investigation on gene regulation of IL-10 is necessary, increasing studies have been reported concerning the attempt to develop the agents, which could promote endogenous IL-10 production for the treatment of immunological disorders and inflammatory diseases. With some unclear mechanisms, these agents have strongly upregulated IL-10 production in vitro or in vivo. Reported IL-10 upregulatory agents have shown promising prospects for remission of autoimmune diseases and inflammatory diseases and have even induced antigen specific immune tolerance. It is interesting that the IL-10 upregulatory effect of several traditional immunosuppressive drugs has been detected, e.g. glucocorticoid, which is considered "not more as an immunosuppressive drug but an immune modulating agent". Approximately twenty IL-10 upregulatory agents as instances are described in the present review. In addition, their therapeutic effects in various diseases are discussed.     

Anti-inflammatory action of Cudrania tricuspidata on spleen cell and T lymphocyte proliferation

This study examined whether an extract of Cudrania tricuspidata shows anti-proliferative effects in anti-CD3/CD28-mediated spleen and CD4+CD25- T cells and decreases the production of the proinflammatory cytokines interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in anti-CD3/CD28-mediated CD4+CD25- T cells. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4+CD25- T cells was effectively suppressed by C. tricuspidata. This extract, however, did not show cytotoxicity in spleen cells under conditions where the antigen was not stimulated using CCK-8 analysis. C. tricuspidata also decreased the production of the pro-inflammatory cytokines IL-2 and IFN-gamma by selective inhibition of this extract on proliferating cells in anti-CD3/CD28-mediated CD4+CD25- T cells. These results suggest that C. tricuspidata may be useful in the treatment of autoimmune diseases and organ transplantation through the inhibitory action of T cells in inflammation.     

Effect of topical immunomodulators on acute allergic inflammation and bronchial hyperresponsiveness in sensitised rats

We examined the effects of different immunomodulators administered topically on asthmatic responses in a rat model of asthma. Sensitised Brown-Norway rats were administered rapamycin, SAR943 (32-deoxorapamycin), IMM125 (a hydroxyethyl derivative of D-serine(8)-cyclosporine), and budesonide by intratracheal instillation 1 h prior to allergen challenge. Allergen exposure induced bronchial hyperresponsiveness, accumulation of inflammatory cells in bronchoalveolar lavage fluid, and also an increase in eosinophils and CD2+, CD4+ and CD8+ T cells in the airways. Interleukin-2, interleukin-4, interleukin-5, interleukin-10, and interferon-gamma mRNA expression was upregulated by allergen exposure. Budesonide abolished airway inflammation, suppressed the mRNA expression for interleukin-2, interleukin-4, and interleukin-5 (P<0.03), and bronchial hyperresponsiveness (P<0.05). IMM125 suppressed airway infiltration of eosinophils, and CD8+ T cells (P<0.02), and prevented the upregulated mRNA expression for interleukin-4, interleukin-5, and interferon-gamma (P<0.02). Rapamycin suppressed CD8+ T cell infiltration in airway submucosa (P<0.03), and mRNA expression for interleukin-2 (p<0.002), while SAR943 suppressed interleukin-2, interleukin-4, and interferon-gamma mRNA (P<0.05). IMM125, rapamycin and SAR943 did not alter airway submucosal CD2+ and CD4+ T cell infiltration, and bronchial hyperresponsiveness. CD8+ T cells, in contrast to CD4+ T cells, are more susceptible to the inhibition by IMM125 and rapamycin, which also caused greater suppression of Th1 compared to Th2 cytokine mRNA expression. In this acute model of allergic inflammation, differential modulation of Th1 and Th2 cytokines may determine the effects of various immunomodulators on airway inflammation and bronchial hyperresponsiveness.     

Effects of phenobarbital, pregnenolone-16alpha-carbonitrile, and propylthiouracil on thyroid follicular cell proliferation.

Reduced thyroid hormone concentrations (T4 and/or T3) and increased thyroid-stimulating hormone (TSH) have been proposed to mediate the thyroid tumor promoting effects of hepatic microsomal enzyme inducers (MEI) and antithyroid drugs. TSH is known to stimulate thyroid gland function and growth, as well as neoplasia. Thyroid weight has been used as an indicator of thyroid gland growth in MEI studies, but little is known about the effects of these inducers on thyroid cell proliferation. Therefore, we determined the time-course of thyroid cell proliferation of rats treated with MEI, and with the antithyroid drug propylthiouracil (PTU). Male Sprague-Dawley rats were fed either a basal diet or a diet containing phenobarbitol (PB) (1200 ppm), PCN (500 ppm), or PTU (30 ppm) for 3, 7, 14, 21, 30, 45, 60, or 90 days. PB and PCN treatments did not affect T3, but PTU reduced T3 60%. PB and PCN treatments reduced T4 25%, whereas PTU treatment reduced T4 90%. PB and PCN treatments increased thyroid weight 80%, and PTU increased thyroid weight 500%. TSH was not appreciably altered in PB-treated rats, but was increased 75% and 830% in PCN- and PTU-treated rats, respectively. Thyroid cell proliferation was increased 260, 330, and 850% in rats treated with PB, PCN, or PTU, respectively, for 7 days, but returned to control levels by the 45th treatment day. In conclusion, treatment with MEI that produced mild increases in TSH resulted in dramatic increases in thyroid cell proliferation, which peaked after 7 days of treatment and then returned to control values. This result is similar to that of antithyroid drugs, which produce large increases in TSH. These findings may have important implications for the role thyroid follicular cell proliferation has in mediating the thyroid tumor promoting effects of MEI.     

Molecular actions of calcineurin inhibitors

The immunosuppressive drugs cyclosporin A and FK-506, also called calcineurin inhibitors, have been useful for treating immune system-mediated diseases and have truly revolutionized allograft transplantation. Both drugs block T-cell proliferation by mechanisms that involve the inhibition of the key signaling phosphatase calcineurin, hence, the name calcineurin inhibitors. The inhibition of calcineurin activation by cyclosporin A and FK-506 blocks T-cell receptor-mediated production of interleukin-2 (IL-2), a growth factor critical for T-cell proliferation. Recent studies, however, suggest that the effects of the drugs are not limited to blocking calcineurin activation and IL-2 production. This review discusses the molecular actions of cyclosporin A and FK-506.     

Resveratrol induces the suppression of tumor-derived CD4+CD25+ regulatory T cells

CD4+CD25+ regulatory T cells (Treg cells) are negative regulator of the immune system and main obstacles to cancer immunotherapy in tumor-bearing hosts. Resveratrol is a natural product found in grapes with both immunomodulatory and anticancer effects, which can be controlled by Treg cells. Therefore, to determine whether resveratrol performs these actions via Treg cells, we investigated changes in Treg cell population and immunomodulatory cytokines in EG7 tumor-bearing C57BL/6 mice. In the present study, CD4+CD25+ cell population among CD4+ cells was inhibited ex vivo by resveratrol treatment in a dose-dependent manner. FoxP3+ expressing cells among CD4+CD25+ population were significantly reduced after resveratrol treatment ex vivo in intracellular FACS analysis. Single intraperitoneal administration of 4 mg/kg resveratrol suppressed the CD4+CD25+ cell population among CD4+ cells and downregulated secretion of TGF-beta, an immunosuppressive cytokine, measured from the spleens of tumor-bearing mice. Furthermore, resveratrol enhanced IFN-gamma expression in CD8+ T cells both ex vivo and in vivo,leading to immune stimulation. Taken together, these results suggest that resveratrol has a suppressive role on CD4+CD25+ cell population and makes peritumoral microenvironment unfavorable to tumor in tumor-bearing mice. Thus, resveratrol can be considered as possible adjuvant material for vaccination-based cancer therapy.     

Effects of glucocorticoids and cyclosporine on IL-2 and I kappa B alpha mRNA expression in human peripheral blood mononuclear cells

To evaluate molecular mechanisms that might account for the heterogeneity in the in vitro responsiveness of individual subjects' peripheral blood mononuclear cells (PBMC) to immunosuppressive drugs, the authors quantitated in normal human cells the suppressive effects of the glucocorticoids prednisolone and methylprednisolone and of cyclosporine on interleukin-2 (IL-2) mRNA expression and IL-2 production, as well as the stimulatory effect of these drugs on IkappaBalpha mRNA expression. As expected, cyclosporine was significantly more suppressive than either glucocorticoid of IL-2 mRNA expression and IL-2 production by mitogen-stimulated PBMC, with variable degrees of inhibition in cells from individual subjects. The authors confirmed in human PBMC the stimulation of IkappaBalphamRNA expression by the glucocorticoid reported by others in HeLa and transfected Jurkat cell lines. In addition, the authors observed a stimulatory effect on IkappaBalpha mRNA expression by cyclosporine as well in 8 of 10 PBMC preparations studied, suggesting a possible role of calcineurin in the regulation of IkappaBalpha production. Interindividual variability in the intracellular mechanisms of action, possibly based on molecular polymorphisms, might be one factor contributing to differences among patients in their clinical responses to treatment with such drugs.     

Prevention of graft-versus-host disease by a novel immunosuppressant, (5R)-5-hydroxytriptolide (LLDT-8), through expansion of regulatory T cells

(5R)-5-hydroxytriptolide (LLDT-8) is a new compound derived from triptolide, which is the major immunosuppressive fraction of Tripterygium wilfordii Hook. F (TWHF). In this study, we demonstrated that administration of LLDT-8 (1 mg/kg/day, p.o.) effectively prevented weight loss and death induced by allo-BMT (BLAB/c, H-2d to C57BL/6, H-2b), and extended survival in allo-BMT model of aGVHD. Following days 7 to 28 after allo-BMT, the allogeneic graft survived by increasing the number of engrafted cells (H-2d) in spleens of recipient mice with LLDT-8 treatment. To construe the immunosuppressive effects of LLDT-8, the splenocytes (H-2d) of LLDT-8 treated recipients (H-2b) were tested for the proliferative responses to donor antigen (H-2d), host antigen (H-2b) and mitogen (ConA) stimulations, respectively, the results indicated that LLDT-8 induced the T cells' unresponsiveness to donor and host antigens, while still maintaining response to ConA; Compared with the vehicle group of GVHD mice, administration of LLDT-8 significantly inhibited T cells to produce IFN-gamma with or without host antigen or ConA stimulation. Further studies indicated LLDT-8 had a normalizing effect on the ratio of CD4+/CD8+ T cells, and increased CD4+CD25+ T regulatory cells with the Foxp3 expression in splenocytes from LLDT-8 treated mice. The results outline the great potential of LLDT-8 as a therapeutic tool to induce suppression in GVHD.     

Modifications of the immune responsiveness in patients with autoimmune thyroiditis: evidence for a systemic immune alteration

Hashimoto's thyroiditis, the most common form of autoimmune thyroid disease, is characterised by lymphocytic infiltration of the thyroid gland, gradual destruction of the organ and production of thyroid specific auto antibodies (antithyroid peroxidase and antithyroglobulin antibodies). There are evidences that cast doubt on the pathogenetic role of these antibodies in thyroid autoimmunity. It is very likely that cellular destruction is mediated by other cellular mechanisms, such as auto reactive T-lymphocytes, natural killer and cytokines. However, other studies performed in animal models have led to the conclusion that organ specific autoimmune thyroiditis should be regarded as a polygenic disease with a penetrance that is strongly influenced by environmental factors. According to our recent results, patients affected by autoimmune thyroiditis exhibited a decreased percentage of NK and CD25 + bearing cells significantly in comparison to normal controls. Altogether these data indicated that in the patients with autoimmune thyroid disease a certain degree of peripheral immune deficiency was present.