Bone marrow transplantation, refractory autoimmunity and the contributions of Susumu Ikehara

Hematopoietic stem cell transplantation for systemic lupus erythematosus

Two streams of research are at the origin of the utilization of hematopoietic stem cell transplantation (HSCT) for severe autoimmune diseases (SADs). The allogeneic approach came from experimental studies on lupus mice, besides clinical results in coincidental diseases. The autologous procedure was encouraged by researches on experimental neurological and rheumatic disorders. At present the number of allogeneic HSCT performed for human SADs can be estimated to not over 100 patients, and the results are not greatly encouraging, considering the significant transplant-related mortality (TRM) and the occasional development of a new autoimmune disorder and/or relapses notwithstanding full donor chimerism. Autologous HSCT for refractory SLE has become a major target. Severe cases have been salvaged, TRM is low and diminishing, and prolonged clinical remissions are obtainable. Two types of immune resetting have been established, "re-education" and regulatory T cell (Tregs) normalization. Allogeneic HSCT for SLE seems best indicated for patients with disease complicated by an oncohematologic malignancy. Autologous HSCT is a powerful salvage therapy for otherwise intractable SLE. The duration of remission in uncertain, but a favorable response to previously inactive treatments is a generally constant feature. The comparison with new biological agents, or the combination of both, are to be ascertained.

Successful modulation of type 2 diabetes in db/db mice with intra-bone marrow--bone marrow transplantation plus concurrent thymic transplantation

There is increasing evidence that both autoimmune and autoinflammatory mechanisms are involved in the development of not only type 1 diabetes mellitus (T1 DM), but also type 2 diabetes mellitus (T2 DM). Our laboratory has focused on this concept, and in earlier efforts replaced the bone marrow cells (BMCs) of leptin receptor-deficient (db/db) mice, an animal model of T2DM, with those of normal C57BL/6 (B6) mice by IBM-BMT. However, the outcome was poor due to incomplete recovery of T cell function. Therefore, we hypothesized that intra-bone marrow-bone marrow transplantation plus thymus transplantation (IBM-BMT + TT) could be used to treat T2 DM by normalizing the T cell imbalance. Hence we addressed this issue by using such dual transplantation and demonstrate herein that seven weeks later, recipient db/db mice manifested improved body weight, reduced levels of blood glucose, and a reduction of plasma IL-6 and IL-1β. More importantly, this treatment regimen showed normal CD4/CD8 ratios, and increased plasma adiponectin levels, insulin sensitivity, and the number of insulin-producing cells. Furthermore, the expression of pancreatic pAKT, pLKB1, pAMPK and HO-1 was increased in the mice treated with IBM-BMT + TT. Our data show that IBM-BMT + TT treatment normalizes T cell subsets, cytokine imbalance and insulin sensitivity in the db/db mouse, suggesting that IBM-BMT + TT is a viable therapeutic option in the treatment of T2 DM.

Salivary epithelial cells from Sjogren's syndrome patients are highly sensitive to anoikis induced by TLR-3 ligation

In certain types of cells, Toll-like receptor-3 (TLR-3) ligation by viral dsRNA induces apoptotic death, likely engaged into the elimination of virus-infected cells. We have previously shown that TLR-3 ligation on cultured non-neoplastic salivary gland epithelial cells (SGEC) with polyI:C (a synthetic analogue of viral dsRNA) results in the induction of surface immunoactive molecules, however, the pro-apoptotic effect of such signaling has not been addressed. In this study, polyI:C-treated SGEC were found to suffer severe detachment from substratum and subsequent apoptosis, a phenomenon suggestive of anoikis or anoikia (detachment-induced apoptosis). PolyI:C-induced anoikis in SGEC was associated with the upregulation of the pro-apoptotic Bmf, BimEL and Bax and the down-regulation of the pro-survival Bcl-2 (real-time PCR analyses). Finally, the comparative analysis of SGEC lines derived from primary Sjogren's syndrome (SS) patients (SS-SGEC) and non-SS controls had revealed that SS-SGEC are particularly susceptible to TLR-3-induced anoikis, as it was triggered by suboptimally low concentrations of polyI:C. This finding correlated with significantly higher constitutive surface TLR-3 expression by SS-SGEC, a feature indicative of their intrinsic activation status. In conclusion, TLR-3 signaling pathway in the salivary epithelium appears to extend beyond the induction of innate immune responses and to involve the activation of programmed-cell death via anoikis. In the same context, the increased vulnerability of SS-SGEC to the injurious effect of TLR-3 ligation is likely associated with the intrinsic activation processes that apparently operate in the epithelia of SS patients, and a feature of key pathogenetic importance for the disorder.

In vivo modulation of angiogenesis by beta 2 glycoprotein I

Beta 2 glycoprotein I (β2GPI) is the major auto antigen in the antiphospholipid syndrome but also interacts with fibrinolytic and angiogenic proteins. The aim of this study was to examine the angiogenic potential of β2GPI in vivo in β2GPI deficient mice utilizing angiogenic assays. β2GPI deficient mice show increased microvessel formation in comparison to β2GPI replete controls when injected with growth factor free-matrigel implants. However, microvessel formation in matrigel plugs of β2GPI deficient mice was less than in β2GPI replete mice when basic fibroblast growth factor (bFGF) was included in the matrigel. Hemoglobin content was higher in vascular endothelial growth factor (VEGF) containing-matrigel plugs in the β2GPI deficient mouse demonstrating that the lack of β2GPI led to increased extravasation by VEGF. Melanoma B16F10 tumour growth was enhanced in β2GPI deficient mice. Melanoma microvessel density was increased in β2GPI deficient mice but the proliferation rate of tumour cells (determined by Ki67 immunohistochemistry) was unaffected by the presence or absence of β2GPI. Subcutaneous delivery of native human β2GPI by the ALZET osmotic pump did not affect melanoma tumour growth in β2GPI deficient mice. We conclude that the in vivo unopposed action of β2GPI is anti-angiogenic however this function is modified in the presence of a strong angiogenic stimulus into stabilization of vessel formation. Although the presence of β2GPI attenuates vessel sprouting in certain tumours, no survival benefit is conferred to tumour bearing animals. This does not preclude the potential benefit of modified or fragments of β2GPI in anti-angiogenesis research.

The use of mouse models to better understand mechanisms of autoimmunity and tolerance

A major emphasis of our studies has been on developing a better understanding of how and why the skin serves as a target for immune reactions as well as how the skin evades becoming a target for destruction. For these studies we developed transgenic mice that express a membrane-tethered form of a model self antigen, chicken ovalbumin (mOVA), under the control of a keratin 14 (K14) promoter. K14-mOVA transgenic mice that express OVA mRNA and protein in the epithelia have been assessed for their immune responsiveness to OVA and are being used as targets for T cells obtained from OT-1 transgenic mice whose CD8+ T cells carry a Vα2/Vβ5-transgenic T cell receptor with specificity for the OVA(257-264)-peptides (OVAp) in association with class I MHC antigens. Some of the K14-mOVA transgenic mice develop a graft-versus-host-like disease (GvHD) when the OT-1 cells are injected while others appear to be tolerant to the OT-1 cells. We found that γc cytokines, especially IL-15, determine whether autoimmunity or tolerance ensues in K14-mOVA Tg mice. We also developed transgenic mice that express soluble OVA under the control of a K14 promoter (K14-sOVA) that die within 5-8 days after adoptive transfer of OT-1 cells and identified these mice as a model for more acute GvHD-like reactions. Spontaneous autoimmunity occurs when these K14-sOVA mice are crossed with the OT-I mice. In contrast, we found that preventive or therapeutic OVAp injections induced a dose-dependent increase in survival. In this review the characterization of 5 strains of K14-OVATg mice and underlying mechanisms involved in autoimmune reactions in these Tg mice are discussed. We also describe a strategy to break tolerance and describe how the autoimmunity can be obviated using OVAp. Finally, a historical overview of using transgenic mice to assess the mechanisms of tolerance is also provided.

The spectrum of autoantibodies in IPEX syndrome is broad and includes anti-mitochondrial autoantibodies

IPEX syndrome is a congenital disorder of immune regulation caused by mutations in the FOXP3 gene, which is required for the suppressive function of naturally arising CD4 + CD25 + regulatory T cells. In this case series we evaluated serum samples from 12 patients with IPEX syndrome for the presence of common autoantibodies associated with a broad range of autoimmune disorders. We note that 75% of patients (9/12) had 1 or more autoantibodies, an incidence far above the cumulative rate observed in the general population. The range of autoantibodies differed between patients and there was no predominant autoantibody or pattern of autoantibodies present in this cohort. Surprisingly, one patient had high-titer anti-mitochondrial antibodies (AMA) typically associated with primary biliary cirrhosis (PBC) although the patient had no signs of cholestasis. PBC is a well-characterized autoimmune disease that occurs primarily in women and includes the serological hallmarks of serum AMA and elevated IgM which were both present in this patient. PBC is virtually absent in children with the exception of one reported child with interleukin 2 receptor α (CD25) deficiency which is associated with an IPEX-like regulatory T cell dysfunction. Based on the present data and the available literature we suggest a direct role for CD4 + CD25 + regulatory T cells in restraining B cell autoantibody production and that defects in regulatory T cells may be crucial to the development of PBC.

Update on the genetics and genomics of PBC

Despite recent progress, the pathogenic mechanisms governing PBC development, treatment response and outcome remain unknown. This deficiency is in large part due to the complex nature of PBC, wherein various environmental factors may be capable of prompting disease, but only in the context of underlying genetic susceptibility. Identification of genomic loci containing these heritable risk factors has been slowed by the rarity and late onset of PBC, which has made difficult the collection of sufficient numbers of patients and family members for meaningful genetic analyses. Advancements in our ability to catalog the genetic variation in large numbers of individuals at a genome-wide scale, coupled with unprecedented efforts to recruit PBC patients for genetic study, positions us to generate data that could fundamentally change our understanding of PBC and lead to clinical innovation. Indeed, the first genome-wide association study for PBC has been published, in which multiple genes involved with IL12 signaling, a pathway that is being targeted in treatment of other inflammatory conditions, were implicated in disease. However, this study was relatively small in the genome-wide milieu and a significantly expanded effort will be necessary to truly elucidate the genetic architecture of PBC. Moving ahead, cooperation between the groups collecting biospecimens and generating genome-wide data from large numbers of patients with PBC will be essential, not only to increase power for fine mapping and future studies of rare variants and epistasis; but to streamline efforts to perform functional validation of novel discoveries. Here we provide a brief update of the current state of genetics in PBC to form a basis for understanding the considerable progress that is likely to be made in the coming years.

Phenotypical and functional alterations of CD8 regulatory T cells in primary biliary cirrhosis

The mechanisms that lead to loss of tolerance in autoimmune disease have remained both elusive and diverse, including both genetic predisposition and generic dysregulation of critical mononuclear cell subsets. In primary biliary cirrhosis (PBC), patients exhibit a multilineage response to the E2 component of pyruvate dehydrogenase involving antibody as well as autoreactive CD4 and CD8 responses. Recent data from murine models of PBC have suggested that a critical mechanism of biliary destruction is mediated by liver-infiltrating CD8 cells. Further, the number of autoreactive liver-infiltrating CD4 and CD8 cells is significantly higher in liver than blood in patients with PBC. Based on this data, we have studied the frequencies and phenotypic characterization of both CD4 and CD8 regulatory T cell components in both patients with PBC and age-sex matched controls. Our data is striking and indicate that CD8 Treg populations from PBC patients, but not controls, have significant phenotypic alterations, including increased expression of CD127 and reduced CD39. Furthermore, in vitro induction of CD8 Tregs by incubation with IL10 is significantly reduced in PBC patients. Importantly, the frequencies of circulating CD4+CD25+ and CD8+ and CD28- T cell subpopulations are not significantly different between patients and controls. In conclusion, these data identify the CD8 Treg subset as a regulatory T cell subpopulation altered in patients with PBC.

Pathogenetic aspects of systemic lupus erythematosus with an emphasis on regulatory T cells

The development of autoimmune diseases is characterized by the breakdown of mechanism(s) that are responsible for maintaining immunological tolerance against self-structures in the periphery. Several aberrations of immune cells have been described so far. Most recently quantitative and/or qualitative defects of T cells with the capacity to suppress or regulate the proliferation of effector T cells in vitro - subsequently termed regulatory T cells (Treg) - have been suggested to substantially contribute to the imbalance of peripheral tolerance and trigger the outbreak of autoimmune reactions. The aim of this article is to summarize current knowledge about pathomechanisms that are involved in the development of autoimmunity with a special emphasis on the role of Treg in patients with systemic lupus erythematosus (SLE).

A novel mechanism of thrombosis in antiphospholipid antibody syndrome

Antiphospholipid antibody syndrome (APS) is an autoimmune thrombophilia mediated by autoantibodies directed against phospholipid-binding plasma proteins, mainly β2 Glycoprotein I (β2GPI)-a plasma apolipoprotein and prothrombin (PT). A subgroup of these antibodies termed "Lupus Anticoagulant" (LA) elongate in vitro the clotting times, this elongation not corrected by adding normal plasma in the detection system. The exact mechanism by which these autoantibodies induce thrombosis is not well understood. Resistance to natural anticoagulants such as protein C, impaired fibrinolysis, activation of endothelial cells to a pro-coagulant phenotype and activation of platelets, are among the mechanisms partially supported by experimental evidence. Artificially dimerized β2GPI binds tightly to platelet membrane activating them. We search for mechanisms of natural dimerization of β2GPI by proteins of the platelet membranes and found that platelet factor 4 (PF4) assembled in homotetramers binds two molecules of β2GPI and this complex is recognized by anti-β2GPI antibodies, the whole complexes being thrombogenic in terms of activating platelets as confirmed by p38MAP kinase phosphorylation and thromboxane B2 production. Of note PF4/heparin complexes are also immunogenic triggering the production of anti-PF4/heparin antibodies which activate also platelets (the so-called "heparin-induced thrombocytopenia and thrombosis syndrome", HITT). The anti-β2GPI antibodies activate platelets by their F(ab)2, while the anti-PF4/heparin by their Fc fragments. Thus PF4 is a common denominator in the pathogenesis of APS and HITT which share also clinical characteristics such as thrombocytopenia and thrombosis.

Sjögren syndrome: advances in the pathogenesis from animal models

Sjögren syndrome is an autoimmune disease characterized by hyposecretion of the lacrimal and salivary glands, resulting in dryness of the eyes and mouth. Individuals may experience primary Sjögren syndrome or a secondary form accompanying another rheumatic autoimmune disease, such as rheumatoid arthritis or systemic lupus erythematosus. The pathogenic mechanisms of Sjögren syndrome remain largely unknown, in part a consequence of the heterogeneity of the disease. Animal models have shed light on the connections between specific pathways and symptoms, but an ideal system is wanting. Improved disease models will enable a better understanding of Sjögren syndrome, including how immune tolerance is lost and potential therapeutic interventions. Most importantly, an optimal model will enable detection of disease biomarkers, since injury to the salivary glands may precede lymphocytic infiltration. This review aims to characterize available mice models of Sjögren syndrome, including advantages and disadvantages, from the researcher's perspective.

Alternatively activated macrophages in infection and autoimmunity

Macrophages are innate immune cells that play an important role in activation of the immune response and wound healing. Pathogens that require T helper-type 2 (Th2) responses for effective clearance, such as parasitic worms, are strong inducers of alternatively activated or M2 macrophages. However, infections such as bacteria and viruses that require Th1-type responses may induce M2 as a strategy to evade the immune system. M2 are particularly efficient at scavenging self tissues following injury through receptors like the mannose receptor and scavenger receptor-A. Thus, M2 may increase autoimmune disease by presenting self tissue to T cells. M2 may also exacerbate immune complex (IC)-mediated pathology and fibrosis, a hallmark of autoimmune disease in women, due to the release of profibrotic factors such as interleukin-1beta, transforming growth factor-beta, fibronectin and matrix metalloproteinases. We have found that M2 comprise anywhere from 30% to 70% of the infiltrate during acute viral or experimental autoimmune myocarditis, and shifts in M2 populations correlate with increased IC deposition, fibrosis and chronic autoimmune pathology. Thus, women may be at an increased risk of M2-mediated autoimmunity due to estrogen's ability to increase Th2 responses.

Serum inflammatory cytokines, complement components, and soluble interleukin 2 receptor in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic cholestatic autoimmune liver disease characterized by selective destruction of the intrahepatic bile ducts and highly specific serum anti-mitochondrial autoantibodies (AMA). Several studies have attempted to determine the cytokine pattern characterizing PBC, yet no definitive data have been gathered. The present study was designed to evaluate pro-inflammatory cytokines (IL-1beta, IL-6, TNFalpha), soluble IL-2 receptor (sIL-2R, e.g. soluble CD25), and complement components (C1q, C3, factor B, properdin) levels in sera from 84 patients with PBC and 41 controls. PBC was characterized by significantly higher levels of all pro-inflammatory cytokines when compared to controls; these included IL-1beta (433.3 +/- 13.2 vs. 316.6 +/- 14.7 pg/ml, P < 0.001), IL-6 (701 +/- 17.4 vs. 158 +/- 22.5 pg/ml, P < 0.001), TNFalpha (3.38 +/- 0.6 pg/ml vs. undetectable, P = 0.001), and sIL-2R (1527.1 +/- 106 vs. 566.4 +/- 28.7 U/ml, P < 0.001). Similarly, all complement components were also significantly higher in PBC compared to control sera. In conclusion, PBC sera manifest higher levels of sIL-2R and complement components and this may reflect a perpetuated immune activation. As expected, we also report that all major pro-inflammatory cytokine levels are enhanced in PBC. Further longitudinal analyses could demonstrate a correlation between these markers and disease stage or inflammatory activity, to predict histological staging, disease activity, and response to treatment.

Autoimmunity in retinal degeneration: autoimmune retinopathy and age-related macular degeneration

Autoantibody production is associated with a variety of ocular disorders, including autoimmune retinopathy (AIR) and age-related macular degeneration (AMD). A breakdown of immunologic tolerance (ocular immune privilege), including the blood-retinal barrier, anti-immune and anti-inflammatory proteins, and anterior chamber-associated immune deviation may play important roles in these disorders. Although the exact triggers for ocular autoimmunity are unknown, autoimmune targeting of retinal tissue is clearly associated with and may contribute to the pathogenesis of both AIR and AMD. Autoantibody production has long been associated with AIR, a collection of disorders that includes cancer-associated retinopathy, melanoma-associated retinopathy and non-paraneoplastic autoimmune retinopathy. A growing body of evidence indicates that AMD pathogenesis, too, involves ocular inflammation and autoimmunity. Identification and quantification of autoantibodies produced in patients with AIR and AMD may assist with diagnosis, prognosis, and choice of treatments. Animal models that allow investigation of ocular autoimmunity will also be needed to better understand the disease processes and to develop novel therapies. In this review we discuss ocular immune privilege and potential mechanisms of autoimmunity in the eye. We describe how autoimmunity relates to the pathogenesis of AIR and AMD. We explain how the antigen microarray technique is used to detect autoantibodies in patient serum samples, and discuss how current animal models for AMD can be used to investigate autoimmune pathogenesis. Finally, we outline unanswered questions and exciting areas of future study related to autoimmune retinal degeneration.

Emerging roles of TLR7 and TLR9 in murine SLE

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by B cell hyperactivity leading to the production of various autoantibodies and subsequent development of glomerulonephritis, i.e. lupus nephritis. Among the principal targets of autoantibodies produced in murine SLE are nucleic acid-protein complexes, such as chromatin and ribonucleoproteins, and the envelope glycoprotein gp70 of endogenous retroviruses. The preferential production of these autoantibodies is apparently promoted by the presence of genetic abnormalities leading to defects in the elimination of apoptotic cells and to an enhanced expression of endogenous retroviruses. Moreover, recent studies revealed that the innate receptors TLR7 and TLR9 are critically involved in the activation of dendritic cells and autoreactive B cells through the recognition of endogenous DNA- or RNA-containing antigens and subsequent development of autoimmune responses against nuclear autoantigens. Furthermore, the regulation of autoimmune responses against endogenous retroviral gp70 by TLR7 suggested the implication of endogenous retroviruses in this autoimmune response. Clearly, further elucidation of the precise molecular role of TLR7 and TLR9 in the development of autoimmune responses will help to develop novel therapeutic strategies and targets for SLE.

Autoimmune thyroiditis: a model uniquely suited to probe regulatory T cell function

Murine experimental autoimmune thyroiditis (EAT) is a model for Hashimoto's thyroiditis that has served as a prototype of T cell-mediated autoimmunity for more than three decades. Key roles for MHC restriction and autoantigen influence on susceptibility to autoimmunity have been demonstrated in EAT. Moreover, it has served a unique role in investigations of self tolerance. In the early 1980s, self tolerance and resistance to EAT induction could be enhanced by increasing circulating levels of the autoantigen, thyroglobulin (Tg), by exogenous addition as well as endogenous release. This observation, directly linking circulating self antigen to self tolerance, led to subsequent investigations of the role of regulatory T cells (Tregs) in self tolerance. These studies revealed that protection against autoimmunity, in both naive and tolerized mice, was mediated by thymically-derived CD4(+)CD25(+)Foxp3(+) Tregs. Moreover, these naturally-existing Tregs required proper costimulation, in context with autoantigen presentation, to maintain and enhance self tolerance. In particular was the selected use of MHC- and heterologous Tg-restricted models from both conventional and transgenic mice. These models helped to elucidate the complex interplay between autoantigen presentation and MHC class II-mediated T cell selection in the development of Treg and autoreactive T cell repertoires determining susceptibility to autoimmunity. Here we describe these investigations in further detail, providing a context for how EAT has helped shape our understanding of self tolerance and autoimmunity.

Recent insights in the epidemiology of autoimmune diseases: improved prevalence estimates and understanding of clustering of diseases

Previous studies have estimated a prevalence of a broad grouping of autoimmune diseases of 3.2%, based on literature review of studies published between 1965 and 1995, and 5.3%, based on national hospitalization registry data in Denmark. We examine more recent studies pertaining to the prevalence of 29 autoimmune diseases, and use these data to correct for the underascertainment of some diseases in the hospitalization registry data. This analysis results in an estimated prevalence of 7.6-9.4%, depending on the size of the correction factor used. The rates for most diseases for which data are available from many geographic regions span overlapping ranges. We also review studies of the co-occurrence of diseases within individuals and within families, focusing on specific pairs of diseases to better distinguish patterns that may result in insights pertaining to shared etiological pathways. Overall, data support a tendency for autoimmune diseases to co-occur at greater than expected rates within proband patients and their families, but this does not appear to be a uniform phenomenon across all diseases. Multiple sclerosis and rheumatoid arthritis is one disease pair that appears to have a decreased chance of coexistence.

Environmental triggers of autoimmune thyroiditis

Autoimmune thyroiditis is among the most prevalent of all the autoimmunities. Autoimmune thyroiditis is multifactorial with contributions from genetic and environmental factors. Much information has been published about the genetic predisposition to autoimmune thyroiditis both in experimental animals and humans. There is, in contrast, very little data on environmental agents that can serve as the trigger for autoimmunity in a genetically predisposed host. The best-established environmental factor is excess dietary iodine. Increased iodine consumption is strongly implicated as a trigger for thyroiditis, but only in genetically susceptible individuals. However, excess iodine is not the only environmental agent implicated as a trigger leading to autoimmune thyroiditis. There are a wide variety of other synthetic chemicals that affect the thyroid gland or have the ability to promote immune dysfunction in the host. These chemicals are released into the environment by design, such as in pesticides, or as a by-product of industry. Candidate pollutants include polyaromatic hydrocarbons, polybrominated biphenols, and polychlorinated biphenols, among others. Infections are also reputed to trigger autoimmunity and may act alone or in concert with environmental chemicals. We have utilized a unique animal model, the NOD.H2(h4) mouse to explore the influence of iodine and other environmental factors on autoimmune thyroiditis.

Spontaneous autoimmune myocarditis and cardiomyopathy in HLA-DQ8.NODAbo transgenic mice

Most individuals have viral infections at some point in their life, however, only few develop autoreactivity to cardiac myosin following infection suggesting a genetic predisposition. Population studies have shown that among all the genetic factors linked with autoimmune disease development, MHC class II genes are the most significant genetic factors. Experimental autoimmune myocarditis resembling human Dilated cardiomyopathy can be induced in susceptible mice by infection with coxsackie virus as well as immunization with purified foreign and murine cardiac specific a-myosin. We generated transgenic mice lacking endogenous class II molecules, HLA-DR3.Abo and HLA-DQ8.Abo transgenic mice in NOD and HLA-DQ8.Abo in B10 background, to study the role of MHC in spontaneous autoimmunity. The HLA molecules in these mice are expressed on cell surface and can positively select CD4+ T cells expressing various Vb T cell receptors. NOD.DQ8 female mice spontaneously developed myocarditis and dilated cardiomyopathy. Histopathology of heart revealed mononuclear infiltrate consisting of CD4 and Mac-1+ cells and myocyte necrosis. NOD.DQ8 mice showed cellular and humoral autoreactive response to self cardiac myosin.. Depletion of CD8 and CD4 + cells suggested that CD8 T cells may act as regulatory cells while CD4 cells are required as effector cells. NOD.DR3 and B10.DQ8 mice did not develop any cardiac pathology suggesting DQ8 is required for predisposition to the spontaneous autoreactivity while NOD background influences onset and progression of disease. Thus these mice provide powerful tools to understand the role of HLA class II molecules in predisposition and onset of human diseases and to develop immunotherapy.

Self heat-shock protein 65-mediated regulation of autoimmune arthritis

Heat-shock proteins (Hsps) have been invoked in the pathogenesis of a variety of autoimmune diseases. The mycobacterial heat-shock protein 65 (Bhsp65) has been studied extensively as one of the antigenic triggers of autoimmunity in experimental models of, as well as patients with, rheumatoid arthritis. As Hsps are highly conserved and immunogenic, it is generally anticipated that self Hsps might serve as the endogenous targets of the immune response initiated by the homologous foreign Hsps. Contrary to this expectation, studies in the rat adjuvant arthritis (AA) model have revealed that priming of the self (rat) hsp65 (Rhsp65)-directed T cells in the Lewis rat leads to protection against AA instead of disease induction or aggravation. The arthritis-protective attribute of the self hsp65 is also evident following spontaneous priming of the anti-Rhsp65 T cells during the natural course of AA. Furthermore, immunization of rats with human hsp60, or with Bhsp65 peptides that are crossreactive with the corresponding self hsp65 peptides, leads to protection against AA. Importantly, high levels of T cell reactivity against self hsp60 in patients with juvenile idiopathic arthritis positively correlate with a favorable outcome of the disease. Thus, immune response against self hsp65 in autoimmune arthritis is protective rather than being pathogenic.

Matrix metalloproteinase and G protein coupled receptors: co-conspirators in the pathogenesis of autoimmune disease and cancer

Similarities in the pathologies of autoimmune diseases and cancer have been noted for at least 30 years. Inflammatory cytokines and growth factors mediate cell proliferation, and proteinases, especially the collagenase, Matrix Metalloproteinase-1 (MMP-1), contribute to disease progression by remodeling the extracellular matrix and modulating the microenvironment. This review focuses on two cancers (melanoma and breast) and on the autoimmune disorder, rheumatoid arthritis (RA), and discusses the activated stromal cells found in these diseases. MMP-1 was originally thought to function only to degrade interstitial collagens, but recent studies have revealed novel roles for MMP-1 involving the G protein-coupled receptors: the chemokine receptor, CXCR-4, and Protease Activated Receptor-1 (PAR-1). Cooperativity between MMP-1 and CXCR4/SDF-1 signaling influences the behavior of activated fibroblasts in both RA and cancer. Further, MMP-1 is a vital part of an autocrine/paracrine MMP-1/PAR-1 signal transduction axis, a function that amplifies its potential to remodel the matrix and to modify cell behavior. Finally, new therapeutic agents directed at MMP-1 and G protein-coupled receptors are emerging. Even though these agents are more specific in their targets than past therapies, these targets are often shared between RA and cancer, underscoring fundamental similarities between autoimmune disorders and some cancers.

Navigating the passage between Charybdis and Scylla: recognizing the achievements of Noel Rose

This special edition of the Journal of Autoimmunity is dedicated to celebrate the enormous contributions of Dr. Noel Rose, a physician-scientist, someone that can be readily anointed as a gifted scientist who laid down the foundation and fundamental concepts of human autoimmunity. Dr. Rose performed a series of landmark studies that extend back more than 50 years and whose work is the cornerstone of the commonly used term "from the bench to the bedside." The studies included not only characterization of a normal immune response but, more importantly, defining the nature of not only the antigen, but also the aberrant response that results in organ, tissue specific reactions and immunopathology. These pioneering studies contributed to the biochemical nature of antigens, dissection of the immune repertoire, the recognition of the importance of genetics and environment, and the distinctions between a normal and an autoimmune response. Hence, this volume has been coined "Navigating the Passage Between Charybdis and Scylla: Recognizing the Achievements of Noel Rose."

Application of tissue-specific NK and NKT cell activity for tumor immunotherapy

Natural killer (NK) and NKT cells are a first line of defense against pathogens and transformed cells. However, dysregulation of their function can lead to autoimmune disease. A better understanding of the mechanisms controlling NK and NKT effector function should lead to the development of improved strategies for the treatment of many diseases. The site in which NK and NKT cells reside should be taken into account, because accumulating evidence suggests that the tissue microenvironment strongly influences their function. In this regard, the liver represents a unique immunologic organ in which the balance between the need for tolerance and the ability to respond rapidly to pathogens and tissue injury is tightly regulated. NK cells in the liver have augmented cytolytic activity as compared to other organs, which is consistent with a role for liver-associated NK cells in being critical effector cells for inhibiting tumor metastasis in the liver. Several studies also suggest that hepatic NKT cells have different functions than those in other organs. Whereas splenic and thymic NKT cells have been shown to suppress diabetes development, facilitate the induction of systemic tolerance and are regulated by IL-4 and other Th2 cytokines, certain subsets of NKT cells in the liver are important sources of Th1 cytokines such as Interferon gamma, and are the primary mediators of anti-tumor responses. The unique properties and roles as critical effector cells make NK and NKT cells within the liver microenvironment attractive targets of immunotherapeutic approaches that have the goal of controlling tumor metastasis in the liver.

Autoimmune myocarditis: past, present and future

Heart failure has become an increasingly prevalent disorder with considerable morbidity and mortality. While many causal mechanisms such as inherited cardiomyopathies, ischemic cardiomyopathy or muscular overload are easily identified in clinical practice, the molecular mechanisms that determine the progression of heart failure or ventricular remodelling are largely unknown. Autoimmune responses and inflammation are involved in the pathogenesis of many cardiovascular diseases. There is compelling evidence that inflammatory mechanisms may contribute to progressive heart failure. Thus, myocardial infiltration of lymphocytes and mononuclear cells, increased expression of pro-inflammatory chemokines and cytokines and circulating autoantibodies are frequently observed in myocarditis and dilated cardiomyopathy. In this review we give an overview on myocarditis and describe why diagnosis and treatment of myocarditis in the clinic can be difficult. We present current animal models and describe possible experimental approaches to improve diagnosis. Finally, we give an outlook on possible drug targets by describing the latest findings in the animal models focussing on chemokines and cytokines, T cell responses and interactions, tolerance induction and the development of autoantibodies.

Allogeneic intra-bone marrow transplantation prevents rheumatoid arthritis in SKG/Jcl mice

The treatment of autoimmune diseases by allogeneic bone marrow transplantation remains a promising therapeutic avenue. However, more intensive studies on murine models are essential before application to a large number of human patients. In particular, the use of bone marrow transplantation to treat rheumatoid arthritis has been problematic. We have taken advantage of the SKG/Jcl mouse that develops a chronic T cell-mediated autoimmune disease that mimics rheumatoid arthritis which attempted to prevent the development of immunopathology in these mice by allogeneic bone marrow transplantation (BMT). In particular, we utilized our unique technology in which bone marrow cells (BMCs) of control C57BL/6J mice are directly injected into the bone marrow cavity in the tibia of SKG mice (intra-bone marrow [IBM]-BMT). As controls, SKG/Jcl mice were transplanted with whole BMCs from syngeneic SKG mice. Importantly, 12 months after IBM-BMT [B6-->SKG] demonstrated no evidence of arthritis, whereas the control [SKG-->SKG] mice demonstrated, the expected immunopathology of a rheumatoid arthritis-like condition. Further, hematolymphoid cells in [B6-->SKG] mice were reconstituted by donor-derived cells and the percentages of Treg (Foxp3+/CD4+) cells, the percentages of receptor activator of nuclear factor-kappaB ligand (RANKL)+ cells on the CD4+ T cells and the serum levels of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 were normalized in the [B6-->SKG] mice. These data suggest that IBM-BMT is a viable method of immunological manipulation that suppresses the severe joint destruction and bone absorption in SKG/Jcl mice and lends further credence to the use of this methodology in humans with intractable rheumatoid arthritis.

Separation of graft-vs.-tumor effects from graft-vs.-host disease in allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) is an increasingly widely used treatment modality in hematological malignancies. Alloreactivity mediated by donor T cells (and, in some settings, by donor natural killer cells) can produce durable immunologic control or eradication of residual malignancy after allogeneic HCT. However, graft-vs.-tumor (GVT) effects are variably effective and are often accompanied by deleterious alloreactivity against normal host tissue, manifesting as graft-vs.-host disease (GVHD). A major focus of current research in HCT is the separation of beneficial GVT effects from GVHD. Here we review a number of approaches currently under investigation to specifically augment GVT effects, including the identification of minor histocompatibility antigens (mHA), adoptive immunotherapy with tumor-specific or mHA-specific cytotoxic T lymphocytes, vaccination of the donor or recipient to stimulate tumor-specific immunity, and adoptive transfer of natural killer cells. In addition, we review strategies being investigated to specifically suppress GVHD while sparing GVT, including the manipulation and infusion of regulatory T cells, the use of novel pharmacologic and biologic agents, and the use of mesenchymal stem cells. Ultimately, advances in separation of GVT from GVHD will further enhance the potential of allogeneic HCT as a curative treatment for hematological malignancies.

Cell and gene therapy using mesenchymal stem cells (MSCs)

Mesenchymal stem cells (MSCs) are considered to be a promising platform for cell and gene therapy for a variety of diseases. First, in the field of hematopoietic stem cell transplantation, there are two applications of MSCs: 1) the improvement of stem cell engrafting and the acceleration of hematopoietic reconstitution based on the hematopoiesis-supporting ability; and 2) the treatment of severe graft-versus-host disease (GVHD) based on the immunomodulatory ability. Regarding the immunosuppressive ability, we found that nitric oxide (NO) is involved in the MSC-mediated suppression of T cell proliferation. Second, tumor-bearing nude mice were injected with luciferase-expressing MSCs. An in vivo imaging analysis showed the significant accumulation of the MSCs at the site of tumors. The findings suggest that MSCs can be utilized to target metastatic tumors and to deliver anti-cancer molecules locally. As the third application, MSCs may be utilized as a cellular vehicle for protein-supplement gene therapy. When long-term transgene expression is needed, a therapeutic gene should be introduced with a minimal risk of insertional mutagenesis. To this end, site-specific integration into the AAVS1 locus on the chromosome 19 (19q13.4) by using the integration machinery of adeno-associated virus (AAV) would be particularly valuable. There will be wide-ranging applications of MSCs to frontier medical treatments in the near future.

Hunt for pluripotent stem cell -- regenerative medicine search for almighty cell

Regenerative medicine and tissue engineering are searching for a novel stem cell based therapeutic strategy that will allow for efficient treatment or even potential replacement of damaged organs. The pluripotent stem cell (PSC), which gives rise to cells from all three germ lineages, seems to be the most ideal candidate for such therapies. PSC could be extracted from developing embryos. However, since this source of stem cells for potential therapeutic purposes remains controversial, stem cell researchers look for PSC that could be isolated from the adult tissues or generated from already differentiated cells. True PSC should possess both potential for multilineage differentiation in vitro and, more importantly, also be able to complement in vivo blastocyst development. This review will summarize current approaches and limitations to isolate PSC from adult tissues or, alternatively, to generate it by nuclear reprogramming from already differentiated somatic cells.

A novel method of bone marrow transplantation (BMT) for intractable autoimmune diseases

We have previously proposed that autoimmune diseases are hemopoietic stem cell (HSC) disorders. In this review article, we provide evidence that most age-associated diseases such as osteoporosis are mesenchymal stem cell (MSC) disorders and, based on this evidence, we propose a new concept of "stem cell disorders (SCDs)", including HSC and MSC disorders. To treat SCDs, we have recently developed a new strategy (intra-bone marrow-bone marrow transplantation: IBM-BMT) for replacing the abnormal stem cells of recipients with donor-derived normal stem cells (both HSCs and MSCs). We here show that this strategy not only can be used to treat SCDs but is also applicable to organ transplantation, since IBM-BMT can induce tolerance (full chimerism) without the need for immunosuppressants even when radiation doses as the conditioning regimen of BMT are reduced to less than 5.0 Gy x 2, which is equivalent to one shot of 8 Gy (a sublethal dose). We believe that this strategy heralds a revolution in the field of transplantation (BMT and organ transplantation) and regeneration therapy.

In vivo bioimaging using photogenic rats: fate of injected bone marrow-derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) derived from bone marrow have the capacity for self-renewal and differentiation, and can give rise to cells of a muscle, bone, fat or cartilage lineage. Based on this potential and feasibility, MSCs are expected to be used in cell therapy for human diseases. Intriguingly, MSCs migrate to various in vivo locations, including injury and tumor sites. However, their cellular fate and distribution remain unclear. In this review, we first describe the potential of a photogenic transgenic rat that expresses fluorescent and/or luminescent proteins (e.g., green fluorescent protein and luciferase), and then focus on the characteristic migration of MSCs to injury and tumor sites. In addition, we will discuss an efficient delivery method for targeting the injured site. Synergized with modern advances in optical imaging, the photogenic rat system provides innovative preclinical tools and a new platform on which to further our understanding of matters concerning stem cell biology.