An autoimmune disease prevented by anti-retroviral drugs

Masao Matsuoka wins the 2011 Retrovirology Prize.     

Modulation of c-myb transcription in autoimmune disease by cyclophosphamide

This study explores the relationship between autoimmunity and the myb proto-oncogene, a gene important for T cell development. The lpr/lpr mice had very large amounts of myb RNA in the lymph node (LN) cells; but unexpectedly, they had abnormally low levels of myb RNA in the thymus, an organ normally rich in myb RNA. Mice with the gld/gld genotype had high myb RNA levels in peripheral LN, similar to lpr/lpr mice, but had normal thymic myb RNA levels. Both lpr/lpr and gld/gld mice and an AILD patient with lymphadenopathy and high myb RNA in peripheral blood cells were treated with cyclophosphamide (CY). In all cases, the CY eliminated the lymphadenopathy and corrected the abnormal myb expression. However, there were significant differences in the clinical and cellular responses to this drug. A single large dose of CY led to marked regression of the lymphadenopathy of gld/gld mice and long-term amelioration of their autoimmune syndrome. In contrast, similar treatment of lpr/lpr mice failed to alter either the lymphadenopathy or the disease process. Consistent with these clinical findings, LN myb was normalized in gld/gld mice by a single injection of CY, whereas there was no effect on myb expression in lpr/lpr mice. The AILD patient reacted much like the gld/gld mice in that myb RNA levels in the peripheral blood, and bone marrow returned to normal after only three doses of CY. The lymphadenopathy and high levels of LN myb mRNA of the lpr/lpr mice could be normalized; this occurred only after long-term treatment with CY. These events were accompanied by an increase in thymic myb mRNA from low levels. These studies have combined a molecular probe with CY therapy to provide insights into the cellular bases for lymphoproliferative autoimmune diseases.     

Multicystic autoimmune thyroiditis-like disease associated with HIV infection. A case report.

BACKGROUND: Human immunodeficiency virus (HIV) infection and resulting acquired immunodeficiency syndrome (AIDS) may involve virtually every organ system, including the endocrine glands. Thyroid dysfunction most commonly reflects advanced disease and generally resembles euthyroid sick syndrome. Rarely do opportunistic infections, hemorrhage, neoplasms and drugs account for alterations in thyroid tissue. Multiple lymphoepithelial cysts of parotid gland and thymus have been identified, but similar findings in thyroid gland have not been reported. CASE: A 41-year-old, HIV-seropositive woman, asymptomatic for seven years, developed a squamous cell carcinoma of the cervix with local-regional extension. At the same time, bilateral complex thyroid cysts and high titers of antimicrosomal antibodies (1/6,400) were detected. Ultrasound-guided fine needle aspiration biopsy of the thyroid showed a heterogeneous lymphocytic population with a reactive appearance and occasional groups of epithelial cells with an immature squamous pattern, along with cytologic features of autoimmune thyroiditis. Immunocytochemistry was positive for CD20, CD3 and CD5. Immunoglobulin heavy chain gene rearrangement by polymerase chain reaction from cytologic material showed a polyclonal lymphoid population. External radiotherapy resulted in a significant reduction in the pelvic lesion. Four months after diagnosis, abdominal ultrasound displayed multiple hepatic metastasis, the patient's condition rapidly deteriorated, and she died about a month later. CONCLUSION: This case had unique features and probably represented an AIDS-related lesion and distinct entity.     

Multistep pathogenesis of autoimmune disease

In the immune system, many tolerance checkpoints exist to prevent self-antigens from stimulating the relentless growth of self-reactive B and T lymphocytes. The genes and molecular pathways underpinning these checkpoints overlap with those involved in tumor suppression. As with an inherited predisposition to cancer, inherited defects in self-tolerance genes typically precipitate autoimmune disease stochastically after a latent phase. Multiple mutations, inherited and somatic, may be needed before a self-reactive clone bypasses sequential tolerance checkpoints resulting in the emergence of autoimmune disease.     

Amplification and transport of an endemic fish disease by an introduced species

The introduction of American shad from the Atlantic to the Pacific coast of North America in the late 1800’s and the subsequent population expansion in the 1980’s resulted in the amplification of Ichthyophonus sp., a Mesomycetozoean parasite of wild marine fishes. Sequence analysis of the ribosomal DNA gene complex (small subunit and internal transcribed spacer regions) and Ichthyophonus epidemiological characteristics indicate a low probability that Ichthyophonus was co-introduced with American shad from the Atlantic; rather, Ichthyophonus was likely endemic to marine areas of the Pacific region and amplified by the expanding population of a highly susceptible host species. The migratory life history of shad resulted in the transport of amplified Ichthyophonus from its endemic region in the NE Pacific to the Columbia River watershed. An Ichthyophonus epizootic occurred among American shad in the Columbia River during 2007, when infection prevalence was 72%, and 57% of the infections were scored as moderate or heavy intensities. The epizootic occurred near the record peak of shad biomass in the Columbia River, and corresponded to an influx of 1,595 mt of infected shad tissues into the Columbia River. A high potential for parasite spillback and the establishment of a freshwater Ichthyophonus life cycle in the Columbia River results from currently elevated infection pressures, broad host range, plasticity in Ichthyophonus life history stages, and precedents for establishment of the parasite in other freshwater systems. The results raise questions regarding the risk for sympatric salmonids and the role of Ichthyophonus as a population-limiting factor affecting American shad in the Columbia River.     

Comparison of antibody repertoires produced by HIV-1 infection, other chronic and acute infections, and systemic autoimmune disease

Background

Antibodies (Abs) produced during HIV-1 infection rarely neutralize a broad range of viral isolates; only eight broadly-neutralizing (bNt) monoclonal (M)Abs have been isolated. Yet, to be effective, an HIV-1 vaccine may have to elicit the essential features of these MAbs. The V genes of all of these bNt MAbs are highly somatically mutated, and the V_H genes of five of them encode a long (≥20 aa) third complementarity-determining region (CDR-H3). This led us to question whether long CDR-H3s and high levels of somatic mutation (SM) are a preferred feature of anti-HIV bNt MAbs, or if other adaptive immune responses elicit them in general.

Methodology and Principal Findings

We assembled a V_H-gene sequence database from over 700 human MAbs of known antigen specificity isolated from chronic (viral) infections (ChI), acute (bacterial and viral) infections (AcI), and systemic autoimmune diseases (SAD), and compared their CDR-H3 length, number of SMs and germline V_H-gene usage. We found that anti-HIV Abs, regardless of their neutralization breadth, tended to have long CDR-H3s and high numbers of SMs. However, these features were also common among Abs associated with other chronic viral infections. In contrast, Abs from acute viral infections (but not bacterial infections) tended to have relatively short CDR-H3s and a low number of SMs, whereas SAD Abs were generally intermediate in CDR-H3 length and number of SMs. Analysis of V_H gene usage showed that ChI Abs also tended to favor distal germline V_H-genes (particularly V_H1-69), especially in Abs bearing long CDR-H3s.

Conclusions and Significance

The striking difference between the Abs produced during chronic vs. acute viral infection suggests that Abs bearing long CDR-H3s, high levels of SM and V_H1-69 gene usage may be preferentially selected during persistent infection.     

Amplification of tick-borne encephalitis virus infection during co-feeding of ticks

Abstract. Following engorgement of Rhipicephalus appendiculatus larvae on guinea-pigs infected with tick-borne encephalitis (TBE) virus, none of the engorged larvae or emergent nymphs contained detectable infectious virus. However, one of twelve pools, each containing three of the unfed nymphs, was positive when screened by polymerase chain reaction (PCR), indicating a low prevalence of TBE virus infection in the unfed nymphs. After engorgement of the nymphs on four uninfected guinea-pigs, 19/24 (79%) fed nymphs from one guinea-pig and 4/25 (16%) fed nymphs from a second guinea-pig were infected; all the ticks examined from the other two guinea-pigs were uninfected. The results suggest that TBE virus was transmitted from a low proportion of infected nymphs (infected as larvae) to uninfected nymphs as they fed together on an uninfected guinea-pig. Such amplification of the initial infection, at the population level, could play an important role in maintaining TBE virus infections in nature, particularly if there is a low level of vertical transmission from one tick generation to the next.     

T-cell metabolism in autoimmune disease

Cancer cells have long been known to fuel their pathogenic growth habits by sustaining a high glycolytic flux, first described almost 90 years ago as the so-called Warburg effect. Immune cells utilize a similar strategy to generate the energy carriers and metabolic intermediates they need to produce biomass and inflammatory mediators. Resting lymphocytes generate energy through oxidative phosphorylation and breakdown of fatty acids, and upon activation rapidly switch to aerobic glycolysis and low tricarboxylic acid flux. T cells in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have a disease-specific metabolic signature that may explain, at least in part, why they are dysfunctional. RA T cells are characterized by low adenosine triphosphate and lactate levels and increased availability of the cellular reductant NADPH. This anti-Warburg effect results from insufficient activity of the glycolytic enzyme phosphofructokinase and differentiates the metabolic status in RA T cells from those in cancer cells. Excess production of reactive oxygen species and a defect in lipid metabolism characterizes metabolic conditions in SLE T cells. Owing to increased production of the glycosphingolipids lactosylceramide, globotriaosylceramide and monosialotetrahexosylganglioside, SLE T cells change membrane raft formation and fail to phosphorylate pERK, yet hyperproliferate. Borrowing from cancer metabolomics, the metabolic modifications occurring in autoimmune disease are probably heterogeneous and context dependent. Variations of glucose, amino acid and lipid metabolism in different disease states may provide opportunities to develop biomarkers and exploit metabolic pathways as therapeutic targets.     

Pepsin and autoimmune disease mouse

The effects of pepsin on autoimmune glomerulonephritis of MRL/1 mice were investigated. Intravenous administration of pepsin significantly improved survival rate and suppressed progressive increase in urinary excretion of protein and various histopathological changes in kidney. Increased serum levels of immune complex and anti-DNA antibody in MRL/1 mice were decreased by pepsin. Pepsin ameliorated abnormalities in lymphocyte subsets and lymphocyte functions. The fact that pepsin ameliorated abnormalities in immune function may contribute to the preventive effects of pepsin against pathogenesis and progress of immune complex nephritis.     

Proteomic biomarkers for autoimmune disease

Autoimmune diseases affect 3% of the world population, yet the diagnosis and classification of autoimmune diseases remain based on clinical examination combined with traditional laboratory tests and imaging studies. The development of genomic and proteomic technologies provides an unprecedented ability to identify novel biosignatures to diagnose, classify, and guide therapeutic decision making in patients with autoimmune disease. In this article, we review recent advances in proteomics technologies and their application to autoimmune disease.     

Animal models of autoimmune liver disease

Autoimmune liver diseases in humans are characterized by chronic active hepatitis with serum autoantibodies, hypergammaglobulinemia and liver pathology showing necroinflammatory disease and fibrosis. There are an increasing number of autoantigens believed to be associated with various autoimmune liver diseases. This review will briefly outline human autoimmune hepatitis and the immunology of the liver. Various murine models of liver inflammation will be discussed, including transgenic and non-transgenic models, with emphasis on how these models aid in our knowledge of the mechanisms of disease development and chronicity. There are limitations with all of the models, including a preponderance of T-cell-focused responses. Murine models do not easily develop fibrosis, a hallmark of autoimmune hepatitis in humans. Different experimental models may not reach the same conclusions with differences between immune responses. However, this multiplicity of responses does not necessarily imply that these models are inappropriate for the study of liver immunology and autoimmune liver diseases, as different autoantigens may induce different liver responses. Knowledge of how the liver differs from other immune organs is essential to further our understanding of liver-specific autoimmunity. The plethora of antigens implicated in autoimmune hepatitis in humans predicts that multiple mechanisms may play a role in precipitating disease in the susceptible individual.     

Organ-specific autoimmune disease induced in mice by elimination of T cell subsets. V. Neonatal administration of cyclosporin A causes autoimmune disease

Cyclosporin A (CsA), a potent immunosuppressive drug, caused organ-specific autoimmune disease, such as gastritis with anti-parietal cell autoantibodies or oophoritis with anti-oocyte autoantibodies, in BALB/c mice when the drug was administered daily for 1 wk to newborns. Administration to adult mice did not. CsA abrogated the production of L3T4+ T cells and Lyt-2+ T cells in the thymus. Consequently, these T cells were substantially depleted from the peripheral lymphoid organs, especially when the drug was administered from the day of birth. Autoimmune disease was prevented when CsA-treated newborn mice were inoculated with splenic T cells from normal syngeneic mice. However, removal of the thymus immediately after neonatal CsA treatment produced autoimmune disease with a higher incidence and in a wider spectrum of organs, i.e., thyroiditis, sialoadenitis of the salivary gland, gastritis, insulitis of the endocrine pancreas, adrenalitis, oophoritis, or orchitis. Each autoimmune disease was accompanied by the development of circulating autoantibodies specific for the corresponding organ Ag. Immunopathology of these autoimmune diseases was quite similar to that of human organ-specific autoimmune diseases.     

Amplification by enzymatic cycling

Summary Enzymatic cycling provides a methodology for virtually unlimited amplification of analytical sensitivity. The most widely applicable cycling systems are those for NAD and NADP, since these can be used to increase the sensitivity of methods for a host of other substances. However, cycling systems for ATP plus ADP, GTP+ GDP, glutathione and coenzyme A have also proven tb be very useful.A total of 19 cycling procedures are described in greater or lesser detail. Some of these are capable of amplification rates in excess of 20,000 per hour in a single cycling step (20,000 × 20,000 with two one hour cycling steps). Advantages, disadvantages, limitations and other practical considerations are stressed, as well as the means for coupling the cycling systems to assays for other substances.     

Taenia crassiceps infection abrogates experimental autoimmune encephalomyelitis

Helminth infections induce strong immunoregulation that can modulate subsequent pathogenic challenges. Taenia crassiceps causes a chronic infection that induces a Th2-biased response and modulates the host cellular immune response, including reduced lymphoproliferation in response to mitogens, impaired antigen presentation and the recruitment of suppressive alternatively activated macrophages (AAMФ). In this study, we aimed to evaluate the ability of T. crassiceps to reduce the severity of experimental autoimmune encephalomyelitis (EAE). Only 50% of T. crassiceps-infected mice displayed EAE symptoms, which were significantly less severe than uninfected mice. This effect was associated with both decreased MOG-specific splenocyte proliferation and IL-17 production and limited leukocyte infiltration into the spinal cord. Infection with T. crassiceps induced an anti-inflammatory cytokine microenvironment, including decreased TNF-α production and high MOG-specific production of IL-4 and IL-10. While the mRNA expression of TNF-α and iNOS was lower in the brain of T. crassiceps-infected mice with EAE, markers for AAMФ were highly expressed. Furthermore, in these mice, there was reduced entry of CD3⁺Foxp3⁻ cells into the brain. The T. crassiceps-induced immune regulation decreased EAE severity by dampening T cell activation, proliferation and migration to the CNS.     

Experimental autoimmune orchitis: in vitro induction of an autoimmune disease.

Experimental autoimmune orchitis (EAO) can be induced in vitro. Normal lymph node lymphocytes cultured with autologous dissociated testis cells form rosette-like aggregates and later undergo blast transformation and proliferation. These stimulated lymphocytes cause in vivo EAO lesions, when injectd into syngeneic recipients. Moreover, their autoimmune reactivity can be monitored by an in vitro cytostasis assay. Density gradient analysis of the early lymphocyte-testis cultures reveals that the autoimmune reactive lymphocytes are enriched in the rosette populations. It therefore appears that testicular self-antigens are recognized by clonally preformed autologous lymphocytes.     

Conversion of monophasic to recurrent autoimmune disease by autoreactive T cell subsets

Autoimmune uveitis has been elicited in susceptible rodents by several ocular-specific Ags. In most of these animal models the induced uveitis is acute and monophasic. Because recurrent uveitis poses the highest risk for blinding ocular complications in human disease, a spontaneous relapsing animal model would be most helpful in understanding the disease pathogenesis. In our current study we have observed that the adoptive transfer of interphotoreceptor retinoid-binding protein residues 1177-1191-specific T cells to naive Lewis rats induced a chronic relapsing disease, in contrast to the monophasic disease induced by immunization with interphotoreceptor retinoid-binding protein residues 1177-1191 emulsified in CFA. The chronic relapsing uveitis induced by autoreactive T cell subsets is dependent on the number of autoreactive T cells generated as well as their activation status. Our study documented a spontaneous model of recurrent uveitis in the rat, which should assist us in the study of disease pathogenesis and the design of specific therapy.     

Toll-like receptors in systemic autoimmune disease

Toll-like receptors (TLRs) have a crucial role in the early detection of pathogen-associated molecular patterns and the subsequent activation of the adaptive immune response. Whether TLRs also have an important role in the recognition of endogenous ligands has been more controversial. Numerous in vitro studies have documented activation of both autoreactive B cells and plasmacytoid dendritic cells by mammalian TLR ligands. The issue of whether these in vitro observations translate to an in vivo role for TLRs in either the initiation or the progression of systemic autoimmune disease is a subject of intense research; data are beginning to emerge showing that this is the case.