Helminth mediated modulation of Type 1 diabetes (T1D)

Type 1 diabetes is increasing dramatically in incidence in the developed world. While there may be several reasons for this, improved sanitation and public health measures have altered our interactions with certain infectious agents such as helminths. There is increasing interest in the use of helminths or their products to alleviate inflammatory or allergic conditions. Using rodent models of diabetes, it has been possible to explore the therapeutic potential of both live infections as well as helminth-derived products on the development of autoimmunity. This review provides an overview of the findings from animal models and additionally explores the potential for translation to the clinic.

Genetic analysis of type 1 diabetes: embryonic stem cells as new tools to unlock biological mechanisms in type 1 diabetes

The nonobese diabetic (NOD) mouse has provided an important animal model for studying the mechanism and genetics of type 1 diabetes over the past 30 years. Arguably, the bio-breeding (BB) rat model may be an even closer phenotypic mimic of the typical human disease. A large number of distinct genetic traits which influence diabetes development have been defined through an extraordinary effort, most conspicuously in the mouse model. However, in both NOD and BB models the lack of availability of robust means for experimental genetic manipulation has restricted our understanding of the mechanisms underlying this spontaneous autoimmune disease. Recent developments in the derivation of embryonic stem (ES) cells have the potential to transform this picture. We argue here that targeting of NOD strain ES cells can bring much needed certainty to our present understanding of the genetics of type 1 diabetes in the NOD mouse. In addition, ES cells can play important roles in the future, in both the NOD mouse and BB rat models, through the generation of new tools to investigate the mechanisms by which genetic variation acts to promote diabetes.

CD4 T cells and their antigens in the pathogenesis of autoimmune diabetes

Pathogenesis of type 1 diabetes (T1D) is mediated by effector T cells and CD4 Th1 and Th17T cells have important roles in this process. While effector function of Th1 cells is well established, because of their inherent plasticity Th17 cells have been more controversial. Th17 cells contribute to pathogenicity, but several studies indicate that Th17 cells transfer disease through conversion to Th1 cells in vivo. CD4T cells are attracted to islets by β-cell antigens which include insulin and the two new autoantigens, chromogranin A and islet amyloid polypeptide, all proteins of the secretory granule. Peptides of insulin and ChgA bind to the NOD class II molecule in an unconventional manner and since autoantigenic peptides may typically bind to MHC with low affinity, it is postulated that post-translational modifications of β-cell peptides could contribute to the interaction between peptides, MHC, and the autoreactive TCR.

PD-L1 blockade overrides Salmonella typhimurium-mediated diabetes prevention in NOD mice: no role for Tregs

Increasingly, evidence suggests that there is a strong environmental component to the development of the autoimmune disease type 1 diabetes. Our previous data showed that NOD mice are protected from developing diabetes after infection with Salmonella typhimurium and there is some evidence that changes within the DC compartment play a crucial role in this protective effect. This paper further characterises this Salmonella-modulated protective phenotype. We find that, contrary to other infection-mediated models of type 1 diabetes protection, there was no expansion of Foxp3(+) Tregs. Furthermore, transcriptome analysis of DCs identified a distinct Salmonella-induced signature in which the inhibitory receptor PD-L1 was up-regulated. This was confirmed by flow cytometry. In vivo blockade of the PD1/PD-L1 interaction was found to ablate the protective function of Salmonella infection. These data provide evidence for a novel regulatory DC phenotype proficient at controlling autoreactive T cells for an extended duration in the NOD mouse model of diabetes.

Developing positive relationships with voices: a preliminary Grounded Theory

BACKGROUND

Research has been exploring the phenomenon of 'voice hearing' within a relational framework. To date, studies have paid limited attention to voice hearers who view the experience positively.

MATERIAL

Semi-structured interviews were conducted with five mental health service users and seven non-service users who had had positive experiences of hearing voices. Interview transcripts were analyzed using Grounded Theory.

CONCLUSIONS

The preliminary theory suggests that the moderation of fear and control may impact on relationships with voices. Actively engaging with voices to understand their subjective meaning may be beneficial. Promoting a positive self-concept and connecting with communities who value and accept voice-hearing experiences may be particularly important.

The S. mansoni glycoprotein ω-1 induces Foxp3 expression in NOD mouse CD4⁺ T cells

Immunization with Schistosoma mansoni soluble antigen preparations protects non-obese diabetic (NOD) mice against the development of type 1 diabetes. These preparations have long been known to induce Th2 responses in vitro and in vivo. Recently, two separate groups have reported that ω-1, a well-characterized glycoprotein in S. mansoni soluble egg antigens (SEA), which with IL-4 inducing principle of S. mansoni eggs (IPSE/α-1) is one of the two major glycoproteins secreted by live eggs, is a major SEA component responsible for this effect. We found that ω-1 induces Foxp3 as well as IL-4 expression when injected in vivo. We confirmed that ω-1 conditions DCs to drive Th2 responses and further demonstrated that ω-1 induces Foxp3(+) T cells from NOD mouse naïve T cells. In contrast, IPSE/α-1 did not drive Foxp3 responses. The in vitro development of Foxp3-expressing T cells by ω-1 was TGF-β- and retinoic acid-dependent. Our work, therefore, identifies ω-1 as an important factor for the induction of Foxp3(+) T cells by SEA in NOD mice.

Autoimmunity and inflammation: murine models and translational studies

Autoimmune and inflammatory diseases, including type 1 diabetes, multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis, constitute an important and growing public health burden. However, in many cases our understanding of disease biology is limited and available therapies vary greatly in their efficacy and safety. Animal models of autoimmune and inflammatory diseases have provided valuable tools to researchers investigating their aetiology, pathology, and novel therapeutic strategies. Although such models vary in the degree to which they reflect human autoimmune and inflammatory diseases and caution is required in the extrapolation of animal data to the clinical setting, therapeutic approaches first evaluated in established animal models, including collagen-induced arthritis, experimental autoimmune encephalomyelitis, and the nonobese diabetic mouse, have successfully progressed to clinical investigation and practice. Similarly, these models have proven useful in providing support for basic hypotheses regarding the underlying causes and pathology of autoimmune and inflammatory diseases. Here we review selected murine models of autoimmunity and inflammation and efforts to translate findings from these models into both basic insights into disease biology and novel therapeutic strategies.

Identifying potential predictors of traumatic reactions to psychotic episodes

OBJECTIVES

The experience of a psychotic episode can sometimes lead to post-traumatic stress disorder (PTSD) symptoms. The objective of the research was to identify candidate predictors of such negative reactions for future prospective study. We examined six predictors identified from the PTSD and psychosis literatures in a retrospective study: a history of previous trauma, a history of previous episodes of psychosis, perceived helplessness and uncontrollability at the time of the index psychotic episode, the content of persecutory delusions at episode and the perceived presence of crisis support after the psychotic episode.

DESIGN

The design was a cross-sectional self-report and interview study of people with recently remitted symptoms of psychosis.

METHOD

36 individuals with delusions and hallucinations that had remitted in the past year were assessed for the presence of PTSD symptoms in reaction to their most recent psychotic episode. Measures of the potential predictors were also taken at this point and associations with PTSD symptoms tested.

RESULTS

61% of the individuals with remitted positive symptoms had a reaction to their psychotic episode that was potentially severe enough to receive a PTSD diagnosis. Higher levels of PTSD symptoms were associated with all six predictors tested.

CONCLUSIONS

The study provides further evidence that negative reactions to psychotic episodes are relatively common. Clinicians may wish to assess for such symptoms. The study extended these findings by identifying a number of candidate psychological predictors of PTSD reactions such as perceptions of uncontrollability and absence of support. Prospective longitudinal studies are required to test the causal significance of these factors. More broadly, the findings indicate that traumatic stress in response to intra-psychic events such as delusions can be understood in similar ways to traumatic stress arising from physical traumas such as disasters.

Roles for TGF-beta and programmed cell death 1 ligand 1 in regulatory T cell expansion and diabetes suppression by zymosan in nonobese diabetic mice

Zymosan is a complex fungal component shown to be capable of both promoting and suppressing the development of autoimmune disorders in mice. In this study, we show that a single injection of zymosan just prior to diabetes onset can significantly delay the progression of disease in NOD mice. Zymosan treatment of NOD mice induced the production of biologically active TGF-beta from cells infiltrating the pancreas and was associated with expansion of programmed cell death 1 ligand 1(+)TGF-beta(+) macrophages and Foxp3(+) regulatory T cells in vivo. Neutralization of either TGF-beta or programmed cell death 1 ligand 1 abrogated the protective effects of zymosan. Zymosan acted through TLR2 as well as ERK and p38 MAPK to induce macrophage secretion of TGF-beta and promotion of Foxp3(+) regulatory T cells in vitro and in vivo.

Prevalence of genetic haemochromatosis and iron overload in patients attending rheumatology and joint replacement clinics

BACKGROUND & AIMS

Genetic Haemochromatosis (GH) is common in North European and Celtic populations and is associated with arthropathy. We aimed to measure the frequency of the common GH mutations (C282Y and H63D), the carrier frequency of C282Y and markers of iron overload in patients who were referred to our rheumatology and joint replacement clinics.

METHODS

Unselected patients attending these clinics were anonymously tested for the described mutations. Transferrin saturation and serum ferritin were also measured and if elevated, the patients had predictive counselling then named GH mutation testing. The carrier and mutation frequencies were also determined in 340 local controls.

RESULTS

One hundred and sixty-one unselected patients attending these clinics were studied. The C282Y mutation carrier frequency was 1 in 5.2 in patients compared with 1 in 8.1 in controls (p < 0.005). The overall mutation frequencies were similar in patients and controls. One patient was found to be a homozygous for the C282Y mutation and eight were compound heterozygotes. Seven other patients had a raised ferritin, one of whom was a C282Y heterozygote.

CONCLUSION

The C282Y carrier frequency is significantly higher in patients attending rheumatology and joint replacement clinics than in controls. Screening of these patients for GH should be considered.

Harnessing CD8(+) regulatory T cells: therapy for type 1 diabetes?

In this issue of Immunity, Tsai et al. (2010) demonstrate that low-avidity autoantigen-specific regulatory CD8(+) T cells can reverse ongoing autoimmune disease and provide insight into the mechanism by which this is achieved.

Semi-dominant X-chromosome linked learning disability with progressive ataxia, spasticity and dystonia associated with the novel MECP2 variant p.V122A: akin to the new MECP2 duplication syndrome?

A novel X-chromosome linked phenotype is reported. Three affected males had learning disability in early childhood and subsequently developed progressive ataxia, dystonia, and spasticity with death at ages 9, 14 and 19 years. Two female obligate carriers had learning difficulties with psychosis in one case. A third, possible carrier had learning difficulties and epilepsy. A family study indicates that this inherited syndrome is most likely due to an unreported MECP2 variant, p.V122A, located in the methyl binding domain of the MECP2 protein. The clinical features are similar to those present in the newly reported MECP2 duplication syndrome. Non-progressive neuropsychiatric symptoms in female relatives of a male child with learning disability, ataxia and progressive spasticity may constitute a clue to inherited, MECP2 pathogenesis.

Overcoming self-destruction in the pancreas

Type 1 diabetes (T1D) is an autoimmune disease where insulin producing pancreatic beta cells are progressively destroyed. In the absence of a cure, exogenous insulin is given to maintain glucose homeostasis. Tolerogenic strategies to halt destruction and facilitate recovery of beta cells are being explored. This disease is under polygenic control; the identification of specific candidate pathways to target for drug discovery or corrective therapy would enhance therapeutic options. Whilst islet transplantation combined with immune suppression has shown some efficacy, the availability of beta cells restricts its general use. Differentiation protocols directing cultured stem cells into pancreatic tissue are under development. The availability of embryonic stem cells from a mouse model of T1D should facilitate dissection of the causes and progression of this disease.

Type 1 diabetes development requires both CD4+ and CD8+ T cells and can be reversed by non-depleting antibodies targeting both T cell populations

Type 1 diabetes development in NOD mice appears to require both CD4(+) and CD8(+) T cells. However, there are some situations where it has been suggested that either CD4(+) or CD8(+) T cells are able to mediate diabetes in the absence of the other population. In the case of transgenic mice, this may reflect the numbers of antigen-specific T cells able to access the pancreas and recruit other cell types such as macrophages leading to a release of high concentrations of damaging cytokines. Previous studies examining the requirement for CD8(+) T cells have used antibodies specific for CD8alpha. It is known that CD8alpha is expressed not only on alphabeta T cells, but also on other cell types, including a DC population that may be critical for presenting islet antigen in the pancreatic draining lymph nodes. Therefore, we have re-examined the need for both CD4(+) and CD8(+) T cell populations in diabetes development in NOD mice using an antibody to CD8beta. Our studies indicate that by using highly purified populations of T cells and antibodies specific for CD8(+) T cells, there is indeed a need for both cell types. In accordance with some other reports, we found that CD4(+) T cells appeared to be able to access the pancreas more readily than CD8(+) T cells. Despite the ability of CD4(+) T cells to recruit CD11b class II positive cells, diabetes did not develop in the absence of CD8(+) T cells. These studies support the observation that CD8(+) T cells may be final effector cells. As both T cell populations are clearly implicated in diabetes development, we have used a combination of non-depleting antibodies to target both CD4-positive and CD8-positive cells and found that this antibody combination was able to reverse diabetes onset in NOD mice as effectively as anti-CD3 antibodies.

Non-depleting Anti-CD4 Antibody not only Prevents Onset but Resolves Sialadenitis in NOD Mice

The non-obese diabetic (NOD) mouse spontaneously develops lymphocytic infiltrates in the salivary glands (sialadenitis) and provides an useful rodent model of human Sjogren's syndrome (SS). Non-depleting anti-CD4 antibodies have been shown to ameliorate Type 1 diabetes in NOD mice and also vasculitis in MRL/lpr mice. This study shows that a short course of treatment with the non-depleting anti-CD4 monoclonal antibody, YTS 177, completely prevents salivary infiltration and reverses ongoing pathology in the salivary gland.

Schistosoma mansoni egg antigens induce Treg that participate in diabetes prevention in NOD mice

Schistosoma mansoni soluble egg antigens (SEA) profoundly regulate the infected host's immune system. We previously showed that SEA prevents type 1 diabetes in NOD mice and that splenocytes from SEA-treated mice have reduced ability to transfer diabetes to NOD.scid recipients. To further characterize the mechanism of diabetes prevention we examined the cell types involved and showed that CD25(+) T-cell depletion of splenocytes from SEA-treated donors restored their ability to transfer diabetes. Furthermore, SEA treatment increased the number and proportional representation of Foxp3(+) T cells in the pancreas of NOD mice. We have used in vitro systems to analyze the effect of SEA on the development of NOD Foxp3(+) T cells. We find that SEA can induce Foxp3 expression in naïve T cells in a TGF-beta-dependent manner. Foxp3 induction requires the presence of DC, which we also show are modified by SEA to upregulate C-type lectins, IL-10 and IL-2. Our studies show that SEA can have a direct effect on CD4(+) T cells increasing expression of TGF-beta, integrin beta8 and galectins. These effects of SEA on DC and T cells may act in synergy to induce Foxp3(+) Treg in the NOD mouse.

Open reduction and internal fixation for concomitant talar neck, talar body, and medial malleolar fractures: a case report

Fractures of the talus are rare and generally associated with severe trauma. The mechanism of injury is usually forced dorsiflexion or a fall from a height. Severe talar fractures pose a challenge for surgeons as they are often associated with complications such as avascular necrosis, collapse, malunion, secondary osteoarthritis and pain. This has led some institutions to advocate primary arthrodesis for these injuries. We report an unusual complex fracture of the talus that was successfully managed with open reduction and internal fixation. By restoring a near-normal range of motion and function to a fit, young male, the severely limiting effects of arthrodesis were avoided or at least delayed. We use this case to highlight that primary arthrodesis should only be reserved for cases that fail to respond to open reduction and internal fixation or deteriorate to the point where it is the only reasonable and justifiable alternative.

Highly purified Th17 cells from BDC2.5NOD mice convert into Th1-like cells in NOD/SCID recipient mice

Th17 cells are involved in the pathogenesis of many autoimmune diseases, but it is not clear whether they play a pathogenic role in type 1 diabetes. Here we investigated whether mouse Th17 cells with specificity for an islet antigen can induce diabetes upon transfer into NOD/SCID recipient mice. Induction of diabetes in NOD/SCID mice via adoptive transfer of Th1 cells from BDC2.5 transgenic mice was prevented by treatment of the recipient mice with a neutralizing IFN-γ-specific antibody. This result suggested a major role of Th1 cells in the induction of disease in this model of type 1 diabetes. Nevertheless, transfer of highly purified Th17 cells from BDC2.5 transgenic mice caused diabetes in NOD/SCID recipients with similar rates of onset as in transfer of Th1 cells. However, treatment with neutralizing IL-17-specific antibodies did not prevent disease. Instead, the transferred Th17 cells, completely devoid of IFN-γ at the time of transfer, rapidly converted to secrete IFN-γ in the NOD/SCID recipients. Purified Th17 cells also upregulated Tbet and secreted IFN-γ upon exposure to IL-12 in vitro and in vivo in NOD/SCID recipients. These results indicate substantial plasticity of Th17 commitment toward a Th1-like profile.

Review series on helminths, immune modulation and the hygiene hypothesis: how might infection modulate the onset of type 1 diabetes?

The development of type 1 diabetes is influenced by both genetic and environmental factors. The current rise in the incidence of diabetes is occurring more rapidly than can be accounted for by genetic change, highlighting the influence of environmental modifiers. Considerable effort has been expended to identify infectious agents that might be responsible for this rise in incidence, but no single infectious agent has been linked to this dramatic increase in type 1 diabetes. There has been increasing interest in the possibility that infections of historical importance that might have shaped our immune systems over evolutionary time may also have played a role in down-modulating some autoimmune and allergic disorders. In this review, some of the ways in which certain organisms might have influenced the onset of autoimmunity are discussed.