Circulating ß cell-specific CD8+ T cells restricted by high-risk HLA class I molecules show antigen experience in children with and at risk of type 1 diabetes.

In type 1 diabetes (T1D), autoreactive cytotoxic CD8+ T cells are implicated in the destruction of insulin-producing ß cells. The HLA-B*3906 and HLA-A*2402 class I genes confer increased risk and promote early disease onset, suggesting that CD8+ T cells that recognize peptides presented by these class I molecules on pancreatic ß cells play a pivotal role in the autoimmune response. We examined the frequency and phenotype of circulating preproinsulin (PPI)-specific and insulin B (InsB)-specific CD8+ T cells in HLA-B*3906+ children newly diagnosed with T1D and in high-risk HLA-A*2402+ children before the appearance of disease-specific autoantibodies and before diagnosis of T1D. Antigen-specific CD8+ T cells were detected using human leucocyte antigen (HLA) class I tetramers and flow cytometry was used to assess memory status. In HLA-B*3906+ children with T1D, we observed an increase in PPI5-12 -specific transitional memory CD8+ T cells compared to non-diabetic, age- and HLA-matched subjects. Furthermore, PPI5-12 -specific CD8+ T cells in HLA-B*3906+ children with T1D showed a significantly more antigen-experienced phenotype compared to polyclonal CD8+ T cells. In longitudinal samples from high-risk HLA-A*2402+ children, the percentage of terminal effector cells within the InsB15-24 -specific CD8+ T cells was increased before diagnosis relative to samples taken before the appearance of autoantibodies. This is the first study, to our knowledge, to report HLA-B*3906-restricted autoreactive CD8+ T cells in T1D. Collectively, our results provide evidence that ß cell-reactive CD8+ T cells restricted by disease-associated HLA class I molecules display an antigen-experienced phenotype and acquire enhanced effector function during the period leading to clinical diagnosis, implicating these cells in driving disease.

ß-cell specific T-lymphocyte response has a distinct inflammatory phenotype in children with Type 1 diabetes compared with adults.

AIM: To examine the hypothesis that the quality, magnitude and breadth of helper T-lymphocyte responses to ß cells differ in Type 1 diabetes according to diagnosis in childhood or adulthood. METHODS: We studied helper T-lymphocyte reactivity against ß-cell autoantigens by measuring production of the pro-inflammatory cytokine interferon-γ and the anti-inflammatory cytokine interleukin-10, using enzyme-linked immunospot assays in 61 people with Type 1 diabetes (within 3 months of diagnosis, positive for HLA DRB1*0301 and/or *0401), of whom 33 were children/adolescents, and a further 91 were unaffected siblings. RESULTS: Interferon-γ responses were significantly more frequent in children with Type 1 diabetes compared with adults (85 vs 61%; P = 0.04). Insulin and proinsulin peptides were preferentially targeted in children (P = 0.0001 and P = 0.04, respectively) and the breadth of the interferon-γ response was also greater, with 70% of children having an interferon-γ response to three or more peptides compared with 14% of adults (P < 0.0001). Islet ß-cell antigen-specific interleukin-10 responses were similar in children and adults in terms of frequency, breadth and magnitude, with the exception of responses to glutamic acid decarboxylase 65, which were significantly less frequent in adults. CONCLUSIONS: At diagnosis of Type 1 diabetes, pro-inflammatory autoreactivity is significantly more prevalent, focuses on a wider range of targets, and is more focused on insulin/proinsulin in children than adults. We interpret this as indicating a more aggressive immunological response in the younger age group that is especially characterized by loss of tolerance to proinsulin. These findings highlight the existence of age-related heterogeneity in Type 1 diabetes pathogenesis that could have relevance to the development of immune-based therapies.

Stimulated urine C-peptide creatinine ratio vs serum C-peptide level for monitoring of ß-cell function in the first year after diagnosis of Type 1 diabetes.

AIMS: To determine if urine C-peptide/creatinine ratio is a useful tool for monitoring ß-cell function in new-onset Type 1 diabetes. METHODS: Data were obtained from a prospective immunomodulation study in people with Type 1 diabetes ≤ 3 months from diagnosis, with a standard mixed-meal tolerance test and measurement of urine C-peptide/creatinine ratio carried out at 0, 3, 6, 9 and 12 months. The change in the insulin-dose-adjusted HbA1c level was also correlated with the change in serum/urine C-peptide level during the 12-month follow-up period. RESULTS: A significant reduction in urine C-peptide/creatinine ratio, measured after a mixed-meal, was reached at 9 months (-45.4%), whilst the reduction in stimulated serum C-peptide level reached significance after 3 months (-54.7%) in placebo-treated participants. Neither change in stimulated serum C-peptide nor change in urine C-peptide level correlated with each other, and nor did change in insulin-dose-adjusted HbA1c level in the first 6 months, but all measures correlated significantly in the second half of the 12-month follow-up period. CONCLUSION: Mixed-meal-stimulated urine C-peptide/creatinine ratio was similar to, although less sensitive than, stimulated serum C-peptide level in monitoring ß-cell function during the first year after diagnosis. Because the former is significantly less invasive, it warrants inclusion in further studies in Type 1 diabetes and may represent an attractive alternative outcome measure in cohort studies and in children.

Proinsulin multi-peptide immunotherapy induces antigen-specific regulatory T cells and limits autoimmunity in a humanized model.

Peptide immunotherapy (PIT) is a targeted therapeutic approach, involving administration of disease-associated peptides, with the aim of restoring antigen-specific immunological tolerance without generalized immunosuppression. In type 1 diabetes, proinsulin is a primary antigen targeted by the autoimmune response, and is therefore a strong candidate for exploitation via PIT in this setting. To elucidate the optimal conditions for proinsulin-based PIT and explore mechanisms of action, we developed a preclinical model of proinsulin autoimmunity in a humanized HLA-DRB1*0401 transgenic HLA-DR4 Tg mouse. Once proinsulin-specific tolerance is broken, HLA-DR4 Tg mice develop autoinflammatory responses, including proinsulin-specific T cell proliferation, interferon (IFN)-γ and autoantibody production. These are preventable and quenchable by pre- and post-induction treatment, respectively, using intradermal proinsulin-PIT injections. Intradermal proinsulin-PIT enhances proliferation of regulatory [forkhead box protein 3 (FoxP3(+))CD25(high) ] CD4 T cells, including those capable of proinsulin-specific regulation, suggesting this as its main mode of action. In contrast, peptide delivered intradermally on the surface of vitamin D3-modulated (tolerogenic) dendritic cells, controls autoimmunity in association with proinsulin-specific IL-10 production, but no change in regulatory CD4 T cells. These studies define a humanized, translational model for in vivo optimization of PIT to control autoimmunity in type 1 diabetes and indicate that dominant mechanisms of action differ according to mode of peptide delivery.

A distinct immunogenic region of glutamic acid decarboxylase 65 is naturally processed and presented by human islet cells to cytotoxic CD8 T cells.

CD8 T cells specific for islet autoantigens are major effectors of ß cell damage in type 1 diabetes, and measurement of their number and functional characteristics in blood represent potentially important disease biomarkers. CD8 T cell reactivity against glutamic acid decarboxylase 65 (GAD65) in HLA-A*0201 subjects has been reported to focus on an immunogenic region 114-123 (VMNILLQYVV), with studies demonstrating both 114-123 and 114-122 epitopes being targeted. However, the fine specificity of this response is unclear and the key question as to which epitope(s) ß cells naturally process and present and, therefore, the pathogenic potential of CD8 T cells with different specificities within this region has not been addressed. We generated human leucocyte antigen (HLA)-A*0201-restricted CD8 T cell clones recognizing either 114-122 alone or both 114-122 and 114-123. Both clone types show potent and comparable effector functions (cytokine and chemokine secretion) and killing of indicator target cells externally pulsed with cognate peptide. However, only clones recognizing 114-123 kill target cells transfected with HLA-A*0201 and GAD2 and HLA-A*0201(+) human islet cells. We conclude that the endogenous pathway of antigen processing by HLA-A*0201-expressing cells generates GAD65114-123 as the predominant epitope in this region. These studies highlight the importance of understanding ß cell epitope presentation in the design of immune monitoring for potentially pathogenic CD8 T cells.

Characterization of the autoimmune response against the nerve tissue S100ß in patients with type 1 diabetes.

Type 1 diabetes results from destruction of insulin-producing beta cells in pancreatic islets and is characterized by islet cell autoimmunity. Autoreactivity against non-beta cell-specific antigens has also been reported, including targeting of the calcium-binding protein S100ß. In preclinical models, reactivity of this type is a key component of the early development of insulitis. To examine the nature of this response in type 1 diabetes, we identified naturally processed and presented peptide epitopes derived from S100ß, determined their affinity for the human leucocyte antigen (HLA)-DRB1*04:01 molecule and studied T cell responses in patients, together with healthy donors. We found that S100ß reactivity, characterized by interferon (IFN)-γ secretion, is a characteristic of type 1 diabetes of varying duration. Our results confirm S100ß as a target of the cellular autoimmune response in type 1 diabetes with the identification of new peptide epitopes targeted during the development of the disease, and support the preclinical findings that autoreactivity against non-beta cell-specific autoantigens may have a role in type 1 diabetes pathogenesis.

Multi-parametric flow cytometric and genetic investigation of the peripheral B cell compartment in human type 1 diabetes.

The appearance of circulating islet-specific autoantibodies before disease diagnosis is a hallmark of human type 1 diabetes (T1D), and suggests a role for B cells in the pathogenesis of the disease. Alterations in the peripheral B cell compartment have been reported in T1D patients; however, to date, such studies have produced conflicting results and have been limited by sample size. In this study, we have performed a detailed characterization of the B cell compartment in T1D patients (n = 45) and healthy controls (n = 46), and assessed the secretion of the anti-inflammatory cytokine interleukin (IL)-10 in purified B cells from the same donors. Overall, we found no evidence for a profound alteration of the B cell compartment or in the production of IL-10 in peripheral blood of T1D patients. We also investigated age-related changes in peripheral B cell subsets and confirmed the sharp decrease with age of transitional CD19(+) CD27(-) CD24(hi) CD38(hi) B cells, a subset that has recently been ascribed a putative regulatory function. Genetic analysis of the B cell compartment revealed evidence for association of the IL2-IL21 T1D locus with IL-10 production by both memory B cells (P = 6·4 × 10(-4) ) and islet-specific CD4(+) T cells (P = 2·9 × 10(-3) ). In contrast to previous reports, we found no evidence for an alteration of the B cell compartment in healthy individuals homozygous for the non-synonymous PTPN22 Trp(620) T1D risk allele (rs2476601; Arg(620) Trp). The IL2-IL21 association we have identified, if confirmed, suggests a novel role for B cells in T1D pathogenesis through the production of IL-10, and reinforces the importance of IL-10 production by autoreactive CD4(+) T cells.

Comparison of peptide-major histocompatibility complex tetramers and dextramers for the identification of antigen-specific T cells.

Fluorochrome-conjugated peptide-major histocompatibility complex (pMHC) multimers are widely used for flow cytometric visualization of antigen-specific T cells. The most common multimers, streptavidin-biotin-based 'tetramers', can be manufactured readily in the laboratory. Unfortunately, there are large differences between the threshold of T cell receptor (TCR) affinity required to capture pMHC tetramers from solution and that which is required for T cell activation. This disparity means that tetramers sometimes fail to stain antigen-specific T cells within a sample, an issue that is particularly problematic when staining tumour-specific, autoimmune or MHC class II-restricted T cells, which often display TCRs of low affinity for pMHC. Here, we compared optimized staining with tetramers and dextramers (dextran-based multimers), with the latter carrying greater numbers of both pMHC and fluorochrome per molecule. Most notably, we find that: (i) dextramers stain more brightly than tetramers; (ii) dextramers outperform tetramers when TCR-pMHC affinity is low; (iii) dextramers outperform tetramers with pMHC class II reagents where there is an absence of co-receptor stabilization; and (iv) dextramer sensitivity is enhanced further by specific protein kinase inhibition. Dextramers are compatible with current state-of-the-art flow cytometry platforms and will probably find particular utility in the fields of autoimmunity and cancer immunology.

Identification and characterisation of peptide binding motifs of six autoimmune disease-associated human leukocyte antigen-class I molecules including HLA-B*39:06.

Research on CD8 T cell-mediated inflammatory diseases requires a better understanding of target epitopes and the constraints placed upon these by major histocompatibility complex (MHC) class I binding restrictions, especially those that relate to predisposing alleles. We used linear trap quadrupole fourier transform (LTQ-FT) tandem mass spectrometry to identify naturally processed and presented peptides eluted from the MHC-negative myeloid leukaemia cell line K562 transfected with specific MHC class I genes. We provide information on the peptidome of HLA-B*39:06, which is associated with the autoimmune disease type 1 diabetes, and extend the analysis to include a further five human leukocyte antigen (HLA) alleles (HLA-A*02:01/-A*11:01/-A*24:02/-B*18:01/-B*38:01) studied under identical experimental conditions. We identified a total of 3095 individual peptides with a mascot score ≥40 (HLA-A*02:01 = 569 peptides, -A*11:01 = 904, A*24:02 = 257, -B*18:01 = 615, -B*38:01 = 453, -B*39:06 = 297). Peptides had a preferential length of nine amino acids and originated mainly from cytoplasmic or nuclear proteins. Eluted peptides revealed a strong binding motif with binding anchor positions at position 2 (P2) and the C-terminus (PΩ). Peptides eluted from HLA-A*02:01 showed a P2 preference for leucine (62% of total peptides have Leu at P2) and PΩ preference for valine (49%). Similar data are provided for HLA-A*11:01 (P2:Thr, 29%; PΩ:Lys, 49%), -A*24:02 (P2:Tyr, 78%; PΩ:Phe, 41%), -B*18:01 (P2:Glu, 77%; PΩ:Tyr, 32%), -B*38:01 (P2:His, 51%; PΩ:Leu, 45%) and -B*39:06 (P2:Arg/His, 24%; PΩ:Ala, 64%). This work thus gives an overview of the naturally processed and presented repertoire of several common and autoimmune disease-related HLA alleles, which may be useful in studying autoreactive CD8 T cell responses and the role of HLA in disease susceptibility.

Prevalence of anti-N-methyl-D-aspartate (NMDA) receptor [corrected] antibodies in patients with schizophrenia and related psychoses: a systematic review and meta-analysis.

BACKGROUND: Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoimmune condition caused by immunoglobulin (Ig)G antibodies directed against the NR1 subunit of the NMDA glutamate receptor. Approximately 65% of cases present with psychiatric symptoms, particularly psychosis. It remains to be established whether anti-NMDA receptor antibodies can cause a 'purely' psychotic illness without overt neurological symptoms. METHOD: We conducted a systematic literature search to establish what proportion of patients with schizophrenia and related psychoses have antibodies directed against the NMDA receptor. Studies were included if (a) subjects had a diagnosis of schizophrenia, schizophrenia spectrum disorder or first-episode psychosis (FEP) using standard criteria, (b) serum was analysed for the presence of anti-NMDA receptor antibodies; and (c) the purpose of the study was to look for the presence of anti-NMDA receptor antibodies in patients with a primary psychiatric diagnosis without clinical signs of encephalitis. RESULTS: Seven studies were included, comprising 1441 patients, of whom 115 [7.98%, 95% confidence interval (CI) 6.69-9.50] were anti-NMDA receptor antibody positive. Of these, 21 (1.46%, 95% CI 0.94-2.23) patients were positive for antibodies of the IgG subclass. Prevalence rates were greater in cases than controls only for IgG antibodies; other subclasses are of less certain aetiological relevance. There was significant heterogeneity in terms of patient characteristics and the antibody assay used. CONCLUSIONS: A minority of patients with psychosis are anti-NMDA receptor antibody positive. It remains to be established whether this subset of patients differs from antibody-negative patients in terms of underlying pathology and response to antipsychotic treatment, and whether immunomodulatory treatments are effective in alleviating psychotic symptoms in this group.

Progress in immune-based therapies for type 1 diabetes.

Immune-based therapies that prevent type 1 diabetes or preserve metabolic function remaining at diagnosis have become a major objective for funding agencies and international trial consortia, and receive backing from notable patient advocate groups. The development of immune-based therapeutic strategies in this arena requires a careful balancing of the risks of the therapy against the potential benefits, because many individuals are diagnosed or identified as being at increased risk of disease in early childhood, a period when manipulation of the developing immune system should be undertaken with caution. In addition, a therapy exists (daily insulin injection) that is life-saving in the acute stages of disease and can be used effectively over a lifetime as maintenance. Conversely, the disease is increasing in incidence; is peaking in ever-younger age groups; carries significant risk of increased morbidity and early mortality; and remains difficult to manage effectively in many settings. With these issues in mind, in this article we review progress towards immune-based strategies for this chronic autoimmune disease.

Immunological pathways to ß-cell damage in Type 1 diabetes.

Following almost 30 years of intensive research, initiated by the observation that Type 1 diabetes development is associated with a characteristic pancreatic immune cell infiltrate, a picture is emerging of which of the diverse effector arms of the immune system are involved in ß-cell destruction. Like any chronic pathology, there is considerable complexity, and our ability to model the disease is hampered by a lack of ready access to the target organ and limited longitudinal analyses. However, it seems that putative pathways can start to be ruled in and out, in part as a result of focused mechanistic studies that make use of new technologies, and in part through analysis of the outcomes of clinical trials of new agents aimed at halting the disease process. The picture that emerges suggests a pathway to prevention that may require combinations of therapeutic agents that target different aspects of the immune system and will need to be used with due attention to their risk-benefit profiles.

Broadening the translational immunology landscape.

It is just over 5 years since Clinical and Experimental Immunology came under the direction of a new team of Editors and made a concerted effort to refresh its approach to promoting clinical and applied immunology through its pages. There were two major objectives: to foster papers in a field which, at the time, we loosely termed 'translational immunology'; and to create a forum for the presentation and discussion of immunology that is relevant to clinicians operating in this space. So, how are we doing with these endeavours? This brief paper aims to summarize some of the key learning points and successes and highlight areas in which translational gaps remain.

Antibody combination therapy targeting CD25, CD70 and CD8 reduces islet inflammation and improves glycaemia in diabetic mice.

Destruction of pancreatic islets in type 1 diabetes is caused by infiltrating, primed and activated T cells. In a clinical setting this autoimmune process is already in an advanced stage before intervention therapy can be administered. Therefore, an effective intervention needs to reduce islet inflammation and preserve any remaining islet function. In this study we have investigated the role of targeting activated T cells in reversing autoimmune diabetes. A combination therapy consisting of CD25-, CD70- and CD8-specific monoclonal antibodies was administered to non-obese diabetic (NOD) mice with either new-onset diabetes or with advanced diabetes. In NOD mice with new-onset diabetes antibody combination treatment reversed hyperglycaemia and achieved long-term protection from diabetes (blood glucose <13·9 mmol/l) in >50% of mice. In contrast, in the control, untreated group blood glucose levels continued to increase and none of the mice were protected from diabetes (P < 0·0001). Starting therapy early when hyperglycaemia was relatively mild proved critical, as the mice with advanced diabetes showed less efficient control of blood glucose and shorter life span. Histological analysis (insulitis score) showed islet preservation and reduced immune infiltration in all treated groups, compared to their controls. In conclusion, antibody combination therapy that targets CD25, CD70 and CD8 results in decreased islet infiltration and improved blood glucose levels in NOD mice with established diabetes.

Developing combination immunotherapies for type 1 diabetes: recommendations from the ITN-JDRF Type 1 Diabetes Combination Therapy Assessment Group.

Like many other complex human disorders of unknown aetiology, autoimmune-mediated type 1 diabetes may ultimately be controlled via a therapeutic approach that combines multiple agents, each with differing modes of action. The numerous advantages of such a strategy include the ability to minimize toxicities and realize synergies to enhance and prolong efficacy. The recognition that combinations might offer far-reaching benefits, at a time when few single agents have yet proved themselves in well-powered trials, represents a significant challenge to our ability to conceive and implement rational treatment designs. As a first step in this process, the Immune Tolerance Network, in collaboration with the Juvenile Diabetes Research Foundation, convened a Type 1 Diabetes Combination Therapy Assessment Group, the recommendations of which are discussed in this Perspective paper.

Level of major histocompatibility complex class I expression on endothelium in non-obese diabetic mice influences CD8 T cell adhesion and migration.

An important prerequisite for development of insulitis and beta-cell destruction in type 1 diabetes is successful transmigration of autoreactive T cells across the islet endothelium. Previous work suggests that antigen presentation to T cells by endothelium, which requires endothelial cell expression of major histocompatibility complex (MHC) molecules, promotes tissue-specific T cell migration. We therefore tested the hypothesis that the level of endothelial MHC class I molecule expression in diabetes-prone mice directly influences autoreactive CD8 T cell migration. We investigated the immune phenotype of endothelial cells, focusing on endothelial MHC class I molecule expression in a range of different tissues and mouse strains, including non-obese diabetic (NOD) mice. In addition, we examined whether the level of expression of MHC class I molecules influences autoantigen-driven CD8 T cell transmigration. Using endothelial cell lines that expressed 'high' (NOD mouse), medium (NOD x C3H/HeJ F(1) generation mice) and no (C3H/HeJ) H-2K(d), we demonstrated in vitro that MHC levels have a profound effect on the activation, adhesion and transmigration of pathogenic, islet autoreactive CD8 T cells. The expression level of MHC class I molecules on endothelial tissues has a direct impact upon the efficiency of migration of autoreactive T cells. The immune phenotype of microvascular endothelium in NOD mice may be an additional contributory factor in disease predisposition or development, and similar phenotypes should be sought in human type 1 diabetes.

Proinsulin peptide immunotherapy in type 1 diabetes: report of a first-in-man Phase I safety study.

Immunotherapeutic strategies under consideration for type 1 diabetes include modification of the autoimmune response through antigen-specific routes. Administration of short peptides representing T cell epitopes targeted by patients with the disease represents one approach. This study evaluated safety and mechanistic outcomes during first-in-man intradermal administration of a human leucocyte antigen-DR4 (HLA-DR4)-restricted peptide epitope of proinsulin (C19-A3). This randomized, open-label study assessed two major theoretical risks of peptide immunotherapy, namely induction of allergic hypersensitivity and exacerbation of the proinflammatory autoimmune response, using clinical assessment and mechanistic assays in vitro. Patients with long-standing type 1 diabetes and HLA-DRB1*0401 genotype received 30 microg (n = 18) or 300 microg (n = 18) of peptide in three equal doses at 0, 1 and 2 months or no intervention (n = 12). Proinsulin peptide immunotherapy in the dosing regimen used is well tolerated and free from risk of systemic hypersensitivity and induction/reactivation of proinsulin-specific, proinflammatory T cells. Peptide-specific T cells secreting the immune suppressive cytokine interleukin (IL)-10 were observed at month 3 in four of 18 patients in the low-dose group (versus one of 12 in the control group; P = not significant). Mean IL-10 response to peptide in the low-dose group increased between 0 and 3 months (P = 0.05 after stimulation with 5 microM peptide in vitro) and then declined to baseline levels between 3 and 6 months (P = 0.01 at 10 microM peptide in vitro). These studies pave the way for future investigations in new-onset patients designed to examine whether proinsulin peptide immunotherapy has beneficial effects on markers of T cell autoimmunity and preservation of beta cell mass.

Humoral and cellular immune responses to myelin protein peptides in chronic inflammatory demyelinating polyradiculoneuropathy.

OBJECTIVES: Evidence that chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease was sought, by studying cellular and humoral immune responses to peripheral nerve myelin proteins. METHODS: 40 CIDP, 36 healthy control subjects (HC) and subjects with non-immune mediated neuropathies (other neuropathies, ON) for antibodies were studied by ELISA and cellular responses by cytokine ELISPOT (INF gamma, IL10) and ELISA (IL17) to synthetic peptides representing P0, P2 and PMP22. RESULTS: Antibodies to P0, P2 or PMP22 peptides were detected in only a minority of CIDP, both not treated (nT-CIDP) and treated (T-CIDP). IgG antibodies to P2(80-105) were significantly more frequent in CIDP than in HC (4/30 vs 0/32; p<0.05) but the difference from ON (1/25) was not significant. In ELISPOT assays, IFN gamma was detected at a low frequency in CIDP and did not differ from HC or ON. In contrast, IL10 responses against P2(1-85) were more frequent in nT and T-CIDP (7/24 and 3/16) than HC (0/36; p<0.001 and p<0.05, respectively). The production of IL17 in cell-culture supernatants was not increased. CONCLUSIONS: Antibodies to non-conformational antigenic epitopes of myelin proteins rarely occur in CIDP. None of the myelin protein peptides elicited IFN gamma responses, but P2 elicited IL10 responses significantly more often in CIDP patients than in controls. This reactivity may be part of an antigen-specific Th2 type pathogenetic or regulatory mechanism or represent a transitory epiphenomenon due to nerve damage. In our study, P2 was the protein antigen most likely to be involved in the aberrant immune responses in CIDP.

Conjugation of a peptide autoantigen to gold nanoparticles for intradermally administered antigen specific immunotherapy.

Antigen specific immunotherapy aims to tolerise patients to specific autoantigens that are responsible for the pathology of an autoimmune disease. Immune tolerance is generated in conditions where the immune response is suppressed and thus gold nanoparticles (AuNPs) are an attractive drug delivery platform due to their anti-inflammatory effects and their potential to facilitate temporal and spatial delivery of a peptide autoantigen in conjunction with pro-tolerogenic elements. In this study we have covalently attached an autoantigen, currently under clinical evaluation for the treatment of type 1 diabetes (PIC19-A3 peptide), to AuNPs to create nanoscale (<5 nm), negatively charged (-40 to -60 mV) AuNP-peptide complexes for immunotherapy. We also employ a clinically approved microneedle delivery system, MicronJet600, to facilitate minimally-invasive intradermal delivery of the nanoparticle constructs to target skin-resident antigen presenting cells, which are known to be apposite target cells for immunotherapy. The AuNP-peptide complexes remain physically stable upon extrusion through microneedles and when delivered into ex vivo human skin they are able to diffuse rapidly and widely throughout the dermis (their site of deposition) and, perhaps more surprisingly, the overlying epidermal layer. Intracellular uptake was extensive, with Langerhans cells proving to be the most efficient cells at internalising the AuNP-peptide complex (94% of the local population within the treated region of skin). In vitro studies showed that uptake of the AuNP-peptide complexes by dendritic cells reduced the capacity of these cells to activate naïve T cells. This indicator of biological functionality encourages further development of the AuNP-peptide formulation, which is now being evaluated in clinical trials.