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Despite early clinical successes, the mechanisms of action of low-dose interleukin-2 (LD-IL-2) immunotherapy remain only partly understood. Here, we examined the effects of interval administration of low-dose recombinant IL-2 (iLD-IL-2) using high-resolution, single-cell multiomics and flow cytometry. We confirmed that iLD-IL-2 selectively expands thymic-derived FOXP3+HELIOS+Tregs and CD56brNK cells, and showed that treatment reduced the frequency of IL-21-producing CD4+T cells and of two subsets of innate-like CD8+T cells, mucosal-associated invariant T cells and Vγ9Vδ2T cells. The cellular changes induced by LD-IL-2 were associated with an anti-inflammatory gene expression signature, which remains detectable in all T and NK cell subsets analysed one month after treatment. The anti-inflammatory nature of this gene expression signature was supported by the observation that the same genes were also modulated in COVID-19 patients, but in the opposite direction. These findings warrant continued investigations of the potential clinical benefits of iLD-IL-2 in immunotherapy and further understanding of the development of long-term sequelae in convalescent COVID-19 patients.

BACKGROUND. Type 1 diabetes (T1D) results from loss of immune regulation, leading to the development of autoimmunity to pancreatic β cells, involving autoreactive T effector cells (Teffs). Tregs, which prevent autoimmunity, require IL-2 for maintenance of immunosuppressive functions. Using a response-adaptive design, we aimed to determine the optimal regimen of aldesleukin (recombinant human IL-2) to physiologically enhance Tregs while limiting expansion of Teffs. METHODS. DILfrequency is a nonrandomized, open-label, response-adaptive study of participants, aged 18–70 years, with T1D. The initial learning phase allocated 12 participants to 6 different predefined regimens. Then, 3 cohorts of 8 participants were sequentially allocated dose frequencies, based on repeated interim analyses of all accumulated trial data. The coprimary endpoints were percentage change in Tregs and Teffs and CD25 (α subunit of the IL-2 receptor) expression by Tregs, from baseline to steady state. RESULTS. Thirty-eight participants were enrolled, with thirty-six completing treatment. The optimal regimen to maintain a steady-state increase in Tregs of 30% and CD25 expression of 25% without Teff expansion is 0.26 × 106 IU/m2 (95% CI –0.007 to 0.485) every 3 days. Tregs and CD25 were dose-frequency responsive, Teffs were not. The commonest adverse event was injection site reaction (464 of 694 events). CONCLUSIONS. Using a response-adaptive design, aldesleukin treatment can be optimized. Our methodology can generally be employed to immediately access proof of mechanism, thereby leading to more efficient and safe drug development. TRIAL REGISTRATION. International Standard Randomised Controlled Trial Number Register, ISRCTN40319192; ClinicalTrials.gov, {"type":"clinical-trial","attrs":{"text":"NCT02265809","term_id":"NCT02265809"}}NCT02265809. FUNDING. Sir Jules Thorn Trust, the Swiss National Science Foundation, Wellcome, JDRF, and NIHR Cambridge Biomedical Research Centre.

SummaryBackgroundType 1 diabetes (T1D) results from loss of immune regulation leading to the development of autoimmunity to pancreatic beta-cells, involving autoreactive T effector cells (Teffs). Regulatory T cells (Tregs), that prevent autoimmunity, require Interleukin-2 (IL-2) for maintenance of immunosuppressive functions and, alterations in the IL-2 pathway predispose to T1D. Using an adaptive trial design we aimed to determine the optimal regimen of aldesleukin (recombinant human IL-2) to physiologically enhance Tregs while limiting expansion of autoreactive Teffs.MethodsDILfrequency is a single-center, non-randomised, open-label, response-adaptive study of participants aged 18 to 70 years with T1D. The initial learning phase allocated 12 participants to six different predefined dose-frequency regimens. Then, three cohorts of 8 participants were sequentially allocated dose-frequencies, based on repeated interim analyses of all accumulated trial data. The co-primary endpoints were percentage change in Tregs, Teffs and, CD25 (α subunit of the IL-2 receptor) expression by Tregs, from baseline to steady state. Trial registration ISRCTN40319192 and ClinicalTrials.gov (NCT02265809).Findings115 participants were assessed between November 17th 2014 and May 22nd 2016, 38 participants were enrolled with 36 completing treatment. The optimal regimen to maintain a steady state increase in Tregs of 30% and CD25 expression of 25% without Teff expansion is 0.26 × 106 IU/m2 (95% CI (−0.007 to 0.485)) every 3 days (1.3 to 4.4). Tregs and CD25 were dose-frequency responsive, while Teffs were not. The commonest adverse event was injection site reaction (464/694 events), with a single participant developing transient eosinophilia at the highest dose (0.47 × 106 IU/m2).InterpretationThis response-adaptive trial defined a well-tolerated aldesleukin regimen that specifically induces Treg expansion that can now be trialled to treat T1D.FundingSir Jules Thorn Trust, Wellcome, JDRF, SNSF, NIHR

Background: The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen. Methods: Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel. Results: Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4+ T cell (Treg), effector T cell (Teff) CD4+ and CD8+ subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later. NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69+ and Ki-67+ effector memory Teffs were followed by the emergence of memory CD8+ Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues. Conclusions: The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection.

Immune-deficient mice, reconstituted with human stem cells, have been used to analyze human immune responses in vivo. Although they have been used to study immune responses to xenografts, allografts, and pathogens, there have not been models of autoimmune disease in which the mechanisms of the pathologic process can be analyzed. We have found that reconstituted “humanized” mice treated with anti–CTLA-4 Ab (ipilimumab) develop autoimmune disease characterized by hepatitis, adrenalitis, sialitis, anti-nuclear Abs, and weight loss. Induction of autoimmunity involved activation of T cells and cytokine production, and increased infiltration of APCs. When anti–CTLA-4 mAb–treated mice were cotreated with anti-CD3 mAb (teplizumab), hepatitis and anti-nuclear Abs were no longer seen and weight loss did not occur. The anti-CD3 blocked proliferation and activation of T cells, release of IFN-γ and TNF, macrophage infiltration, and release of IP-10 that was induced with anti–CTLA-4 mAb. We also found increased levels of T regulatory cells (CD25+CD127−) in the spleen and mesenteric lymph nodes in the mice treated with both Abs and greater constitutive phosphorylation of STAT5 in T regulatory cells in spleen cells compared with mice treated with anti–CTLA-4 mAb alone. We describe a model of human autoimmune disease in vivo. Humanized mice may be useful for understanding the mechanisms of biologics that are used in patients. Hepatitis, lymphadenopathy, and other inflammatory sequelae are adverse effects of ipilimumab treatment in humans, and this study may provide insights into this pathogenesis and the effects of immunologics on autoimmunity.

We report a novel case of insulin autoimmune syndrome (IAS) presenting with hypoglycemia due to production of a monoclonal anti-insulin antibody in a patient subsequently found to have multiple myeloma (MM).The aim of the study was to describe the 5-yr clinical course of a patient with IAS and MM and to characterize the origin and function of the pathogenic antibody.We conducted a longitudinal case history with laboratory investigations to characterize the anti-insulin antibody subtype, specificity, affinity, and origin.The patient presented with IAS, which worsened during treatment of hepatitis C. The patient was then discovered to have a monoclonal gammopathy that progressed to MM. Treatment of the MM induced remission of the neoplasia and IAS, which then followed a synchronized course of progression and response to therapy. An anti-insulin IgG(3)-λ that bound specifically but with low affinity to the insulin B chain (amino acids 9-30) and that was distinct from the primary MM IgG(3)-κ clone was recovered from the patient and cloned. The antibody bound insulin and showed mutations of normal affinity maturation.We describe a case of MM heralded by IAS, where full characterization of the pathogenic antibody revealed that the monoclonal anti-insulin antibody had originated from a self-reactive clone.

The adaptive immune system utilizes multiple mechanisms linked to innate immune cell functions to respond appropriately to pathogens and commensals. Here we discover further aspects of this connectivity by demonstrating that naïve T cells as they emerge from the thymus (recent thymic emigrants, RTEs) express complement receptors (CR1 and CR2), the bacterial pathogen recognition receptor TLR1 and an enzyme that deactivates bacterial lipopolysaccharide (AOAH) and following activation secrete the anti-microbial cytokine IL-8. CR2+ naïve T cells also express a selection of genes associated with tissue migration, consistent with the hypothesis that following emigration from the thymus RTEs seed peripheral compartments where some pursue their anti-microbial potential by becoming IL-8-producing CR2+ memory cells while others undergo homeostatic expansion. CR2+ naïve and memory cells are abundant in children but decrease with age, coinciding with the involution of the thymus. The ability of CR2, which is also a receptor for Epstein-Barr Virus (EBV), to identify recent thymic emigrants will facilitate assessment of thymic function during aging and aid investigations of multiple clinical areas including the occurrence of T cell lymphomas caused by EBV.

Preclinical testing of human therapeutic monoclonal antibodies has been limited in murine models due to species differences in pharmacokinetics and biologic responses. To overcome these constraints we developed a murine skin transplant model in humanized mice and used it to test human monoclonal antibody therapy. Neonatal NOD/SCID/IL2Rγc(null) mice (NSG) were reconstituted with human CD34(+) hematopoietic stem cells (hNSG). When adult, these mice rejected MHC mismatched murine C57BL/6J skin grafts. Rejection required adequate reconstitution with human cells. There was diffuse infiltration of the epidermis and dermis with hCD8 and hCD4 cells in rejected grafts by immunohistochemistry. Studies with B6/MHC class I and II knockout mice donors indicated that neither is required for rejection. Graft rejection was associated with the development of effector and central memory T cells and an increase in serum immunoglobulins. We also tested the effects of teplizumab (anti-CD3 mAb) and found it could delay skin graft rejection, whereas ipilimumab (anti-CTLA-4 [cytotoxic T-lymphocyte antigen-4] mAb) treatment accelerated rejection. These findings demonstrate that hNSG mice reliably and predictably reject a xenogenic mouse skin graft by a human T cell mediated mechanism. The model can be utilized to investigate the ability of human immunotherapies to enhance or suppress functional human immune responses.

Type 1 diabetes is a common, severe chronic autoimmune disease that is characterized by the progressive and insidious loss of self-tolerance to the insulin-producing pancreatic islet β-cells. This loss of self-tolerance leads to the destruction of β-cells and the development of overt hyperglycaemia at diagnosis. The incidence and prevalence of type 1 diabetes is rapidly increasing worldwide, and this has led to intensive efforts to develop immunotherapies to induce remission of the disease and improve clinical outcomes. Immunotherapy aims to restore self-tolerance, resulting in the downregulation of autoimmune responses to pancreatic self-antigens and arrested ongoing β-cell destruction. When combined with replacement of the lost insulin-producing cells, this may lead to the restoration of euglycaemia. In this review, we discuss the current knowledge of the immunopathogenesis of type 1 diabetes and how this information has been translated into clinical trials. We also discuss next-generation combination immunotherapies that may be administered as adjuvant therapy at time of diagnosis.

Patients with type 1 diabetes have an increased prevalence of coeliac disease as compared with the general population due to common genotypes. Recent evidence has suggested that deregulation of gastrointestinal mucosal immunity may be essential to the development of both diseases. Currently, strong evidence supports the serological screening of paediatric patients with type 1 diabetes for coeliac disease. A key clinical question in the management of type 1 diabetes is whether adult patients should be routinely screened for coeliac disease. To investigate the use of coeliac screening in endocrine practice we retrospectively reviewed the records of 4,138 patients attending our diabetes centre over a four-year period and identified 572 patients with type 1 diabetes. We found that approximately one out of five patients with type 1 diabetes had been serologically screened for coeliac disease. The prevalence of coeliac disease at 1.69% in this adult cohort was lower than expected. This demonstrates that a significant proportion of adult patients with type 1 diabetes had been serologically screened for coeliac disease as part of routine care despite there being no clear indication to test. Br J Diabetes Vasc Dis 2009;9:288–291

The prevalence of coeliac disease in patients with type 1 diabetes is significantly increased when compared to the general population. Ancompared to the general population. An explanation of the association between the development of both diseases may be explained by the inheritance of common major histocompatibility complex immunogenotypes that influence the presentation of auto antigens to CD4+ T-Cells. The subsequent loss of self tolerance results in destruction of the small bowel villi and pancreatic β-cells in coeliac and type 1 diabetes respectively. The diagnosis of coeliac disease in type 1 diabetic patients occurs commonly as a result of screening of individuals with subclinical coeliac disease. Recent studies have demonstrated the clinical benefit of treating subclinical coeliac disease in children with improvement in growth parameters, resolution of anaemia and fewer hypoglycaemic episodes. There is no current clinical evidence supporting routine screening of adult type 1 diabetic patients for coeliac disease. After the diagnosis of coeliac disease, type 1 diabetic patients should be commenced on a gluten-free diet with care co-ordinated between a dietician, gastroenterologist anddiabetologist.

Background A barrier to the successful development of new disease treatments is the timely recruitment of participants to experimental medicine studies that are primarily designed to investigate biological mechanisms rather than evaluate clinical efficacy. The aim of this study was to analyse the performance of three recruitment sources and the effect of publicity events during the Adaptive study of IL-2 dose on regulatory T cells in type 1 diabetes (DILT1D). Methods The final study outcome, demography, disease duration, residence and the effect of publicity events on the performance of three recruitment sources (clinics, type 1 diabetes (T1D) disease register and the internet) were analysed from a bespoke DILT1D recruitment database. For the internet source, the origin of website hits in relation to publicity events was also evaluated. Results A total of 735 potentially eligible participants were approached to identify the final 45 DILT1D participants. A total of 477 (64%) were identified via the disease register, but only 59 (12%) responded to contact. A total of 317 individuals registered with the DILT1D study team. Self-referral via the study website generated 170 (54%) registered individuals and was the most popular and successful source, with 88 (28%) sourced from diabetes clinics and 59 (19%) from the disease register. Of those with known T1D duration (N = 272), the internet and clinics sources identified a larger number (57, 21%) of newly diagnosed T1D (

DIABETES TECHNOLOGY & THERAPEUTICS Volume 16, Supplement 1, 2014 a Mary Ann Liebert, Inc. DOI: 10.1089/dia.2014.1510 ORIGINAL ARTICLE Immune Intervention for Type 1 Diabetes, 2012–2013 Jay S. Skyler Introduction Results T Teplizumab (14-day full dose) reduced the loss of C-peptide mean area under curve (AUC; a prespecified secondary end- point) at 2 years versus placebo. In analyses of subsets at entry, U.S. residents, patients with C-peptide mean AUC > 0.2 nmol/L, those randomized < 6 weeks after diagnosis, HbA1c < 7.5% (58 mmol/mol), insulin use < 0.4 U/kg/day, and ages 8–17, each had greater teplizumab-associated C-peptide preservation than their counterparts. Exogenous insulin needs tended to be re- duced versus placebo. Antidrug antibodies developed in some patients without apparent change in drug efficacy. No new safety or tolerability issues were observed during year 2. his chapter of the ATTD 2013 Yearbook reviews the key articles that have appeared between July 2012 and August 2013 in the area of immune intervention in type 1 diabetes. Also included are two studies dealing with beta-cell regen- eration or replacement. The first three studies discussed deal with anti-CD3 monoclonal antibody therapy. Teplizumab preserves C-peptide in recent-onset type 1 diabetes: 2-year results from the randomized, placebo-controlled Protege trial Hagopian W 1 , Ferry RJ Jr 2 , Sherry N 3 , Carlin D 4 , Bonvini E 4 , Johnson S 4 , Stein KE 4 , Koenig S 4 , Daifotis AG 4 , Herold KC 5 , Ludvigsson J 6 ; for the Prote´ge´ Trial Investigators Pacific Northwest Diabetes Research Institute, Seattle, WA; 2 Divi- sion of Pediatric Endocrinology and Metabolism, Le Bonheur Chil- dren’s Hospital and University of Tennessee Health Science Center, Memphis, TN; 3 Massachusetts General Hospital, Boston, MA; MacroGenics, Rockville, MD; 5 Departments of Immunobiology and Internal Medicine, Yale University, New Haven, CT; and 6 Division of Pediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linko¨ping University, Linko¨ping, Sweden Conclusion Anti-CD3 therapy reduced C-peptide loss and thus pre- served b-cell function for 2 years. Diabetes 2013 Jun 25: [Epub ahead of print]; DOI: 10/2337/db13-0236 Background Two years ago we discussed the 1-year results of the Prote´ge´ phase 3 study using teplizumab. The primary outcome measure—a composite of the percentage of patients with in- sulin use of < 0.5 U/kg per day and HbA1c of < 6.5% at 1 year— was not met. However, exploratory analyses suggested that teplizumab could help preserve b-cell function—as measured by C-peptide—at 1 year, particularly in subgroups such as children. This report describes the 2-year results from this study. Methods Of the 516 subjects randomized, 462 completed 2 years of follow-up. Treatment was given both at study entry and 6 months later. Comment Previous reports have shown that a short course of hu- manized anti-CD3 monoclonal antibody—either with teplizumab or otelixizumab—preserved b-cell function as measured by C-peptide. The Prote´ge´ study selected a different primary outcome measure—a composite of the percentage of patients with insulin use of < 0.5 U/kg/ day plus HbA1c of < 6.5% at 1 year. That outcome was not met, and thus many have labeled the Prote´ge´ study a failure. Yet, in the original report, teplizumab was found to preserve b-cell function at 1 year. The current article demonstrates that this effect was maintained at 2 years. As noted in our earlier discussion of the 1-year results, there was no prior basis for the outcome measure se- lected. Moreover, taking two continuous variables (in- sulin use and HbA1c) and converting them to a single combined dichotomous variable reduces the statistical power of assessment of continuous variables. The C- peptide results, both at 1 year and at 2 years, highlight the problem. Thus, although the original primary outcome was not met, we are still learning from the Prote´ge´ study. Division of Endocrinology, Diabetes, & Metabolism, and Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL. S-85

The development and optimization of immune therapies in patients has been hampered by the lack of preclinical models in which their effects on human immune cells can be studied. As a result, observations that have been made in preclinical studies have suggested mechanisms of drug action in murine models that have not been confirmed in clinical studies. Here, we used a humanized mouse reconstituted with human hematopoietic stem cells to study the mechanism of action of teplizumab, an Fc receptor nonbinding humanized monoclonal antibody to CD3 being tested in clinical trials for the treatment of patients with type 1 diabetes mellitus. In this model, human gut-tropic CCR6(+) T cells exited the circulation and secondary lymph organs and migrated to the small intestine. These cells then produced interleukin-10 (IL-10), a regulatory cytokine, in quantities that could be detected in the peripheral circulation. Blocking T cell migration to the small intestine with natalizumab, which prevents cellular adhesion by inhibiting α(4) integrin binding, abolished the treatment effects of teplizumab. Moreover, IL-10 expression by CD4(+)CD25(high)CCR6(+)FoxP3 cells returning to the peripheral circulation was increased in patients with type 1 diabetes treated with teplizumab. These findings demonstrate that humanized mice may be used to identify novel immunologic mechanisms that occur in patients treated with immunomodulators.

Type 1 diabetes is a common autoimmune disease that affects millions of people worldwide and has an incidence that is increasing at a striking rate, especially in young children. It results from the targeted self-destruction of the insulin-secreting β cells of the pancreas and requires lifelong insulin treatment. The effects of chronic hyperglycemia – the result of insulin deficiency – include secondary endorgan complications. Over the past two decades our increased understanding of the pathogenesis of this disease has led to the development of new immunomodulatory treatments. None have yet received regulatory approval, but this report highlights recent progress in this area.

Type-1A diabetes (T1D) is characterized by a progressive insidious loss of self-tolerance to pancreatic islet beta cells resulting in their destruction and the development of overt hyperglycemia. Immunotherapy aims either to reverse the autoimmune process thereby preventing the development of the disease (immunoprevention) or to intervene at clinical diagnosis of type-1 diabetes and preserve residual b cell function (immunoreversal). Murine models and clinical studies of patients with type-1 diabetes have provided insights into the immunopathogenesis of type-1 diabetes and have led to the development of immunomodulatory therapeutic strategies. Recent clinical trials of anti-CD3 monoclonal antibody (mAbs) and glutamic acid decarboxylase (GAD) peptide have proven successful in attenuating loss of insulin production. Current individual clinical trials are investigating the use of anti-CD3 mAb, GAD, Rituximab, and Abatacept to maintain insulin responses. These trials will lay the groundwork for future studies in which more complete metabolic correction and immunologic tolerance will be restored, possibly with the use of combinations of therapies.

A 40-year-old woman presented with a 10 day history of episodic vagueness, speech disturbance and blurred vision. Episodes typically occurred in the morning after awaking from sleep and resolved with food ingestion. She had no past medical history, did not drink alcohol and was not on any medication. Physical examination was normal with no evidence of endocrinopathy. After 10 h of fasting, she became hypoglycaemic with evidence of neuroglycopenia, which resolved with intravenous dextrose. Biochemical investigations revealed decreased glucose, insulin and C-peptide values with an increased excess insulin-like growth factor II: excess insulin-like growth factor I (IGF-II: IGF-I) ratio. Radiological examinations of the abdomen and pelvis revealed a heterogenous 10.5 cm left renal mass. The patient underwent a radical left nephrectomy. She had complete resolution of hypoglycaemic events. Histology revealed a renal sarcoma, grade 2/3. This is the first report in the literature involving a renal sarcoma causing non-islet cell tumour hypoglycaemia via excess IGF-II secretion.

Refinements in our understanding of the pathogenic mechanisms of Type 1 diabetes from studies of animal models and clinical observation have led to new clinical trials to prevent disease progression and restore the loss of beta-cells that defines the disease. Antigen-specific agents have shown initial promise and non-antigen-specific agents now have improved safety compared with older agents. In addition, preclinical studies with other agents have shown efficacy. Ultimately, a combination of immunologic and cellular therapies may be needed to restore metabolic control. Agents that augment recovery of dysfunctional beta-cells, and other compounds that may be able to induce beta-cell replication, are logical additions once immune tolerance is achieved.

Recent clinical trials have shown that the loss of insulin production that characterizes progressive type 1 diabetes mellitus can be attenuated by treatment with non-FcR binding anti-CD3 monoclonal antibody (mAb). This approach is a first step towards the ultimate goals of treatment: to improve and maintain insulin production. However, additional interventions will be needed because, with time, there is progressive loss of insulin production after treatment with a single course of anti-CD3 mAb. The basis for the long-term loss of insulin production after immune therapy is not known because animal models have not been informative about the mechanisms, and there are not biomarkers of autoimmunity that can be used to monitor the process. Therefore, strategies for clinical testing might involve both beta cell and immunological therapies. Examples of the former include agents such as GLP1 receptor agonists or DPPIV inhibitors which increase beta cell insulin content. Preclinical data suggest that co-administration of antigen with anti-CD3 mAb can induce a tolerogenic response to the antigen that may then be administered to maintain tolerance. In addition, other immunological approaches as well as interventions earlier in the disease process may be successful in maintaining greater beta cell function for extended periods.

Recent clinical trials have shown that the loss of insulin production that characterizes progressive type 1 diabetes mellitus can be attenuated by treatment with non-FcR binding anti-CD3 monoclonal antibody (mAb). This approach is a first step towards the ultimate goals of treatment: to improve and maintain insulin production. However, additional interventions will be needed because, with time, there is progressive loss of insulin production after treatment with a single course of anti-CD3 mAb. The basis for the long-term loss of insulin production after immune therapy is not known because animal models have not been informative about the mechanisms, and there are not biomarkers of autoimmunity that can be used to monitor the process. Therefore, strategies for clinical testing might involve both beta cell and immunological therapies. Examples of the former include agents such as GLP1 receptor agonists or DPPIV inhibitors which increase beta cell insulin content. Preclinical data suggest that co-administration of antigen with anti-CD3 mAb can induce a tolerogenic response to the antigen that may then be administered to maintain tolerance. In addition, other immunological approaches as well as interventions earlier in the disease process may be successful in maintaining greater beta cell function for extended periods.

The DIL-frequency study aims to establish the optimal dose and repeat dosing schedule (interval) to administer ultra-low dose Interlekin-2 to participants with type 1 diabetes in order to target a desired regulatory T cell (Treg) increase and increased CD25 expression on Tregs and a minimal increase of CD4 T effector cells (Teffs). Before the start of the trial, the available doses are chosen within a safe range. The interval is chosen to be within the range 2 to 14 days between doses. The study design has an initial learning phase with pairs of patients assigned to six pre-assigned dose-intervals. There are three further phases of eight patients, participants are given dose-interval combinations that give an expected Treg and CD25 increase closest to the targets of 20% and 25% respectively, provided that there is not an increase in Teffs above a specified level. The primary endpoints are assessed when steady state is achieved. A variety of strategies were considered to select the dose-interval combinations for the next cohort of patients and to identify the recommended dose-interval. The method chosen was to select the dose-interval that would be closest to the target increases of Treg and CD25. The estimated coefficients from the multivariate regression analysis gave equations to predict the estimated increase in Treg and CD25 for any given dose and interval. The targets are substituted into the equations and solved to find the estimated best dose-interval. The results of the simulations are presented.

Continuous glucose monitoring systems provide dynamic measurements of interstitial glucose levels, enabling patients with diabetes mellitus to act preemptively to reduce glycemic variability. The authors of this Viewpoint discuss the advantages of continuous glucose-monitoring systems over self-monitoring of blood glucose, as well factors that limit its availability and success.

The objective of the DILT1D trial is to identify doses of interleukin-2 that achieve targeted increases in the T regulatory cell population in recently diagnosed type 1 diabetes. DILT1D aims to accurately identify a minimally effective dose and a maximal dose in a limited number of patients (40) that may be repeatedly administered in later phase trials. The dose is administered subcutaneously so can be chosen from a continuous range up to a limit chosen on tolerability grounds. The design has an initial learning phase where pairs of patients are assigned to five pre-assigned doses. The next phase is fully sequential with an interim analysis after each patient to determine the choice of dose based on the optimality criterion to minimise the determinant of the covariance of the estimated target doses. The dose-choice algorithm assumes that a specific parametric dose-response model is the true relationship, and so a variety of models are considered at the interim and human judgement involved in the overall decision. Simulation studies found that having two targets and assuming a model with a small number of parameters (≤3) leads to a choice of doses that are not near to the target doses. Fitting models with greater flexibility with more parameters (≥4) results in a choice of doses near to the target doses. Overall the design is efficient and seamlessly combines the initial learning and subsequent confirmatory stages.