Limitations of IL-2 and Rapamycin in Immunotherapy of Type 1 Diabetes

Administration of low-dose interleukin-2 (IL-2) alone or combined with rapamycin (RAPA) prevents hyperglycemia in NOD mice. Also, low-dose IL-2 cures recent-onset type 1 diabetes (T1D) in NOD mice, partially by boosting pancreatic regulatory T cells (T_reg cells). These approaches are currently being evaluated in humans. Our objective was to study the effect of higher IL-2 doses (250,000–500,000 IU daily) as well as low-dose IL-2 (25,000 IU daily) and RAPA (1 mg/kg daily) (RAPA/IL-2) combination. We show that, despite further boosting of T_reg cells, high doses of IL-2 rapidly precipitated T1D in prediabetic female and male mice and increased myeloid cells in the pancreas. Also, we observed that RAPA counteracted IL-2 effects on T_reg cells, failed to control IL-2–boosted NK cells, and broke IL-2–induced tolerance in a reversible way. Notably, the RAPA/IL-2 combination failure to cure T1D was associated with an unexpected deleterious effect on glucose homeostasis at multiple levels, including β-cell division, glucose tolerance, and liver glucose metabolism. Our data help to understand the therapeutic limitations of IL-2 alone or RAPA/IL-2 combination and could lead to the design of improved therapies for T1D.In type 1 diabetes (T1D), the immune system destroys the pancreatic β-cells (1). At clinical onset, ∼30% of β-cells are still able to produce insulin (2), thus stopping autoimmune destruction, which at this stage is a promising approach (3). Along the same lines, there is a growing list of phase I/II clinical trials based on immunomodulation that are currently being conducted in T1D patients (4).NOD mice, which develop spontaneous T1D, represent an accepted model for testing new therapies (5), the gold standard being that treatments that cure overt hyperglycemia in these mice may be most appropriate for translation into the clinic, as was the case for anti-CD3 antibodies (Abs) (6), which have been tested in patients with promising results (7). In addition, results from our own group showing that low-dose interleukin-2 (IL-2) can prevent (8) and revert disease in NOD mice (9) have led to the translation of this strategy into clinical trials in T1D patients (clinical trial reg. no. {"type":"clinical-trial","attrs":{"text":"NCT01353833","term_id":"NCT01353833"}}NCT01353833, clinicaltrials.gov).We have shown that in NOD mice, administration of low-dose IL-2 for 5 days induced the remission of new-onset T1D by specifically boosting regulatory T cells (T_reg cells) in the pancreas without activating pathogenic effector T cells (T_eff cells). However, remission was obtained in only 60% of treated mice, and half of them became diabetic again during the following months (9). Consequently, improving IL-2 therapy by optimizing dosing or combining IL-2 with other immunomodulatory drugs, such as rapamycin (RAPA), could be of great importance for the goal of translating this therapy to humans.RAPA has been used in clinical transplantation for many years (10), and it has been safely administered to T1D patients during islet transplantation (11,12). In mice, RAPA monotherapy can prevent T1D development (13); however, it is unable to induce disease reversal (14). Moreover, RAPA and IL-2 were found to be synergistic for the prevention of diabetes in NOD mice (13). Consequently, we decided to test whether RAPA could synergize with short-term IL-2 therapy to reverse T1D and reinforce the development of long-term tolerance.In this work, we have further studied the mechanisms of action of IL-2 and RAPA alone or in combination in the NOD model of T1D.     

Protection Against Type 1 Diabetes Upon Coxsackievirus B4 Infection and iNKT-Cell Stimulation: Role of Suppressive Macrophages

Invariant natural killer T (iNKT) cells belong to the innate immune system and exercise a dual role as potent regulators of autoimmunity and participate in responses against different pathogens. They have been shown to prevent type 1 diabetes development and to promote antiviral responses. Many studies in the implication of environmental factors on the etiology of type 1 diabetes have suggested a link between enteroviral infections and the development of this disease. This study of the pancreatropic enterovirus Coxsackievirus B4 (CVB4) shows that although infection accelerated type 1 diabetes development in a subset of proinsulin 2–deficient NOD mice, the activation of iNKT cells by a specific agonist, α-galactosylceramide, at the time of infection inhibited the disease. Diabetes development was associated with the infiltration of pancreatic islets by inflammatory macrophages, producing high levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α and activation of anti-islet T cells. On the contrary, macrophages infiltrating the islets after CVB4 infection and iNKT-cell stimulation expressed a number of suppressive enzymes, among which indoleamine 2,3-dioxygenase was sufficient to inhibit anti-islet T-cell response and to prevent diabetes. This study highlights the critical interaction between virus and the immune system in the acceleration or prevention of type 1 diabetes.Type 1 diabetes is characterized by the destruction of pancreatic islet β-cells by autoreactive CD4 and CD8 T cells, leading to low insulin production and incapacity to regulate blood glucose levels (1). Despite numerous studies, the etiology of type 1 diabetes remains elusive. Besides genetics (2–4), environmental factors such as viral infections have been suggested as triggers of type 1 diabetes (5–7). Most striking of these infections are the type B Coxsackieviruses belonging to the enterovirus genus whose genome and anti-Coxsackievirus antibodies were detected more frequently in the blood of recently diagnosed patients compared with healthy controls (8,9). Besides, enteroviral RNA or enteroviral particles were directly detected in the pancreas of type 1 diabetic patients, whereas they were undetectable in the pancreas of healthy donors (9,10). In a mouse model of type 1 diabetes, Serreze et al. (11) showed that diabetes can develop rapidly after Coxsackievirus B4 (CVB4) infection if mice had an advanced age and sufficient insulitis. Others have reported that inefficient islet β-cell response, viral dose, and replication rate as well as a lack of islet neogenesis could also promote accelerated diabetes development after CVB4 infection (12–14).Natural killer T (NKT) cells are CD1d-restricted, nonconventional T cells recognizing self and exogenous glycolipids. Most NKT cells express an invariant T-cell receptor α chain, Vα14-Jα18 (Vα14) in mice and Vα24-Jα18 in humans, and are named invariant NKT (iNKT) cells. They can promptly secrete copious amounts of interferon-γ (IFN-γ) and interleukin (IL)-4 and provide maturation signals to dendritic cells (DCs) and lymphocytes, thereby contributing to both innate and acquired immunity (15,16). iNKT cells are potent regulatory cells that can inhibit autoimmunity and promote immune responses against pathogens (1,17). Diabetes can be prevented in NOD mice by increasing iNKT cell numbers and by iNKT-cell stimulation with exogenous ligands such as α-galactosylceramide (αGalCer) (15,18,19). NOD mice protected from diabetes by iNKT cells have weak T helper 1 anti-islet β-cell responses (20). Indeed, iNKT cells can impair the differentiation of anti-islet CD4 and CD8 T cells, which become hyporesponsive or anergic (21). Contrary to their suppressive role in type 1 diabetes, iNKT cells can enhance immune responses to pathogens such as parasites, bacteria, and viruses (22,23).Our previous studies conducted in a murine model of type 1 diabetes with lymphocytic choriomeningitis virus infection revealed that iNKT cells could promote systemic antiviral CD8 T-cell responses while inhibiting deleterious anti-islet T-cell responses, thereby preventing type 1 diabetes (24,25). In the present study, we investigated the role of iNKT cells after CVB4 infection, revealing that diabetes development following CVB4 infection is associated with the infiltration of inflammatory macrophages into the pancreatic islets with subsequent activation of anti-islet T cells. However, the activation of iNKT cells during CVB4 infection results in the infiltration of suppressive macrophages into pancreatic islets. Indoleamine 2,3-dioxygenase (IDO) expressed by these macrophages was critical for the inhibition of diabetes development.     

Anaemia during pregnancy: impact on birth outcome and infant haemoglobin level during the first 18 months of life

To determine the effect of maternal anaemia on pregnancy outcome and describe its impact on infant haemoglobin level in the first 18 months of life, we conducted a prospective study of 617 pregnant women and their children in Benin. Prevalence of maternal anaemia at delivery was 39.5%, and 61.1% of newborns were anaemic at birth. Maternal anaemia was not associated with low birth weight [OR = 1.2 (0.6-2.2)] or preterm birth [OR = 1.3 (0.7-2.4)], whereas the newborn's anaemia was related to maternal anaemia [OR = 1.8 (1.2-2.5)]. There was no association between an infant's haemoglobin level until 18 months and maternal anaemia. However, malaria attacks during follow-up, male gender and sickle cell trait were all associated with a lower infant haemoglobin level until 18 months, whereas good infant feeding practices and a polygamous family were positively associated with a higher haemoglobin level during the first 18 months of life.     

Chronic meningococcemia cutaneous lesions involve meningococcal perivascular invasion through the remodeling of endothelial barriers

Chronic meningococcemia is a form of sepsis with frequent polymorphous skin lesions. Both in vivo and in vitro data suggest that, in these lesions, meningococci gain access from the capillary lumen to the peripheral extravascular compartment, in the absence of vascular dislocation, through a paraendothelial route.     

Association between Staphylococcus aureus alone or combined with Pseudomonas aeruginosa and the clinical condition of patients with cystic fibrosis

BackgroundThe prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients has increased and MRSA seems to be associated with a poorer prognosis. The aim of this study was to assess the prevalence and clinical consequences of MRSA and methicillin-susceptible Staphylococcus aureus (MSSA), associated or not associated with Pseudomonas aeruginosa (PA).MethodsIn a retrospective study on 419 sputum producer patients (293 adults and 126 children > 7 years of age), we recorded patient characteristics, lung function, nutritional status, IV antibiotics and hospitalisations, the presence of SA and/or PA and FEV1 decline over 2 years.ResultsSA was found in 72% of the patients: MSSA in 68.2% of children and 48.8% of adults; MRSA in 17.5% of children and 17.8% of adults. Sixty percent of MRSA patients and 60.4% of MSSA patients also harboured PA. The rate of deterioration of clinical status of the various groups, as assessed from respiratory function, IV antibiotic courses and hospitalisations, increased in the order: no SA/no PA, MSSA alone, MRSA alone, MSSA/PA, MRSA/PA, and PA alone. Nutritional status did not differ between groups. Results were roughly similar for children and adults. The yearly FEV1 decline was significantly higher only for MRSA/PA patients (p = 0.03) compared to no SA/no PA patients.ConclusionClinical condition of CF patients with MSSA only or MRSA only appeared similar, whereas MRSA/PA patients had more severe respiratory function than MSSA/PA patients. In CF patients, MRSA might be more deleterious than MSSA only when associated with PA.     

A case–control study of fractures in men with idiopathic osteoporosis: Fractures are associated with older age and low cortical bone density

ObjectivesTo determine biochemical, radiological and micro-architectural bone factors related to fragility fractures in idiopathic male osteoporosis (IMO) patients. IMO is a rare disorder characterized by low areal bone mineral density (aBMD) (Z-score < ? 2) occurring in men after excluding secondary causes of low BMD.MethodsWe conducted a case–control study in 31 patients with fragility fracture (IMO F +) that had occurred after the age of 40 years and 37 without fracture (IMO F–). We first compared IMO group to 40 age-matched disease-free men. We measured aBMD and bone micro-architectural indices at distal radius and tibia sites with a HR-pQCT scan (XtremeCT) using standard and extended cortical analysis. Urine and blood samples were collected in order to determine the levels of bone-turnover markers and the potential determinant of bone fragility. Models of analysis of covariance, including age, height and weight as adjustment factors, were used to compare the groups.ResultsCompared to their controls, IMO patients showed marked disturbance of their micro‐architectural parameters at tibia and radius affecting both trabecular and cortical parameters. IMO F + subjects were significantly older than IMO F ? subjects (58 ± 8 vs. 53 ± 9 yrs, p = 0.01). BMD Z-score at the total-hip was significantly lower in IMO F + (? 1.3 ± 0.5 vs. ? 0.9 ± 0.8 g/cm², p = 0.01). After adjustment, trabecular micro‐architectural parameters, biochemical markers and hormonal parameters were not different in the 2 groups. At distal tibia, cortical v-BMD was significantly lower in IMO F + patients (799 ± 73 vs. 858 ± 60 mg/cm³, p = 0.03), while cortical thickness was not different.ConclusionOur results show that patients with IMO display a marked disturbance of trabecular and cortical bone micro-architecture, and that age and low cortical density are determinants of the fracture occurrence.