Lineage-specific detection of residual disease predicts relapse in patients with chronic myeloid leukemia stopping therapy.

ABSTRACT: Patients with chronic myeloid leukemia who are eligible for treatment-free remission (TFR) may still relapse after tyrosine kinase inhibitor (TKI) cessation. There is a need for accurate predictors of outcome to enable patients with a favorable profile to proceed while avoiding futile attempts. Sensitive detection of residual disease in total leukocytes at treatment cessation is associated with relapse but is not highly discriminatory, likely because it is a composite measure of residual leukemia derived from different cell lineages, whereas only some lineages are relevant for relapse. We prospectively measured BCR::ABL1 DNA as a predictive yes/no binary test in 5 cellular fractions from 48 patients meeting conventional criteria for TKI discontinuation. The median BCR::ABL1 DNA level was higher in granulocytes and T cells, but not in other lineages, in patients who relapsed. Among the 40 patients undergoing their first TFR attempt, we defined 3 groups with differing relapse risk: granulocyte-positive group (100%), granulocyte-negative/T-cell-positive group (67%), and granulocyte-negative /T-cell-negative group (25%). These data show the critical importance of lineage-specific assessment of residual disease in the selection of patients who can attempt to achieve TFR with a high expectation of success and, concurrently, defer patients who have a high probability of relapse.

Biological Sensing of Nitric Oxide in Macrophages and Atherosclerosis Using a Ruthenium-Based Sensor.

Macrophage-derived nitric oxide (NO) plays a critical role in atherosclerosis and presents as a potential biomarker. We assessed the uptake, distribution, and NO detection capacity of an irreversible, ruthenium-based, fluorescent NO sensor (Ru-NO) in macrophages, plasma, and atherosclerotic plaques. In vitro, incubation of Ru-NO with human THP1 monocytes and THP1-PMA macrophages caused robust uptake, detected by Ru-NO fluorescence using mass-cytometry, confocal microscopy, and flow cytometry. THP1-PMA macrophages had higher Ru-NO uptake (+13%, p < 0.05) than THP1 monocytes with increased Ru-NO fluorescence following lipopolysaccharide stimulation (+14%, p < 0.05). In mice, intraperitoneal infusion of Ru-NO found Ru-NO uptake was greater in peritoneal CD11b+F4/80+ macrophages (+61%, p < 0.01) than CD11b+F4/80− monocytes. Infusion of Ru-NO into Apoe−/− mice fed high-cholesterol diet (HCD) revealed Ru-NO fluorescence co-localised with atherosclerotic plaque macrophages. When Ru-NO was added ex vivo to aortic cell suspensions from Apoe−/− mice, macrophage-specific uptake of Ru-NO was demonstrated. Ru-NO was added ex vivo to tail-vein blood samples collected monthly from Apoe−/− mice on HCD or chow. The plasma Ru-NO fluorescence signal was higher in HCD than chow-fed mice after 12 weeks (37.9%, p < 0.05). Finally, Ru-NO was added to plasma from patients (N = 50) following clinically-indicated angiograms. There was lower Ru-NO fluorescence from plasma from patients with myocardial infarction (−30.7%, p < 0.01) than those with stable coronary atherosclerosis. In conclusion, Ru-NO is internalised by macrophages in vitro, ex vivo, and in vivo, can be detected in atherosclerotic plaques, and generates measurable changes in fluorescence in murine and human plasma. Ru-NO displays promising utility as a sensor of atherosclerosis.

Measurement of autophagic flux in humans: an optimized method for blood samples.

Autophagic flux is a critical cellular process that is vastly under-appreciated in terms of its importance to human health. Preclinical studies have demonstrated that reductions in autophagic flux cause cancer and exacerbate chronic diseases, including heart disease and the pathological hallmarks of dementia. Autophagic flux can be increased by targeting nutrition-related biochemical signaling. To date, translation of this knowledge has been hampered because there has been no way to directly measure autophagic flux in humans. In this study we detail a method whereby human macroautophagic/autophagic flux can be directly measured from human blood samples. We show that whole blood samples can be treated with the lysosomal inhibitor chloroquine, and peripheral blood mononuclear cells isolated from these samples could be used to measure autophagic machinery protein LC3B-II. Blocking of autophagic flux in cells while still in whole blood represents an important advance because it preserves genetic, nutritional, and signaling parameters inherent to the individual. We show this method was reproducible and defined LC3B-II as the best protein to measure autophagic flux in these cells. Finally, we show that this method is relevant to assess intra-individual variation induced by an intervention by manipulating nutrition signaling with an ex vivo treatment of whole blood that comprised leucine and insulin. Significantly, this method will enable the identification of factors that alter autophagic flux in humans, and better aid their translation in the clinic. With further research, it could also be used as a novel biomarker for risk of age-related chronic disease.Abbreviations: AMPK: AMP-activated protein kinase; ACTB: actin beta; ATG5: autophagy related 5; BAF: bafilomycin A1; CQ: chloroquine; DMSO: dimethyl sulfoxide; DPBS: Dulbecco's phosphate-buffered saline; EDTA: ethylenediaminetetraacetic acid; KO: knockout; MAP1LC3A/LC3A: microtubule associated protein 1 light chain 3 alpha; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAP1LC3C/LC3C: microtubule associated protein 1 light chain 3 gamma; MTOR: mechanistic target of rapamycin kinase; NBR1: NBR1 autophagy cargo receptor; PBMCs: peripheral blood mononuclear cells; PMNs: polymorphonuclear cells; RPMI: Roswell Park Memorial Institute; SQSTM1: sequestosome 1; TBST: Tris-buffered saline containing 0.1% (v:v) Tween 20; TEM: transmission electron microscopy.

Lineage of measurable residual disease in patients with chronic myeloid leukemia in treatment-free remission.

Approximately half of patients with chronic myeloid leukemia (CML) in sustained deep molecular response who discontinue tyrosine kinase inhibitors (TKIs) remain in treatment-free remission (TFR). Some of these patients have measurable residual disease (MRD) by BCR-ABL1 mRNA testing, and most have detectable BCR-ABL1 DNA by highly sensitive methods. We used fluorescence-activated cell sorting and BCR-ABL1 DNA PCR to investigate the lineage of residual CML cells in TFR. Twenty patients in TFR for >1 year provided blood for sorting into granulocytes, monocytes, B cells, T cells, and NK cells. MRD was identified predominantly in the lymphoid compartment and never in granulocytes. B cells were more often BCR-ABL1 positive than T cells (18 vs 11/20 patients) and at higher levels (median 10-4.9 vs 10-5.7; P = 0.014). In 13 CML patients studied at diagnosis lymphocytes expressing BCR-ABL1 mRNA comprised a small proportion of total leukocytes. These data improve our understanding of TFR biology, since it is now clear that MRD in the blood of TFR patients need not imply the persistence of multipotent CML cells. Lineage-specific assessment of MRD could be explored as a means to improve the prediction of TFR.

mTORC1 plays an important role in osteoblastic regulation of B-lymphopoiesis.

Skeletal osteoblasts are important regulators of B-lymphopoiesis, serving as a rich source of factors such as CXCL12 and IL-7 which are crucial for B-cell development. Recent studies from our laboratory and others have shown that deletion of Rptor, a unique component of the mTORC1 nutrient-sensing complex, early in the osteoblast lineage development results in defective bone development in mice. In this study, we now demonstrate that mTORC1 signalling in pre-osteoblasts is required for normal B-lymphocyte development in mice. Targeted deletion of Rptor in osterix-expressing pre-osteoblasts (Rptorob-/-) leads to a significant reduction in the number of B-cells in the bone marrow, peripheral blood and spleen at 4 and 12 weeks of age. Rptorob-/- mice also exhibit a significant reduction in pre-B and immature B-cells in the BM, indicative of a block in B-cell development from the pro-B to pre-B cell stage. Circulating levels of IL-7 and CXCL12 are also significantly reduced in Rptorob-/- mice. Importantly, whilst Rptor-deficient osteoblasts are unable to support HSC differentiation to B-cells in co-culture, this can be rescued by the addition of exogenous IL-7 and CXCL12. Collectively, these findings demonstrate that mTORC1 plays an important role in extrinsic osteoblastic regulation of B-cell development.

Cell banking for regulatory T cell-based therapy: strategies to overcome the impact of cryopreservation on the Treg viability and phenotype.

The first clinical trials with adoptive Treg therapy have shown safety and potential efficacy. Feasibility of such therapy could be improved if cells are cryopreserved and stored until optimal timing for infusion. Herein, we report the evaluation of two cell-banking strategies for Treg therapy: 1) cryopreservation of CD4+ cells for subsequent Treg isolation/expansion and 2) cryopreservation of ex-vivo expanded Tregs (CD4+CD25hiCD127lo/- cells). First, we checked how cryopreservation affects cell viability and Treg markers expression. Then, we performed Treg isolation/expansion with the final products release testing. We observed substantial decrease in cell number recovery after thawing and overnight culture. This observation might be explained by the high percentage of necrotic and apoptotic cells found just after thawing. Furthermore, we noticed fluctuations in percentage of CD4+CD25hiCD127- and CD4+FoxP3+ cells obtained from cryopreserved CD4+ as well as Treg cells. However, after re-stimulation Tregs expanded well, presented a stable phenotype and fulfilled the release criteria at the end of expansions. Cryopreservation of CD4+ cells for subsequent Treg isolation/expansion and cryopreservation of expanded Tregs with re-stimulation and expansion after thawing, are promising solutions to overcome detrimental effects of cryopreservation. Both of these cell-banking strategies for Treg therapy can be applied when designing new clinical trials.

A novel fluorescent probe reveals starvation controls the commitment of amyloid precursor protein to the lysosome.

Alzheimer's disease is the most important cause of dementia but there is no therapy that has been demonstrated to stop or slow disease progression. Amyloid precursor protein (APP) is the source of amyloid-ß (Aß), which aggregates in Alzheimer's disease to form toxic oligomeric species. The endo-lysosomal system can clear APP and Aß from the cell if these molecular species are trafficked through to the lysosome. Currently, there are no easy methods available for the analysis of lysosomal APP trafficking. We therefore generated a fusion protein (tandem-fluorescent, or tf-APP) that allows detection of changes in APP trafficking using accessible techniques such as flow cytometry. This permits rapid analysis or screening of genes and compounds that alter APP processing in the cell. Using our novel molecular probe, we determined that starvation induces trafficking of APP and APP-carboxy-terminal fragments (APP-CTFs) to the degradative endo-lysosomal network. In line with this finding, suppression of mTOR signalling using AZD8055 also strongly induced trafficking of APP to the endo-lysosomal system. Remarkably, activation of mTOR signalling via RHEB over-expression inhibited the starvation-induced autophagy but did not affect trafficking of tf-APP. These results show tf-APP can be used to determine how APP is trafficked through the lysosomal system of the cell. This molecular probe is therefore useful for determining the molecular mechanism behind the commitment of APP to the degradative pathway or for screening compounds that can induce this effect. This is important as clearance of APP and APP-CTF provides an important potential therapeutic strategy for Alzheimer's disease.

Utilization of leukapheresis and CD4 positive selection in Treg isolation and the ex-vivo expansion for a clinical application in transplantation and autoimmune disorders.

Adoptive transfer of T regulatory cells (Tregs) is of great interest as a novel immunosuppressive therapy in autoimmune disorders and transplantation. Obtaining a sufficient number of stable and functional Tregs generated according to current Good Manufacturing Practice (cGMP) requirements has been a major challenge in introducing Tregs as a clinical therapy. Here, we present a protocol involving leukapheresis and CD4+ cell pre-enrichment prior to Treg sorting, which allows a sufficient number of Tregs for a clinical application to be obtained. With this method there is a decreased requirement for ex- vivo expansion. The protocol was validated in cGMP conditions. Our final Treg product passed all release criteria set for clinical applications. Moreover, during expansion Tregs presented their stable phenotype: percentage of CD4+CD25hiCD127- and CD4+FoxP3+ Tregs was > 95% and > 80%, respectively, and Tregs maintained proper immune suppressive function in vitro. Our results suggest that utilization of leukapheresis and CD4 positive selection during Treg isolation improves the likelihood of obtaining a sufficient number of high quality Treg cells during subsequent ex-vivo expansion and they can be applied clinically.

Co-targeting AR and HSP90 suppresses prostate cancer cell growth and prevents resistance mechanisms.

Persistent androgen receptor (AR) signaling in castration resistant prostate cancer (CRPC) underpins the urgent need for therapeutic strategies that better target this pathway. Combining classes of agents that target different components of AR signaling has the potential to delay resistance and improve patient outcomes. Many oncoproteins, including the AR, rely on the molecular chaperone heat shock protein 90 (Hsp90) for functional maturation and stability. In this study, enhanced anti-proliferative activity of the Hsp90 inhibitors 17-allylamino-demethoxygeldanamycin (17-AAG) and AUY922 in androgen-sensitive and CRPC cells was achieved when the agents were used in combination with AR antagonists bicalutamide or enzalutamide. Moreover, significant caspase-dependent cell death was achieved using sub-optimal agent doses that individually have no effect. Expression profiling demonstrated regulation of a broadened set of AR target genes with combined 17-AAG and bicalutamide compared with the respective single agent treatments. This enhanced inhibition of AR signaling was accompanied by impaired chromatin binding and nuclear localization of the AR. Importantly, expression of the AR variant AR-V7 that is implicated in resistance to AR antagonists was not induced by combination treatment. Likewise, the heat shock response that is typically elicited with therapeutic doses of Hsp90 inhibitors, and is a potential mediator of resistance to these agents, was significantly reduced by combination treatment. In summary, the co-targeting strategy in this study more effectively inhibits AR signaling than targeting AR or HSP90 alone and prevents induction of key resistance mechanisms in prostate cancer cells. These findings merit further evaluation of this therapeutic strategy to prevent CRPC growth.

Preservation of beta cell function after pancreatic islet autotransplantation: University of Chicago experience.

The aim of the study was to assess the rate of insulin independence in patients after total pancreatectomy (TP) and islet autotransplantation in our center. TP followed by islet autotransplantation was performed in 10 patients. Severe unrelenting pain associated with chronic pancreatitis was the major indication for surgery. Islets were isolated using the modified Ricordi method and infused through the portal vein. Exogenous insulin therapy was implemented for at least two months posttransplant to support islet engraftment and was subsequently weaned off, if possible. Median follow-up was 26 months (range, 2 to 60 months). Median islet yield was 158,860 islet equivalents (IEQ) (range, 40,203 to 330,472 IEQ) with an average islet yield of 2,478 IEQ/g (range, 685 to 6,002 IEQ/g) of processed pancreas. One patient developed transient partial portal vein thrombosis, which resolved without sequela. Five (50%) patients are currently off insulin with excellent glucose control and HbA1c below 6. Patients who achieved and maintained insulin independence were transplanted with significantly more islets (median, 202,291 IEQ; range, 145,000 to 330,474 IEQ) than patients who required insulin support (64,348 IEQ; range, 40,203 to 260,476 IEQ; P < 0.05). Patient body mass index and time of chronic pancreatitis prior transplant procedure did not correlate with the outcome. The remaining five patients, who require insulin support, had present C-peptide in blood and experience good glucose control without incidence of severe hypoglycemic episodes. Islet autotransplantation efficiently preserved beta cell function in selected patients with chronic pancreatitis and the outcome correlated with transplanted islet mass.

Accumulation of effector memory CD8+ T cells in nasal polyps.

BACKGROUND: T lymphocytes are prevalent in sinus mucosa and are implicated in chronic rhinosinusitis (CRS) pathogenesis. However, the major T-cell subpopulations, helper (CD4+) and cytotoxic (CD8+), have not been adequately examined in CRS. This study was designed to characterize human sinus mucosa and peripheral blood (PB) CD4+ and CD8+ T cells and their level of differentiation in CRS with nasal polyps (NPs), CRS without NPs, and control patients. METHODS: A prospective study was performed. Percentages of CD4+ and CD8+ T cells and their levels of differentiation were analyzed in sinus mucosa and PB by flow cytometry. Cell populations were defined as naive, central memory, effector memory, and effector T cells using cell surface markers CD45RA, CD62L, and CD27. The influence of coexisting allergy, sinus eosinophilic mucus (EM), and culture results were examined. RESULTS: In all patients, sinus mucosa had a lower percentage of CD4+ and a higher percentage of CD8+ T cells compared with PB. However, CRS with NPs (n = 86) had a significantly higher percentage of mucosal CD8+ T cells compared with CRS without NPs (n = 40) in control (n = 13) patients (p < 0.0001). Effector memory T cells were increased in sinuses compared with PB in all patients; however, the percentage of effector memory CD8+ T cells was greatest in CRS with NP mucosa (p = 0.002). Surprisingly coexisting allergy or culture results did not influence the mucosal T-cell phenotype. CRS with NP patients with sinus EM had a significantly higher percentage of mucosal CD8+ T cells. CONCLUSION: Sinus mucosa in CRS with NPs is characterized by a significant enrichment of CD8+ T cells and a relative deficiency of CD4+ T cells. The majority of NP CD8+ T cells had a terminally differentiated, mature, effector memory phenotype, which raises the question, whether these cells are pathogenic or appear as a consequence of inflammation, independent of the presence of allergy or positive microbial culture.

Regulation of bone morphogenetic protein signalling and cranial osteogenesis by Gpc1 and Gpc3.

From birth, the vault of the skull grows at a prodigious rate, driven by the activity of osteoblastic cells at the fibrous joints (sutures) that separate the bony calvarial plates. One in 2500 children is born with a medical condition known as craniosynostosis because of premature bony fusion of the calvarial plates and a cessation of bone growth at the sutures. Bone morphogenetic proteins (BMPs) are potent growth factors that promote bone formation. Previously, we found that Glypican-1 (GPC1) and Glypican-3 (GPC3) are expressed in cranial sutures and are decreased during premature suture fusion in children. Although glypicans are known to regulate BMP signalling, a mechanistic link between GPC1, GPC3 and BMPs and osteogenesis has not yet been investigated. We now report that human primary suture mesenchymal cells coexpress GPC1 and GPC3 on the cell surface and release them into the media. We show that they inhibit BMP2, BMP4 and BMP7 activities, which both physically interact with BMP2 and that immunoblockade of endogenous GPC1 and GPC3 potentiates BMP2 activity. In contrast, increased levels of GPC1 and GPC3 as a result of overexpression or the addition of recombinant protein, inhibit BMP2 signalling and BMP2-mediated osteogenesis. We demonstrate that BMP signalling in suture mesenchymal cells is mediated by both SMAD-dependent and SMAD-independent pathways and that GPC1 and GPC3 inhibit both pathways. GPC3 inhibition of BMP2 activity is independent of attachment of the glypican on the cell surface and post-translational glycanation, and thus appears to be mediated by the core glypican protein. The discovery that GPC1 and GPC3 regulate BMP2-mediated osteogenesis, and that inhibition of endogenous GPC1 and GPC3 potentiates BMP2 responsiveness of human suture mesenchymal cells, indicates how downregulation of glypican expression could lead to the bony suture fusion that characterizes craniosynostosis.

Cytoskeletal protein Flightless (Flii) is elevated in chronic and acute human wounds and wound fluid: neutralizing its activity in chronic but not acute wound fluid improves cellular proliferation.

Chronic non-healing wounds form a medical need which will expand as the population ages and the obesity epidemic grows. Whilst the complex mechanisms underlying wound repair are not fully understood, remodelling of the actin cytoskeleton plays a critical role. Elevated expression of the actin cytoskeletal protein Flightless I (Flii) is known to impair wound outcomes. To determine if Flii is involved in the impaired healing observed in chronic wounds, its expression in non-healing human wounds from patients with venous leg ulcers was determined and compared to its expression in acute wounds and unwounded skin. Increased expression of Flii was observed in both chronic and acute wounds with wound fluid and plasma also containing secreted Flii protein. Inflammation is a key aspect of wound repair and fluorescence-activated cell sorting (FACS) analysis revealed Flii was located in neutrophils within the blood and that it co-localised with CD16+ neutrophils in chronic wounds. The function of secreted Flii was investigated as both chronic wound fluid and Flii have previously been shown to inhibit fibroblast proliferation. To determine if the inhibitory effect of wound fluid was due in part to the presence of Flii, wound fluids were depleted of Flii using Flii-specific neutralizing antibodies (FnAb). Flii depleted chronic wound fluid no longer inhibited fibroblast proliferation, suggesting that Flii may contribute to the inhibitory effect of chronic wound fluid on fibroblast function. Application of FnAbs to chronic wounds may therefore be a novel approach used to improve the local environment of non-healing wounds and potentially improve healing outcomes.

Characterization of a distinct population of circulating human non-adherent endothelial forming cells and their recruitment via intercellular adhesion molecule-3.

Circulating vascular progenitor cells contribute to the pathological vasculogenesis of cancer whilst on the other hand offer much promise in therapeutic revascularization in post-occlusion intervention in cardiovascular disease. However, their characterization has been hampered by the many variables to produce them as well as their described phenotypic and functional heterogeneity. Herein we have isolated, enriched for and then characterized a human umbilical cord blood derived CD133(+) population of non-adherent endothelial forming cells (naEFCs) which expressed the hematopoietic progenitor cell markers (CD133, CD34, CD117, CD90 and CD38) together with mature endothelial cell markers (VEGFR2, CD144 and CD31). These cells also expressed low levels of CD45 but did not express the lymphoid markers (CD3, CD4, CD8) or myeloid markers (CD11b and CD14) which distinguishes them from 'early' endothelial progenitor cells (EPCs). Functional studies demonstrated that these naEFCs (i) bound Ulex europaeus lectin, (ii) demonstrated acetylated-low density lipoprotein uptake, (iii) increased vascular cell adhesion molecule (VCAM-1) surface expression in response to tumor necrosis factor and (iv) in co-culture with mature endothelial cells increased the number of tubes, tubule branching and loops in a 3-dimensional in vitro matrix. More importantly, naEFCs placed in vivo generated new lumen containing vasculature lined by CD144 expressing human endothelial cells (ECs). Extensive genomic and proteomic analyses of the naEFCs showed that intercellular adhesion molecule (ICAM)-3 is expressed on their cell surface but not on mature endothelial cells. Furthermore, functional analysis demonstrated that ICAM-3 mediated the rolling and adhesive events of the naEFCs under shear stress. We suggest that the distinct population of naEFCs identified and characterized here represents a new valuable therapeutic target to control aberrant vasculogenesis.

Comparison of blood and synovial fluid th17 and novel peptidase inhibitor 16 Treg cell subsets in juvenile idiopathic arthritis.

OBJECTIVE: Early recognition and treatment of juvenile idiopathic arthritis (JIA) can prevent joint damage and minimize side effects of medication. The balance between proinflammatory and antiinflammatory mechanisms is known to be important in JIA, and we therefore investigated T cell subsets including Th cells, autoaggressive Th17 cells, and regulatory T cells (Treg), including a novel Treg subset in peripheral blood (PB) and synovial fluid (SF) of patients with JIA. METHODS: Fifty children with JIA were enrolled in our study. Frequency, phenotype, and function of T lymphocytes in PB and SF were characterized using flow cytometry. Migration capabilities of PB and SF cells were compared. RESULTS: Synovial T cells showed different phenotype and function compared with PB T cells, with an increased proportion of memory T cells, expression of CCR4, CCR5, CXCR3, interleukin 23R, and an increased ratio of Th17 to Treg. Although Treg were increased in SF compared with the PB, we found a significant decrease in the numbers of peptidase inhibitor 16 (PI16)+ Treg in active joints compared with peripheral blood. Coexpression of CCR4 and CCR6 was reduced on PI16+ Treg in PB and SF of patients with JIA compared with healthy children, however the ability of these cells to migrate toward their ligands was unaffected. CONCLUSION: This is a comprehensive characterization of novel PI16+ Treg and Th17 cells in matched blood and synovial fluid samples of patients with JIA. Despite an increased number of Treg within the inflamed joint, lower numbers of PI16+ Treg but high numbers of Th17 cells might contribute to the inability to control disease.

PI16 is expressed by a subset of human memory Treg with enhanced migration to CCL17 and CCL20.

The peptidase inhibitor PI16 was shown previously by microarray analysis to be over-expressed by CD4-positive/CD25-positive Treg compared with CD4-positive/CD25-negative Th cells. Using a monoclonal antibody to the human PI16 protein, we found that PI16-positive Treg have a memory (CD45RO-positive) phenotype and express higher levels of FOXP3 than PI16-negative Treg. PI16-positive Treg are functional in suppressor assays in vitro with potency similar to PI16-negative Treg. Further phenotyping of the PI16-positive Treg revealed that the chemokine receptors CCR4 and CCR6 are expressed by more of the PI16-positive/CD45RO-positive Treg compared with PI16-negative/CD45RO-positive Treg or Th cells. PI16-positive Treg showed enhanced in vitro migration towards the inflammatory chemokines CCL17 and CCL20, suggesting they can migrate to sites of inflammation. We conclude that PI16 identifies a novel distinct subset of functional memory Treg which can migrate to sites of inflammation and regulate the pro-inflammatory response at those sites.

Maternal milk, but not formula, regulates the immune response to beta-lactoglobulin in allergy-prone rat pups.

Controversy exists regarding the timing of the introduction of allergic foods into the diet. We investigated the immune response of rat pups exposed to beta-lactoglobulin (BLG), one of the main allergenic proteins in cow milk. Brown Norway allergy-prone rats were allocated into groups: dam-reared and unchallenged (DR), DR challenged with BLG via gavage (11 mg/d), or rats fed via gastric cannula a formula containing BLG (11 mg/d). BLG was given from d 4 of life. Rats were killed at d 10, 14, or 21. Sera were assayed for total IgE, BLG-specific IgG1, and rat mucosal mast cell protease II (RMCPII; indicator of mucosal mast cell degranulation). Ileum was assessed for cytokine mRNA. Mesenteric lymph nodes (MLN) were assessed for forkhead boxP3 (Foxp3) and chemokine (C-C motif) receptor 7 (CCR7) expression by real-time PCR and immunostained for Foxp3(+) CD4(+) regulatory cells. Formula feeding compared with dam-rearing with or without oral BLG challenge resulted in significantly greater serum IgE, BLG-specific IgG1, RMCPII, and intestinal mast cells but reduced MLN Foxp3(+) cells, Foxp3, and CCR7 expression and ileal cytokines, interleukin (IL)-4, IL-10, and interferon-gamma (P < 0.05). Importantly, giving BLG in the presence of maternal milk resulted in an immune response profile similar to that of unchallenged DR rats but with greater Foxp3 and CCR7 mRNA expression and CD4(+) Foxp3(+) cells (P < 0.05). We conclude that introducing an allergenic food with breast milk reduces immunological indicators of an allergic response, whereas introduction during formula feeding generates an allergic response.

Deficiency of 6B11+ invariant NK T-cells in celiac disease.

Immunoregulatory NK T-cells are deficient in certain autoimmune diseases. The purpose of this study was to investigate any deficiency of immunoregulatory NK T-cells in celiac disease. NK T-cells were identified by flow cytometry with 6B11 and V alpha 24 markers in blood from 18 normal and 12 celiac subjects. Blood mononuclear cells were stimulated with anti-CD3/CD28 antibodies and intracellular cytokines assessed at 4 h in seven normal and eight celiac subjects. V alpha 24/GAPDH mRNA was quantitated in duodenal biopsies by real time PCR in 17 control and 13 celiac subjects. NK T-cells in celiac subjects were reduced to 30% of those in normal subjects. Intracellular IL-4, IL-10 and IL-13 increased significantly by 33-41% in normal subjects, but did not change in celiac subjects. V alpha 24/GAPDH mRNA from celiac subjects was reduced to 5% of levels in control subjects. We conclude that immunoregulatory NK T-cells are deficient in celiac disease.

Deficiency of invariant NK T cells in Crohn's disease and ulcerative colitis.

The aim of this study was to investigate whether immunoregulatory invariant NK T cells are deficient in Crohn's disease or ulcerative colitis. Blood was collected for flow cytometry from 106 Crohn's disease, 91 ulcerative colitis, and 155 control subjects. Invariant NK T cells were assessed by Valpha24 and (alpha-galactosylceramide/CD1d tetramer markers. Intracellular cytokine was measured after in vitro anti-CD3 antibody stimulation. Valpha24+ T cells were quantified in ileocolonic biopsies as mRNA by real-time PCR and by immunofluorescence. Circulating invariant NK T cells were 5.3% of the control levels in Crohn's (P < 0.001) and 7.9% of the control levels in ulcerative colitis (P < 0.001). Interleukin-4 production was impaired in Crohn's disease and ulcerative colitis. Intestinal Valpha24 mRNA expression was 7% in Crohn's disease (P < 0.05) and 9% in ulcerative colitis (P < 0.05). Intestinal Valpha24+ T cells were 23% in Crohn's disease but not reduced in ulcerative colitis. We conclude that invariant NK T cells are deficient in Crohn's disease and in ulcerative colitis.