Identification and Phenotype of MAIT Cells in Cattle and Their Response to Bacterial Infections.

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells that utilize a semi-invariant T cell receptor (TCR) α chain and are restricted by the highly conserved antigen presenting molecule MR1. MR1 presents microbial riboflavin biosynthesis derived metabolites produced by bacteria and fungi. Consistent with their ability to sense ligands derived from bacterial sources, MAIT cells have been associated with the immune response to a variety of bacterial infections, such as Mycobacterium spp., Salmonella spp. and Escherichia coli. To date, MAIT cells have been studied in humans, non-human primates and mice. However, they have only been putatively identified in cattle by PCR based methods; no phenotypic or functional analyses have been performed. Here, we identified a MAIT cell population in cattle utilizing MR1 tetramers and high-throughput TCR sequencing. Phenotypic analysis of cattle MAIT cells revealed features highly analogous to those of MAIT cells in humans and mice, including expression of an orthologous TRAV1-TRAJ33 TCR α chain, an effector memory phenotype irrespective of tissue localization, and expression of the transcription factors PLZF and EOMES. We determined the frequency of MAIT cells in peripheral blood and multiple tissues, finding that cattle MAIT cells are enriched in mucosal tissues as well as in the mesenteric lymph node. Cattle MAIT cells were responsive to stimulation by 5-OP-RU and riboflavin biosynthesis competent bacteria in vitro. Furthermore, MAIT cells in milk increased in frequency in cows with mastitis. Following challenge with virulent Mycobacterium bovis, a causative agent of bovine tuberculosis and a zoonosis, peripheral blood MAIT cells expressed higher levels of perforin. Thus, MAIT cells are implicated in the immune response to two major bacterial infections in cattle. These data suggest that MAIT cells are functionally highly conserved and that cattle are an excellent large animal model to study the role of MAIT cells in important zoonotic infections.

Variations in MHC class I antigen presentation and immunopeptidome selection pathways.

Major histocompatibility class I (MHC-I) proteins mediate immunosurveillance against pathogens and cancers by presenting antigenic or mutated peptides to antigen receptors of CD8+ T cells and by engaging receptors of natural killer (NK) cells. In humans, MHC-I molecules are highly polymorphic. MHC-I variations permit the display of thousands of distinct peptides at the cell surface. Recent mass spectrometric studies have revealed unique and shared characteristics of the peptidomes of individual MHC-I variants. The cell surface expression of MHC-I-peptide complexes requires the functions of many intracellular assembly factors, including the transporter associated with antigen presentation (TAP), tapasin, calreticulin, ERp57, TAP-binding protein related (TAPBPR), endoplasmic reticulum aminopeptidases (ERAPs), and the proteasomes. Recent studies provide important insights into the structural features of these factors that govern MHC-I assembly as well as the mechanisms underlying peptide exchange. Conformational sensing of MHC-I molecules mediates the quality control of intracellular MHC-I assembly and contributes to immune recognition by CD8 at the cell surface. Recent studies also show that several MHC-I variants can follow unconventional assembly routes to the cell surface, conferring selective immune advantages that can be exploited for immunotherapy.

Antigen Recognition by MR1-Reactive T Cells; MAIT Cells, Metabolites, and Remaining Mysteries.

Mucosal-associated Invariant T (MAIT) cells recognize vitamin B-based antigens presented by the non-polymorphic MHC class I related-1 molecule (MR1). Both MAIT T cell receptors (TCR) and MR1 are highly conserved among mammals, suggesting an important, and conserved, immune function. For many years, the antigens they recognize were unknown. The discovery that MR1 presents vitamin B-based small molecule ligands resulted in a rapid expansion of research in this area, which has yielded information on the role of MAIT cells in immune protection, autoimmune disease and recently in homeostasis and cancer. More recently, we have begun to appreciate the diverse nature of the small molecule ligands that can bind MR1, with several less potent antigens and small molecule drugs that can bind MR1 being identified. Complementary structural information has revealed the complex nature of interactions defining antigen recognition. Additionally, we now view MAIT cells (defined here as MR1-riboflavin-Ag reactive, TRAV1-2+ cells) as one subset of a broader family of MR1-reactive T cells (MR1T cells). Despite these advances, we still lack a complete understanding of how MR1 ligands are generated, presented and recognized in vivo. The biological relevance of these MR1 ligands and the function of MR1T cells in infection and disease warrants further investigation with new tools and approaches.

New insights into IVIg mechanisms and alternatives in autoimmune and inflammatory diseases.

PURPOSE OF REVIEW: Intravenous immunoglobulin (IVIg) is an effective treatment for an increasing number of autoimmune and inflammatory conditions. However, IVIg continues to be limited by problems of potential shortages and cost. A number of mechanisms have been described for IVIg, which have been captured in newly emergent IVIg mimetic and IVIg alternative therapies. This review discusses the recent developments in IVIg mimetics and alternatives. RECENT FINDINGS: Newly emergent IVIg mimetics and alternatives capture major proposed mechanisms of IVIg, including FcγR blockade, FcRn inhibition, complement inhibition, immune complex mimetics and sialylated IgG. Many of these emergent therapies have promising preclinical and clinical trial results. SUMMARY: Significant research has been undertaken into the mechanism of IVIg in the treatment of autoimmune and inflammatory disease. Understanding the major IVIg mechanisms has allowed for rational development of IVIg mimetics and alternatives for several IVIg-treatable diseases.

The biology and functional importance of MAIT cells.

In recent years, a population of unconventional T cells called 'mucosal-associated invariant T cells' (MAIT cells) has captured the attention of immunologists and clinicians due to their abundance in humans, their involvement in a broad range of infectious and non-infectious diseases and their unusual specificity for microbial riboflavin-derivative antigens presented by the major histocompatibility complex (MHC) class I-like protein MR1. MAIT cells use a limited T cell antigen receptor (TCR) repertoire with public antigen specificities that are conserved across species. They can be activated by TCR-dependent and TCR-independent mechanisms and exhibit rapid, innate-like effector responses. Here we review evidence showing that MAIT cells are a key component of the immune system and discuss their basic biology, development, role in disease and immunotherapeutic potential.

Mucosal-Associated Invariant T Cell Levels Are Reduced in the Peripheral Blood and Lungs of Children With Active Pulmonary Tuberculosis.

Mucosal associated invariant T (MAIT) cells are unconventional, semi-invariant T lymphocytes that recognize microbial-derived vitamin B2 (riboflavin) biosynthesis precursor derivatives presented by the monomorphic MHC class 1-related (MR1) molecule. Upon microbial infection, MAIT cells rapidly produce cytokines and cytotoxic effectors, and are thus important players in anti-microbial defense. MAIT cells are protective in experimental models of infection and are decreased in the blood of adult patients with bacterial infections, including Mycobacterium tuberculosis (Mtb). In children, the risk of rapid progression to active tuberculosis (TB) following Mtb infection is higher than in adults. Whether MAIT cells influence the outcome of Mtb infection in children is therefore, an important issue. We analyzed MAIT cell numbers and phenotype in 115 children investigated for pulmonary TB and determined their potential correlation with disease progression. MAIT cells were reduced in numbers and activated in the peripheral blood of children with active TB as compared to those with latent TB infection (LTBI) and healthy children. Moreover, MAIT cells did not accumulate and did not proliferate in the lung of children with active TB. These results suggest that MAIT cells may be important in preventing progression of Mtb infection to active TB in children.

Novel approaches to preclinical research and TB vaccine development.

The 4th Global Forum on TB Vaccines, convened in Shanghai, China, from 21 - 24 April 2015, brought together a wide and diverse community involved in tuberculosis vaccine research and development to discuss the current status of, and future directions for this critical effort. This paper summarizes the sessions on Low-Dose NHP Challenge Models, Novel Approaches to Animal Models for TB Vaccine R&D, Novel Antigen Delivery Strategies, and Next Generation TB Vaccines and Vaccine Concepts. Summaries of all sessions from the 4th Global Forum are compiled in a special supplement of Tuberculosis. [August 2016, Vol 99, Supp S1, S1-S30].

Self-adjuvanted nanovaccine for cancer immunotherapy: Role of lysosomal rupture-induced ROS in MHC class I antigen presentation.

MHC class I (MHC I) antigen presentation of exogenous antigens (so called "cross presentation") is a central mechanism of CD8(+) cytotoxic T lymphocyte (CTL) responses essential for successful vaccine-based cancer immunotherapy. The present study constructed amphiphilic pH-sensitive galactosyl dextran-retinal (GDR) nanogels for cancer vaccine delivery, in which dextran was conjugated with all-trans retinal (a metabolite of vitamin A) through a pH-sensitive hydrazone bond, followed by galactosylation to acquire dendritic cell (DC)-targeting ability. Our results showed that pH-sensitive GDR nanogel was a self-adjuvanted vaccine carrier that not only promoted DC maturation through activating retinoic acid receptor (RAR) signaling, but also facilitated antigen uptake and cytosolic antigen release in DCs. Furthermore, pH-sensitive GDR nanogel effectively augmented MHC I antigen presentation and evoked potent anti-cancer immune responses in vivo. More importantly, we first reported that nanoparticle-triggered lysosome rupture could directly induce ROS production in DCs, which was found to be essential for augmenting proteasome activity and downstream MHC I antigen presentation. Hence, DC-targeted pH-sensitive GDR nanogels could be a potent delivery system for cancer vaccine development. Triggering lyososomal rupture in DCs with pH-sensitive nanoparticles might be a plausible strategy to elevate intracellular ROS production for promoting antigen cross presentation, thereby improving cancer vaccine efficacy.

Loss of Nrf2 in bone marrow-derived macrophages impairs antigen-driven CD8(+) T cell function by limiting GSH and Cys availability.

NF-E2-related factor 2 (Nrf2), known to protect against reactive oxygen species, has recently been reported to resolve acute inflammatory responses in activated macrophages. Consequently, disruption of Nrf2 promotes a proinflammatory macrophage phenotype. In the current study, we addressed the impact of this macrophage phenotype on CD8(+) T cell activation by using an antigen-driven coculture model consisting of Nrf2(-/-) and Nrf2(+/+) bone marrow-derived macrophages (BMDMΦ) and transgenic OT-1 CD8(+) T cells. OT-1 CD8(+) T cells encode a T cell receptor that specifically recognizes MHC class I-presented ovalbumin OVA(257-264) peptide, thereby causing a downstream T cell activation. Interestingly, coculture of OVA(257-264)-pulsed Nrf2(-/-) BMDMΦ with transgenic OT-1 CD8(+) T cells attenuated CD8(+) T cell activation, proliferation, and cytotoxic function. Since the provision of low-molecular-weight thiols such as glutathione (GSH) or cysteine (Cys) by macrophages limits antigen-driven CD8(+) T cell activation, we quantified the amounts of intracellular and extracellular GSH and Cys in both cocultures. Indeed, GSH levels were strongly decreased in Nrf2(-/-) cocultures compared to wild-type counterparts. Supplementation of thiols in Nrf2(-/-) cocultures via addition of glutathione ester, N-acetylcysteine, ß-mercaptoethanol, or cysteine itself restored T cell proliferation as well as cytotoxicity by increasing intracellular GSH. Mechanistically, we identified two potential Nrf2-regulated genes involved in thiol synthesis in BMDMΦ: the cystine transporter subunit xCT and the modulatory subunit of the GSH-synthesizing enzyme γ-GCS (GCLM). Pharmacological inhibition of γ-GCS-dependent GSH synthesis as well as knockdown of the cystine antiporter xCT in Nrf2(+/+) BMDMΦ mimicked the effect of Nrf2(-/-) BMDMΦ on CD8(+) T cell function. Our findings demonstrate that reduced levels of GCLM as well as xCT in Nrf2(-/-) BMDMΦ limit GSH availability, thereby inhibiting antigen-induced CD8(+) T cell function.

HLA class I expression and its alteration by preoperative hyperthermo-chemoradiotherapy in patients with rectal cancer.

OBJECTIVE: Enhancing immunologic responses, including human leukocyte antigen (HLA) class I expression on tumor cells and recognition and elimination of tumor cells by tumor-specific cytotoxic T lymphocyte (CTL), is considered a novel concept of radiotherapy. The present study examined patients who underwent preoperative hyperthermo-chemoradiotherapy (HCRT) for locally advanced rectal cancer to assess the correlation between HLA class I expression and clinical outcome. MATERIALS AND METHODS: Seventy-eight patients with locally advanced rectal adenocarcinoma who received preoperative HCRT were enrolled. The median age of the patients was 64 years (range, 33-85 years) and 4, 18, and 56 patients had clinical stage I, II and III disease, respectively. Formalin-fixed and paraffin-embedded tissues excised before and after HCRT were subjected to immunohistochemical analysis with an anti-HLA class I-A, B, C antibody. HLA class I expression was graded according to tumor cell positivity. RESULTS: In pre-HCRT, the number of specimens categorized as Grade 0 and 1 were 19 (24%) and 58 (74%), respectively. Only 1 patient (1%) showed Grade 2 expression. However, 6 (8%), 27 (35%), 7 (9%), and 12 (15%) post-HCRT specimens were graded as Grade 0, 1, 2, and 3, respectively. There was a significant increase in HLA class I expression in post-HCRT specimens (p<0.01). However, neither pre- nor post-HCRT HLA class I expression affected overall survival and distant metastasis-free survival in clinical stage III patients. Univariate analysis revealed that Post-HCRT HLA class I expression showed a significant negative relationship with LC (p<0.05). Nevertheless, multivariate analysis showed that there was no correlation between HLA class I expression and clinical outcome. CONCLUSION: HCRT increased HLA class I expression in rectal cancer patients. However, multivariate analysis failed to show any correlation between the level of HLA class I expression and prognosis.

In vivo blockade of the programmed cell death-1 pathway using soluble recombinant PD-1-Fc enhances CD4+ and CD8+ T cell responses but has limited clinical benefit.

The programmed cell death-1 (PD-1)/programmed cell death ligand-1 pathway has been shown to limit cell-mediated effector functions during chronic viral infections impeding clearance of pathogens. As a strategy to reverse this exhaustion and increase T cell polyfunctionality, PD-1 ligands were blocked in vivo using a recombinant macaque PD-1 fused to a macaque Ig-Fc (rPD-1-Fc) in SIVmac239-infected rhesus macaques during the early chronic phase of infection, either alone or in combination with antiretroviral therapy. In vitro blockade showed improvement of Ag-specific CD4(+) and CD8(+) T cells from monkeys chronically infected with SIV. Of note, a prolonged 5-d blockade in culture was beneficial for both gag-specific CD4(+) and CD8(+) T cells based on proliferation and dual cytokine production. Although the in vivo administration of rPD-1-Fc induced enhanced SIV-specific CD4 and CD8 T cell proliferation both in the blood and gut, it failed to alter plasma viremia. However, rPD-1-Fc administration in the context of antiretroviral therapy interruption induced a significant delay of viral load rebound. In addition, rPD-1-Fc administration in MamuA*001(+) monkeys led to both an increase in the frequencies and Ki67 expression of GagCM9(+) CD8(+) T cells in the blood and rectal mucosa and polyfunctionality of GagCM9(+) CD8(+) T cells in blood. In conclusion, however, our data suggest that PD-1/programmed cell death ligand-1 blockade using soluble rPD-1-Fc instead of anti-PD-1 mAb, although effective in rescuing the effector function of SIV-specific CD4(+) and CD8(+) T cells during the early chronic phase of infection, has limited clinical benefit.

Enhanced sensitivity of colon tumour cells to natural killer cell cytotoxicity after mild thermal stress is regulated through HSF1-mediated expression of MICA.

PURPOSE: Previously we showed that mild thermal stress increased natural killer (NK) cell-mediated tumour cytotoxicity and that this could be blocked by anti-NKG2D or anti-MICA (major histolocompatability complex (MHC) class I related chain A) antibodies. Here, we investigated the role of the transcription factor heat shock factor 1 (HSF1) in thermal regulation of MICA expression in tumour cells in vitro and in vivo. MATERIALS AND METHODS: Hyperthermia experiments were conducted in vitro and in mice using a target temperature of 39.5 °C. Apoptotic cells and NK cells in situ were visualised by use of the TUNEL assay or expression of NKp46 respectively. Using Colo205 cells, HSF1 message was blocked utilising siRNA while luciferase reporter assays were used to measure the activity of the MICA promoter in vitro. Cell surface MICA was measured by flow cytometry. RESULTS: Following whole body hyperthermia (WBH), tumour tissues showed an increase in NK cells and apoptosis. Mild thermal stress resulted in a transient increase in surface MICA and enhanced NK cytotoxicity of the Colo205 colon cancer cell line. Silencing (mRNA) HSF1 expression in Colo205 cells prevented the thermal enhancement of MICA message and surface protein levels, with partial loss of thermally enhanced NK cytotoxicity. Mutations of the HSF1 binding site on the MICA promoter implicated HSF1 in the thermal enhancement of MICA. Some, but not all, patient-derived colon tumour derived xenografts also exhibited an enhanced MICA message expression after WBH. CONCLUSIONS: Up-regulation of MICA expression in Colo205 cells and enhanced sensitivity to NK cell killing following mild thermal stress is dependent upon HSF1.

Different peripheral tissue injury induces differential phenotypic changes of spinal activated microglia.

The purpose of this study is to investigate the possible different cellular marker expression associated with spinal cord microglial activation in different pain models. Immunohistochemistry and western blotting analysis of CD45, CD68, and MHC class I antigen as well as CD11b and Iba-1 in the spinal cord were quantitatively compared among widely used three pain animal models, complete Freund's adjuvant (CFA) injection, formalin injection, and chronic constriction injury (CCI) models. The results showed that significant upregulated expressions of CD45 and MHC class I antigen in spinal microglia as well as morphological changes with increased staining with CD11b and Iba-1 were seen in CCI and formalin models and not found in CFA-induced inflammatory pain model. CD68 expression was only detected in CCI model. Our findings suggested that different peripheral tissue injuries produced differential phenotypic changes associated with spinal microglial activation; peripheral nerve injury might induce spinal microglia to acquire these immunomolecular phenotypic changes.

The yin-yang of KIR3DL1/S1: molecular mechanisms and cellular function.

Killer Immunoglobulin-like Receptors (KIR) are a family of receptors expressed on natural killer (NK) and T-cell subsets. KIR3DL1 is a highly polymorphic receptor that binds to groups of HLAA and HLA-B allotypes that express the Bw4 epitope. The variation in KIR3DL1 allotypes manifests at a number of levels. Most dramatically, a common allelic variant encodes an activating rather than an inhibitory receptor (KIR3DS1). In addition, sequence variants can affect both the frequency of expression within the NK cell population and the intensity of expression on a given cell. KIR3DL1 polymorphism also influences the interaction with HLA-Bw4 molecules, due to contacts with the HLA molecule itself and sensitivity to the presented peptide. A body of evidence from genetic association studies supports the biological significance not only of the interaction of KIR3DL1 with HLA-Bw4 but also the functional variation seen with different KIR3DL1 and HLA allotypes. In this review, we discuss our current understanding of KIR3DL1 function and our recent insights from the structure of the KIR3DL1 in complex with HLA. In addition, we will summarize our current understanding of KIR3DS1, including its ligand specificity and its role in immune responses.

Discovery and structure-activity relationships of small molecules that block the human immunoglobulin G-human neonatal Fc receptor (hIgG-hFcRn) protein-protein interaction.

The neonatal Fc receptor, FcRn, prolongs the half-life of IgG in the serum and represents a potential therapeutic target for the treatment of autoimmune disease. Small molecules that block the protein-protein interactions of human IgG-human FcRn may lower pathogenic autoantibodies and provide effective treatment. A novel class of quinoxalines has been discovered as antagonists of the IgG:FcRn protein-protein interaction through optimization of a hit derived from a virtual ligand-based screen.

Immunophenotyping and characterization of BNP colostra revealed pathogenic alloantibodies of IgG1 subclass with specifity to platelets, granulocytes and monocytes of all maturation stages.

Bovine neonatal pancytopenia (BNP) is mainly characterized by multiple haemorrhages, thrombocytopenia and leukocytopenia as a result of bone marrow depletion. BNP can be induced in healthy calves through application of colostrum from BNP donors, proofing that BNP is mediated to maternal alloantibodies. Alloantibody binding to bovine blood cells is present in sera and colostra of BNP donors and is probably initialized by vaccination with a certain BVD vaccine. To understand etiology and pathomechanisms of BNP, we closely characterized disease inducing antibodies regarding immunoglobulin subclass and binding specificities to peripheral blood derived leukocytes and platelets. By exact phenotyping the targeted blood cell subsets, including platelets for the first time, we investigated that BNP alloantibodies are exclusively of IgG1 subclass. Interestingly, IgG1 of BNP colostra bound to 70% leukocytes and 100% platelets irrespective of different bovine breeds and cellular maturity of all specimens tested. Furthermore, staining pattern on platelets as well as leukocyte subsets by BNP-IgG1 alloantibody exposed 100% reactivity to platelets, granulocytes and monocytes. Interestingly, the main part of T-helper cells was not bound by colostral alloantibodies. Our results point to a crucial role of IgG1 antibodies in BNP and to a target antigen that is expressed by all cells of myeloid lineage, but only partially by the lymphoid lineage.

Robust recombinant FcRn production in mammalian cells enabling oriented immobilization for IgG binding studies.

The MHC class-I related receptor or neonatal Fc receptor (FcRn) protects IgG and albumin from degradation by rescuing them in endothelial cells in a pH dependent fashion and consequently increases their respective half-lives. Monoclonal antibody-based therapies are of increasing interest and characterizing the interaction with FcRn is important for the development of an antibody candidate. In order to facilitate the production of soluble FcRn suitable for interaction studies, we generated semi-stable pools co-expressing FcRn α-chain, ß2-microglobulin, biotin ligase and EGFP using a dual promoter, multi-cistronic vector. Human and mouse FcRn were purified in the mg/L range of culture medium and a single purification step was sufficient to reach a high level of purity. The receptors were characterized by ELISA, flow cytometry and surface plasmon resonance and shown to be functional. The single site biotinylation facilitated the directional immobilization of FcRn on the sensor chip and significantly increased the response level of the surface compared to amine coupling used in previous studies. Using this system, the affinity constants of seven IgGs, from various species and isotypes, were determined for human and mouse FcRn, including two hamster isotypes. These results confirm the higher selectivity of the human receptor and the promiscuous binding of mFcRn to IgGs from different species.

The immunological impact of neoadjuvant chemotherapy on the tumor microenvironment of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal cancer is an aggressive cancer with poor prognosis. However, little is known about the immune response in the tumor microenvironment after neoadjuvant chemotherapy. PURPOSE: To investigate the immunological impact of neoadjuvant chemotherapy in the tumor microenvironment of esophageal squamous cell carcinoma. METHODS: Eighteen patients with esophageal squamous cell carcinoma with and without neoadjuvant chemotherapy were analyzed using immunohistochemical methods for human leukocyte antigen (HLA) class I heavy chain, CD4-, CD8-, and Foxp3-positive cell infiltration. RESULTS: The number of CD4 T cells in the stroma and within the cancer nest was significantly higher in the neoadjuvant chemotherapy group. The number of CD8 T cells in the stroma was significantly higher in the neoadjuvant chemotherapy group. HLA class I expression was more downregulated in the control group compared with the neoadjuvant chemotherapy group. CONCLUSION: Neoadjuvant chemotherapy utilizing 5-fluorouracil and cisplatin in esophageal squamous cell carcinoma is useful to induce CD4 and CD8 T lymphocytes in the tumor microenvironment and to maintain HLA class I expression levels in combination with its direct cytotoxic effects.

Influenza A/H1N1 vaccine in patients treated by kidney transplant or dialysis: a cohort study.

BACKGROUND AND OBJECTIVES: In 2009, the pandemic influenza A/H1N1 accounted for worldwide recommendations about vaccination. There are few data concerning the immunogenicity or the security of the adjuvanted-A/H1N1 vaccine in transplanted and hemodialyzed patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Sera from 21 controls, 53 hemodialyzed (HD) patients, and 111 renal transplant recipients (RT) were sampled before (T0) and 1 month after (T1) a single dose of Pandemrix® vaccine (GSK Biologicals, AS03-adjuvanted). We measured the neutralizing antibodies against A/H1N1/2009, the geometric mean (GM) titers, the GM titer ratios (T1/T0) with 95% confidence intervals, and the seroconversion rate (responders: ≥4-fold increase in titer). The HLA and MICA immunization was determined by Luminex technology. RESULTS: The GM titer ratio was 38 (19 to 78), 9 (5 to 16), and 5 (3 to 6) for controls, HD patients, and RT patients, respectively (P < 0.001). The proportion of responders was 90%, 57%, and 44%, respectively (P < 0.001). In RT patients, the prevalence of histocompatibility leukocyte antigen (HLA) class I, histocompatibility leukocyte antigen class II, and MHC class I-related chain A immunization, was, respectively, 15%, 14%, and 14% before and 14%, 14%, and 11% after vaccination (P = 1, 1, and 0.39). CONCLUSIONS: The influenza A/H1N1-adjuvanted vaccine is of limited efficacy but is safe in renal disease populations. The humoral response is lower in transplanted versus hemodialyzed patients. Further studies are needed to improve the efficacy of vaccination in those populations.

Reversal of atopic dermatitis with narrow-band UVB phototherapy and biomarkers for therapeutic response.

BACKGROUND: Atopic dermatitis (AD) is a common inflammatory skin disease exhibiting a predominantly T(H)2/"T22" immune activation and a defective epidermal barrier. Narrow-band UVB (NB-UVB) is considered an efficient treatment for moderate-to-severe AD. In patients with psoriasis, NB-UVB has been found to suppress T(H)1/T(H)17 polarization, with subsequent reversal of epidermal hyperplasia. The immunomodulatory effects of this treatment are largely unknown in patients with AD. OBJECTIVE: We sought to evaluate the effects of NB-UVB on immune and barrier abnormalities in patients with AD, aiming to establish reversibility of disease and biomarkers of therapeutic response. METHODS: Twelve patients with moderate-to-severe chronic AD received NB-UVB phototherapy 3 times weekly for up to 12 weeks. Lesional and nonlesional skin biopsy specimens were obtained before and after treatment and evaluated by using gene expression and immunohistochemistry studies. RESULTS: All patients had at least a 50% reduction in SCORAD index scores with NB-UVB phototherapy. The T(H)2, T22, and T(H)1 immune pathways were suppressed, and measures of epidermal hyperplasia and differentiation normalized. The reversal of disease activity was associated with elimination of inflammatory leukocytes and T(H)2/T22- associated cytokines and chemokines and normalized expression of barrier proteins. CONCLUSIONS: Our study shows that resolution of clinical disease in patients with chronic AD is accompanied by reversal of both the epidermal defects and the underlying immune activation. We have defined a set of biomarkers of disease response that associate resolved T(H)2 and T22 inflammation in patients with chronic AD with reversal of barrier pathology. By showing reversal of the AD epidermal phenotype with a broad immune-targeted therapy, our data argue against a fixed genetic phenotype.