Down-regulation of locus-specific human lymphocyte antigen class I expression in Epstein-Barr virus-associated gastric cancer: implication for viral-induced immune evasion

The tumor immune composition of mismatch repair deficient and Epstein-Barr virus-positive gastric cancer: A systematic review

BACKGROUND

Gastric cancer (GC), known for its unfavorable prognosis, has been classified in four distinct molecular subtypes. These subtypes not only exhibit differences in their genome and transcriptome but also in the composition of their tumor immune microenvironment. The microsatellite instable (MSI) and Epstein-Barr virus (EBV) positive GC subtypes show clear clinical benefits from immune checkpoint blockade, likely due to a neoantigen-driven and virus-driven antitumor immune response and high expression of immune checkpoint molecule PD-L1. However, even within these subtypes response to checkpoint inhibition is variable, which is potentially related to heterogeneity in the tumor immune microenvironment (TIME) and expression of co-inhibitory molecules. We conducted a systematic review to outline the current knowledge about the immunological features on the TIME of MSI and EBV + GCs.

METHODS

A systematic search was performed in PubMed, EMBASE and Cochrane Library. All articles from the year 1990 and onwards addressing immune features of gastric adenocarcinoma were reviewed and included based on predefined in- and exclusion criteria.

RESULTS

In total 5962 records were screened, of which 139 were included that reported immunological data on molecular GC subtypes. MSI and EBV + GCs were reported to have a more inflamed TIME compared to non-MSI and EBV- GC subtypes. Compared to microsatellite stable (MSS) tumors, MSI tumors were characterized by higher numbers of CD8 + and FoxP3 + T cells, and tumor infiltrating pro- and anti-inflammatory macrophages. HLA-deficiency was most common in MSI tumors compared to other molecular GC subtypes and associated with lower T and B cell infiltrates compared to HLA-proficient tumors. EBV + was associated with a high number of CD8 + T cells, Tregs, NK cells and macrophages. Expression of PD-L1, CTLA-4, Granzyme A and B, Perforin and interferon-gamma was enriched in EBV + tumors. Overall, MSI tumors harbored a more heterogeneous TIME in terms of immune cell composition and immune checkpoints compared to the EBV + tumors.

DISCUSSION AND CONCLUSION

MSI and EBV + GCs are highly Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration.; 2019pro-inflammatory immune cell populations. Although studies on the direct comparison of EBV + and MSI tumors are limited, EBV + tumors show less intra-subgroup heterogeneity compared to MSI tumors. More studies are needed to identify how Intra-subgroup heterogeneity impacts response to immunotherapy efficacy.

Role of HLA-I Structural Variants and the Polyreactive Antibodies They Generate in Immune Homeostasis

Cell-surface HLA-I molecules consisting of β2-microglobulin (β2m) associated heavy chains (HCs), referred to as Face-1, primarily present peptides to CD8+ T-cells. HCs consist of three α-domains, with selected amino acid sequences shared by all alleles of all six isoforms. The cell-surface HLA undergoes changes upon activation by pathological conditions with the expression of β2m-free HCs (Face-2) resulting in exposure of β2m-masked sequences shared by almost all alleles and the generation of HLA-polyreactive antibodies (Abs) against them. Face-2 may homodimerize or heterodimerize with the same (Face-3) or different alleles (Face-4) preventing exposure of shared epitopes. Non-allo immunized males naturally carry HLA-polyreactive Abs. The therapeutic intravenous immunoglobulin (IVIg) purified from plasma of thousands of donors contains HLA-polyreactive Abs, admixed with non-HLA Abs. Purified HLA-polyreactive monoclonal Abs (TFL-006/007) generated in mice after immunizing with Face-2 are documented to be immunoregulatory by suppressing or activating different human lymphocytes, much better than IVIg. Our objectives are (a) to elucidate the complexity of the HLA-I structural variants, and their Abs that bind to both shared and uncommon epitopes on different variants, and (b) to examine the roles of those Abs against HLA-variants in maintaining immune homeostasis. These may enable the development of personalized therapeutic strategies for various pathological conditions.

EBNA2 driven enhancer switching at the CIITA-DEXI locus suppresses HLA class II gene expression during EBV infection of B-lymphocytes

Viruses suppress immune recognition through diverse mechanisms. Epstein-Barr Virus (EBV) establishes latent infection in memory B-lymphocytes and B-cell malignancies where it impacts B-cell immune function. We show here that EBV primary infection of naïve B-cells results in a robust down-regulation of HLA genes. We found that the viral encoded transcriptional regulatory factor EBNA2 bound to multiple regulatory regions in the HLA locus. Conditional expression of EBNA2 correlated with the down regulation of HLA class II transcription. EBNA2 down-regulation of HLA transcription was found to be dependent on CIITA, the major transcriptional activator of HLA class II gene transcription. We identified a major EBNA2 binding site downstream of the CIITA gene and upstream of DEXI, a dexamethasone inducible gene that is oriented head-to-head with CIITA gene transcripts. CRISPR/Cas9 deletion of the EBNA2 site upstream of DEXI attenuated CIITA transcriptional repression. EBNA2 caused an increase in DEXI transcription and a graded change in histone modifications with activation mark H3K27ac near the DEXI locus, and a loss of activation marks at the CIITA locus. A prominent CTCF binding site between CIITA and DEXI enhancers was mutated and further diminished the effects of EBNA2 on CIITA. Analysis of HiC data indicate that DEXI and CIITA enhancers are situated in different chromosome topological associated domains (TADs). These findings suggest that EBNA2 down regulates HLA-II genes through the down regulation of CIITA, and that this down regulation is an indirect consequence of EBNA2 enhancer formation at a neighboring TAD. We propose that enhancer competition between these neighboring chromosome domains represents a novel mechanism for gene regulation demonstrated by EBNA2.

Isolation of lymphocytes from the human gastric mucosa

Flow cytometry is widely used for lymphocyte immunophenotyping in clinical settings. However, few studies have applied it for analyzing lymphocytes of the gastric mucosa. This review offers an overview of methodologies for isolating lymphocytes from the human stomach. Previously reported articles were reviewed, focusing on procedures for isolating human gastric mucosal lymphocytes. Helicobacter pylori-associated peptic diseases and gastric cancer are two major subjects of research in this field. Enzymatic dissociation, mechanical dissociation, or a combination of the two have been used to isolate lymphocytes from the stomach. Intra-epithelial and lamina propria lymphocytes were separately isolated in several studies. We also summarize the history and present trends in analyzing lymphocytes in patients with gastric disease.

Cytomegalovirus replication is associated with enrichment of distinct γδ T cell subsets following lung transplantation: A novel therapeutic approach?

BACKGROUND

Anti-viral treatments to control cytomegalovirus (CMV) after lung transplantation (LTx) are associated with toxicity and anti-viral resistance. Cellular immunotherapy with virus-specific cytotoxic T cells has yielded promising results but requires donor/recipient matching. γδ T cells are involved in anti-viral immunity and can recognize antigens independently of major histocompatibility complex molecules and may not require the same level of matching. We assessed the phenotype of circulating γδ T cells after LTx to identify the candidate populations for CMV immunotherapy.

METHODS

Peripheral blood mononuclear cells were isolated from lung transplant recipients before transplantation and at routine bronchoscopies after LTx. Patients were stratified by risk of CMV disease into moderate risk (recipient CMV seropositive, n = 15) or high risk (HR) (recipient CMV seronegative/donor CMV seropositive, n = 10). CMV replication was classified as polymerase chain reaction positive (>150 copies/ml) in blood and/or bronchoalveolar lavage within the first 18 months. The phenotype of γδ T cells was assessed by multicolor flow cytometry, and T-cell receptor (TCR) sequences were determined by deep sequencing.

RESULTS

In HR lung transplant recipients with CMV replication, we observed striking phenotypic changes in γδ T cells, marked by an increase in the proportion of effector Vδ1+ γδ T cells expressing the activating natural killer cell receptor NKG2C. Moreover, we observed a remarkable increase in TCR diversity.

CONCLUSIONS

NKG2C+ Vδ1+ γδ T cells were associated with CMV replication and may indicate their potential to control infection. As such, we propose that they could be a potential target for cellular therapy against CMV.

Downregulation of HLA-ABC expression through promoter hypermethylation and downmodulation of MIC-A/B surface expression in LMP2A-positive epithelial carcinoma cell lines

Epstein Barr Virus (EBV) is a human herpesvirus, and has been reported to be associated with nasopharyngeal carcinoma, gastric carcinoma, Burkitt’s lymphoma and Hodgkin’s lymphoma. In most of the associated tumors, the virus remains in a latently infected state. During latency, EBV expresses Latent Membrane Protein 2A (LMP2A) along with few other genes. We previously showed that LMP2A causes downregulation of HLA-ABC surface expression in EBV associated gastric carcinomas. However, the mechanism that leads to this downregulation remain unclear. We therefore analyzed methylation-mediated regulation of HLA-ABC expression by LMP2A. Interestingly, according to the ‘missing self’ hypothesis, when there is a decrease in HLA-ABC surface expression, expression of NKG2D ligands’ must be upregulated to facilitate killing by Natural Killer (NK) cells. Analysis of NKG2D ligands’ expression, revealed downregulation of MIC-A/B surface expression in response to LMP2A. Furthermore, the role of Unfolded Protein Response (UPR) in the regulation of MIC-A/B surface expression in cells expressing LMP2A was also investigated. Protein Disulfide Isomerase (PDI) mediated inhibition of MIC-A/B surface expression was observed in LMP2A expressing cells. Our current findings provide new insights in LMP2A arbitrated dysregulation of host immune response in epithelial cell carcinomas.

High Levels of Class I Major Histocompatibility Complex mRNA Are Present in Epstein-Barr Virus-Associated Gastric Adenocarcinomas

Epstein–Barr virus (EBV) is responsible for approximately 9% of stomach adenocarcinomas. EBV-encoded microRNAs have been reported as reducing the function of the class I major histocompatibility complex (MHC-I) antigen presentation apparatus, which could allow infected cells to evade adaptive immune responses. Using data from nearly 400 human gastric carcinomas (GCs), we assessed the impact of EBV on MHC-I heavy and light chain mRNA levels, as well as multiple other components essential for antigen processing and presentation. Unexpectedly, mRNA levels of these genes were as high, or higher, in EBV-associated gastric carcinomas (EBVaGCs) compared to normal control tissues or other GC subtypes. This coordinated upregulation could have been a consequence of the higher intratumoral levels of interferon γ in EBVaGCs, which correlated with signatures of increased infiltration by T and natural killer (NK) cells. These results indicate that EBV-encoded products do not effectively reduce mRNA levels of the MHC-I antigen presentation apparatus in human GCs.

Individualized immune-related gene signature predicts immune status and oncologic outcomes in clear cell renal cell carcinoma patients

OBJECTIVE

To develop an individualized immune-related gene signature that predicts oncologic outcomes and immune status of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

The immune-related gene pair (IGP) index was constructed and validated based on pairwise comparison in 634 ccRCC patients. Association with overall survival (OS), progression-free interval (PFI), and disease-specific survival (DSS) was evaluated by Kaplan-Meier analysis, univariate and multivariate cox regression survival analysis. Prognostic values of different risk models were compared using Harrell's C-index.

RESULTS

The IGP index of 17 gene pairs was an adverse independent risk factor in multivariate analyses for OS (hazard ratio [HR], 1.718; P = 0.001), PFI (HR, 1.550; P = 0.006), and DSS (HR, 2.201; P = 0.001) in ccRCC patients. It showed comparable prognostic accuracy with ccA/ccB signature (C-index for OS, 0.657 vs. 0.640; P = 0.686) and better intratumor homogeneity. Immunosuppressive immune cell, markers, and pathways were all enriched in high immune-risk tumors. The integrated immune-clinical prognostic score outperformed ccA/ccB signature and University of California Integrated Staging System risk model in terms of C-index for estimation of OS, PFI, and DSS (P < 0.001).

CONCLUSIONS

The proposed IGP index is a robust and promising biomarker for estimating oncologic outcomes in ccRCC. High immune-risk tumors are immunosuppressive.

Epstein-Barr virus latent membrane protein 2A mediated activation of Sonic Hedgehog pathway induces HLA class Ia downregulation in gastric cancer cells

One of the immune evasion strategies manifested by malignant cells is the downregulation of the Human Leukocyte Antigen (HLA). HLA Class I (HLA- A, -B, -C) present endogenous peptides including viral and tumor antigens to cytotoxic T lymphocytes for immune mediated destruction. We have found the Epstein Barr Virus (EBV) Latent Membrane Protein 2A (LMP2A) to be responsible for this HLA downregulation in gastric cancer cells. Our results further indicate the Sonic Hedgehog pathway; primarily Gli1 to bring about the LMP2A mediated decrease in HLA expression.

The Monospecificity of Novel Anti-HLA-E Monoclonal Antibodies Enables Reliable Immunodiagnosis, Immunomodulation of HLA-E, and Upregulation of CD8+ T Lymphocytes

In human cancers, over-expression of HLA-E is marked by gene expression. However, immunolocalization of HLA-E on tumor cells is impeded by the HLA-Ia reactivity of commercial anti-HLA-E monoclonal antibodies (MAbs). So there was a clear need to develop monospecific anti-HLA-E MAbs for reliable immunodiagnosis of HLA-E, particularly considering the prognostic relevance of HLA-E in human cancer. HLA-E overexpression is correlated with disease progression and poor survival of patients, both of which are attributed to the suppression of anti-tumor activity of cytotoxic T cells mediated by HLA-E. The suppression mechanism involves the binding of HLA-E-specific amino acids located on the α1 and α2 helices of HLA-E to the inhibitory receptors (CD94/NKG2a) on CD8+ T lymphocytes. An anti-HLA-E MAb that recognizes these HLA-E-specific sequences can not only be a monospecific MAb with potential for specific immunolocalization of HLA-E but can also block the sequences from interacting with the CD94/NKG2a receptors. We therefore developed several clones that secrete such HLA-E-specific MAbs; then we assessed the ability of the MAbs to bind to the amino acid sequences interacting with the CD94/NKG2a receptors by inhibiting them from binding to HLA-E with peptides that inhibit receptor binding. Elucidation of the immunomodulatory capabilities of these monospecific MAbs showed that they can induce proliferation of CD8+ T cells with or without co-stimulation. These novel MAbs can serve a dual role in combating cancer by blocking interaction of HLA-E with CD94/NKG2a and by promoting proliferation of both non-activated and activated CD8+ cytotoxic αβ T cells.

Gastric cancer progression may involve a shift in HLA-E profile from an intact heterodimer to β2-microglobulin-free monomer

Phenotypic expression of human leukocyte antigen (HLA)-E on the surface of tumor lesions includes intact heterodimer [HLA-E heavy chain and β2-microglobulin (β2m)] and β2m-free monomer. Anti-HLA-E monoclonal antibodies (mAbs), MEM-E/02 or 3D12 bind to the peptide sequences in β2m-free HLA-E, which is common and shared with HLA-Ia monomers. A newly developed monospecific anti-HLA-E mAb (TFL-033) recognizes HLA-E-restricted peptide sequences on α1 and α2 helices away from β2-m-site. Tumor progression may involve shedding of β2-m from HLA-E or overexpression of β2m-free monomers. There is a need to identify and distinguish the different phenotypic expression of HLA-E, particularly the intact heterodimer from the β2m-free monomer on the surface of tumor lesions. Because of the unique peptide-binding affinities of the mAbs, it is hypothesized that TFL-033 and MEM-E/02 may distinguish the phenotypic expressions of cell surface HLA-E during stages of tumor progression. Only TFL-033 stained diffusely the cytoplasm of normal mucosa. The incidence and intensity of TFL-033 staining of the cell surface in early stages, poorly or undifferentiated and non-nodal lesions and in diffuse carcinoma is greater than that of MEM-E/02. Whereas MEM-E/02 stained terminal stages, adenocarcinoma and lymph node metastatic lesions intensely, either owing to increased expression of β2m-free HLA-E with tumor progression or owing to expression of HLA-Ia molecules. Our study evaluates the relative diagnostic potential of HLA-E-monospecific TFL-033 and the HLA-Ia-reactive MEM-E/02 for determining the specific distribution and immunodiagnosis of different phenotypic expression HLA-E in tumor lesions, and the structural and functional alterations undergone by HLA-E during tumor progression.

Etiological factors of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common disease among southern Chinese. The major etiological factors proposed for NPC pathogenesis include genetic susceptibility, environment factors and EBV infection. In the high risk population, genetic susceptibility to NPC has been mapped to the HLA loci and adjacent genes in MHC region on chromosome 6p21. Consumption of preserved food including salted fish has been implicated in its etiology in earlier studies. Its contribution to pathogenesis of NPC remains to be determined. A decreasing trend of NPC incidence was observed in Hong Kong, Taiwan and Singapore in recent years which may be accounted by a change of dietary habits. A comprehensive epidemiological study will help to elucidate the relative importance of various risk factors in the pathogenesis of NPC. Despite the close association of EBV infection with NPC, the etiological role of EBV in NPC pathogenesis remains enigmatic. EBV infection in primary nasopharyngeal epithelial cells is uncommon and difficult to achieve. EBV does not transform primary nasopharyngeal epithelial cells into proliferative clones, which contrasts greatly with the well-documented ability of EBV to transform and immortalize primary B cells. Genetic alterations identified in premalignant nasopharyngeal epithelium may play crucial roles to support stable EBV infection. Subsequently, latent and lytic EBV gene products may drive clonal expansion and transformation of premalignant nasopharyngeal epithelial cells into cancer cells. Stromal inflammation in nasopharyngeal mucosa is believed to play an important role in modulating the growth and possibly drive the malignant transformation of EBV-infected nasopharyngeal epithelial cells. Furthermore, there are increasing evidences supporting a role of EBV infection to evade host immune surveillance. EBV-infected cells may have selective growth advantages in vivo by acquiring a stress-resistance phenotype. Understanding the etiological factors and pathogenesis of NPC will contribute effectively to the prevention and treatment of this disease.

Epstein-Barr virus-encoded small non-coding RNAs induce cancer cell chemoresistance and migration

Epstein-Barr virus (EBV) encoded small, non-coding, non-polyadenylated RNAs, known as EBERs are the most abundantly expressed viral transcripts in latently EBV infected cells. We found the specific role of EBERs in cell cycle progression, resistance against chemotherapeutic drug and cellular invasion in gastric cancer cells in vitro. Ectopic expression of EBERs upregulates the expression of IL-6 and activate its downstream STAT3, which is significantly involved in downregulating the expression of cell cycle inhibitor genes p21 and p27. Stable expression of EBERs regulates the activation of pFAK and pPAK1 and the expression of anti-metastatic genes RhoGDI and KAI-1 in gastric cancer cells. In addition, administration of neu-IL-6 antibody and dominant negative STAT3β reduces chemoresistance and inhibits invasion of EBERs-expressing gastric cancer cells. Our results thus revealed a novel role of EBERs in the coordination of IL-6-STAT3 signaling pathway to chemoresistance and cellular migration.

The Primate EAE Model Points at EBV-Infected B Cells as a Preferential Therapy Target in Multiple Sclerosis

The remarkable clinical efficacy of anti-CD20 monoclonal antibodies (mAb) in relapsing-remitting multiple sclerosis points at the critical involvement of B cells in the disease. However, the exact pathogenic contribution of B cells is poorly understood. In this publication we review new data on the role of CD20+ B cells in a unique experimental autoimmune encephalomyelitis (EAE) model in common marmosets (Callithrix jacchus), a small-bodied neotropical primate. We will also discuss the relevance of these data for MS. Different from rodent EAE models, but similar to MS, disease progression in marmosets can develop independent of autoantibodies. Progressive disease is mediated by MHC class Ib (Caja-E) restricted cytotoxic T cells, which are activated by γ-herpesvirus-infected B cells and cause widespread demyelination of cortical gray matter. B-cell directed monoclonal antibody therapies (anti-CD20 versus anti-BLyS and anti-APRIL) have a variable effect on EAE progression, which we found associated with variable depletion of the Epstein Barr virus (EBV)-like γ-herpesvirus CalHV3 from lymphoid organs. These findings support an important pathogenic role of CD20+ B cell in MS, especially of the subset infected with EBV.

HLA-E expression by gynecological cancers restrains tumor-infiltrating CD8⁺ T lymphocytes

HLA-E is a nonclassical HLA class I molecule, which differs from classical HLA molecules by its nonpolymorphic, conserved nature. Expression and function of HLA-E in normal tissues and solid tumors is not fully understood. We investigated HLA-E protein expression on tissue sections of 420 ovarian and cervical cancers and found equal or higher levels than normal counterpart epithelia in 80% of the tumors. Expression was strongly associated with components of the antigen presentation pathway, e.g., transporter associated with antigen processing (TAP), endoplasmic reticulum aminopeptide (ERAP), β2 microglobulin (β2m), HLA classes I and II, and for ovarian cancer with tumor infiltrating CD8(+) T lymphocytes (CTLs). This association argues against the idea that HLA-E would compensate for the loss of classical HLA in tumors. In situ detection of HLA-E interacting receptors revealed a very low infiltrate of natural killer (NK) cells, but up to 50% of intraepithelial CTLs expressed the inhibiting CD94/NKG2A receptor. In cervical cancer, HLA-E expression did not alter the prognostic effect of CTLs, most likely due to very high infiltrating CTL numbers in this virus-induced tumor. Overall survival of ovarian cancer patients, however, was strongly influenced by HLA-E, because the beneficial effect of high CTL infiltration was completely neutralized in the subpopulation with strong HLA-E expression. Interestingly, these results indicate that CTL infiltration in ovarian cancer is associated with better survival only when HLA-E expression is low and that intratumoral CTLs are inhibited by CD94/NKG2A receptors on CTLs in the tumor microenvironment.

Immune manipulation of advanced breast cancer: an interpretative model of the relationship between immune system and tumor cell biology

This review summarizes some recent clinical immunological approaches with cytokines and/or antibodies for therapy of advanced breast cancer. It considers the recent advances in genetics and molecular tumor biology related to impaired immunosurveillance involving cytokines and growth factors to explain clinical results. Evasion of the host immune attack might be induced by the following groups of mechanisms: (a) tumor dependent (genomic instability, HLA class I antigen abnormalities, upregulation of fetal type nonclassical HLA class I molecules, epitope immunodominance, apoptosis inhibition by defective death receptor signaling, apoptosis of activated T cells, tumor cannibalism and constitutive activation of signal transducer, and activator of transcription-3 (Stat 3) and nuclear factor-kappaB (NF-kappaB) signaling); (b) host dependent (CD4+CD25+ regulatory T cells (T reg), CD4+ T cells anergy, Th2 antitumor immunity diversion and myeloid suppressor cells); (c) tumor and host dependent (lack of co-stimulation molecules, immunosuppressive cytokines (vascular endothelial growth factor (VEGF), interleukin (IL)-10, prostaglandin (PG)E2, transforming growth factor (TGF)-beta)). Cytokines and growth factors are involved in virtually all three types of mechanisms. These mechanisms are integrated with the current knowledge of tumor growth and inhibited apoptosis primarily mediated by cytokines and growth factors to propose an interpretation of the relationships among tumor cells, tumor stroma, and tumor-infiltrating lymphocytes. Tumor growth, defective immunorecognition and immunosuppression are the three principal effects considered responsible for immune evasion.

Genetic variation of antigen processing machinery components and association with cervical carcinoma

The antigen processing machinery (APM) plays an important role in immune recognition of virally infected and transformed cells. Defective expression of several APM components is associated with progression and clinical outcome in cervical carcinoma. Genetic variation in the genes encoding APM components is known to be associated with risk of occurrence of several malignancies. However, only limited evidence exists supporting the role of single nucleotide polymorphisms (SNPs) in APM components in cervical carcinoma. We have therefore investigated the occurrence of APM component SNP genotypes and haplotypes in cervical carcinoma. Thirteen coding SNPs in the LMP2, LMP7, TAP1, TAP2, and ERAP1 genes were genotyped in 127 cervical carcinoma patients and 124 controls. Individual genotype and allele distributions were assessed by single-marker analysis. Effects of various SNP combinations were estimated by haplotype construction and subsequent haplotype interaction analysis. Significant haplotypes were modeled on disease risk. Allele distributions at the LMP7-145, TAP2-651, ERAP1-127, and ERAP1-730 loci differed significantly between cases and controls with the major allele at the LMP7 and TAP2 loci and the minor allele at both ERAP1 loci associated with increased cervical carcinoma risk. A combination of the two haplotypes spanning these loci was associated with a three-fold increased risk (OR = 3.024; P << 0.001); approximately 12% of all cervical carcinoma occurrences were attributable to this combination. Our data indicate that combined genetic variation in the TAP2, LMP7, and ERAP1 genes is associated with increased cervical carcinoma risk.

Interferon-mediated immunopathological events are associated with atypical innate and adaptive immune responses in patients with severe acute respiratory syndrome

It is not understood how immune inflammation influences the pathogenesis of severe acute respiratory syndrome (SARS). One area of strong controversy is the role of interferon (IFN) responses in the natural history of SARS. The fact that the majority of SARS patients recover after relatively moderate illness suggests that the prevailing notion of deficient type I IFN-mediated immunity, with hypercytokinemia driving a poor clinical course, is oversimplified. We used proteomic and genomic technology to systematically analyze host innate and adaptive immune responses of 40 clinically well-described patients with SARS during discrete phases of illness from the onset of symptoms to discharge or a fatal outcome. A novel signature of high IFN-alpha, IFN-gamma, and IFN-stimulated chemokine levels, plus robust antiviral IFN-stimulated gene (ISG) expression, accompanied early SARS sequelae. As acute illness progressed, SARS patients entered a crisis phase linked to oxygen saturation profiles. The majority of SARS patients resolved IFN responses at crisis and expressed adaptive immune genes. In contrast, patients with poor outcomes showed deviated ISG and immunoglobulin gene expression levels, persistent chemokine levels, and deficient anti-SARS spike antibody production. We contend that unregulated IFN responses during acute-phase SARS may culminate in a malfunction of the switch from innate immunity to adaptive immunity. The potential for the use of the gene signatures we describe in this study to better assess the immunopathology and clinical management of severe viral infections, such as SARS and avian influenza (H5N1), is therefore worth careful examination.

Upregulation of antigen-processing machinery components at mRNA level in acute lymphoblastic leukemia cells after CD40 stimulation

The development of immunotherapy in hematologic malignancies has been observed in the last few years. One of the approaches is the use of cancer vaccines based on leukemia-derived dendritic cells (DC). Recent studies from our laboratory and other laboratories have shown that CD40 stimulation improves leukemia cells immunogenicity and generates an antitumor immune response. The design of future cancer vaccines requires the knowledge concerning the function of dendritic cells including antigen processing. The aim of our present study was the assessment of antigen-processing machinery (APM) components in acute lymphoblastic leukemia (ALL) cells before and after CD40 stimulation at messenger RNA (mRNA) level. Twenty-five children with ALL were enrolled into the study. Leukemic cells were stimulated (or not) with CD40L and IL-4. Elements of the antigen-processing machinery (MB1, LMP2, LMP7, LMP10, TAP1, TAP2, calnexin, calreticulin, tapasin, ERp57, zeta, delta) were determined by real-time PCR technique. The expression of important costimulatory and adhesion molecules considered as DC markers (CD40, CD54, CD80, CD83, CD86) were determined at the mRNA (PCR) and protein (flow cytometry) levels. The following are the results of our study: (1) We noted an upregulation of all costimulatory and adhesion molecules at the mRNA and protein levels in ALL cells after the culture; (2) the significant rise in expression of nearly all APM components after CD40 stimulation was observed. This confirms specific stimulation of the antigen-processing system in ALL cells by CD40L. Future work should focus on the clinical significance of these findings for immunotherapy in leukemias.