Border Control: The Role of the Microbiome in Regulating Epithelial Barrier Function

The gut mucosal epithelium is one of the largest organs in the body and plays a critical role in regulating the crosstalk between the resident microbiome and the host. To this effect, the tight control of what is permitted through this barrier is of high importance. There should be restricted passage of harmful microorganisms and antigens while at the same time allowing the absorption of nutrients and water. An increased gut permeability, or "leaky gut", has been associated with a variety of diseases ranging from infections, metabolic diseases, and inflammatory and autoimmune diseases to neurological conditions. Several factors can affect gut permeability, including cytokines, dietary components, and the gut microbiome. Here, we discuss how the gut microbiome impacts the permeability of the gut epithelial barrier and how this can be harnessed for therapeutic purposes.

Age-induced changes in anti-tumor immunity alter the tumor immune infiltrate and impact response to immuno-oncology treatments

Introduction

Immuno-oncology (IO) research relies heavily on murine syngeneic tumor models. However, whilst the average age for a cancer diagnosis is 60 years or older, for practical purposes the majority of preclinical studies are conducted in young mice, despite the fact that ageing has been shown to have a significant impact on the immune response.

Methods

Using aged (60-72 weeks old) mice bearing CT26 tumors, we investigated the impact of ageing on tumor growth as well as the immune composition of the tumor and peripheral lymphoid organs.

Results

We found many differences in the immune cell composition of both the tumor and tumor-draining lymph node between aged and young mice, such as a reduction in the naïve T cell population and a decreased intratumoral CD8/Treg ratio in aged animals. We hypothesized that these differences may contribute to impaired anti-cancer immune responses in aged mice and therefore assessed the anti-tumor efficacy of different IO therapies in aged mice, including both co-stimulation (using an anti-OX40 antibody) and immune checkpoint blockade (using anti-PD-L1 and anti-CTLA-4 antibodies). Whilst aged mice retained the capacity to generate anti-tumor immune responses, these were significantly attenuated when compared to the responses observed in young mice.

Discussion

These differences highlight the importance of age-related immunological changes in assessing and refining the translational insights gained from preclinical mouse models.

The heightened importance of the microbiome in cancer immunotherapy

The human microbiome is recognized as a key factor in health and disease. This has been further corroborated by identifying changes in microbiome composition and function as a novel hallmark in cancer. These effects are exerted through microbiome interactions with host cells, impacting a wide variety of developmental and physiological processes. In this review, we discuss some of the latest findings on how the bacterial component of the microbiome can influence outcomes for different cancer immunotherapy modalities, highlighting identified mechanisms of action. We also address the clinical efforts to utilize this knowledge to achieve better responses to immunotherapy. A refined understanding of microbiome variations in patients and microbiome-host interactions with cancer therapies is essential to realize optimal clinical responses.

Deep phenotyping of surface stimulatory and inhibitory co-receptors on cancer-resident T and NK cells reveals cell subsets within the tumor-reactive CTL population that are uniquely defined by NKG2A expression

The field of Immuno-Oncology (IO) is evolving to utilise novel antibody backbones that can co-target multiple cell-surface stimulatory and inhibitory co-receptors (SICR). This approach necessitates a better understanding of SICR co-expression at the single-cell level on IO-relevant tumor-infiltrating leukocyte (TIL) cell types such as T and natural killer (NK) cells. Using high-dimensional flow cytometry we established a comprehensive SICR profile for tumor-resident T and NK cells across a range of human solid tumors where there is a clear need for improved immunotherapeutic intervention. Leveraging the power of our large flow panel, we performed deep-phenotyping of the critical CD8⁺CD39⁺ Cytotoxic T Lymphocyte (CTL) population that is enriched for tumor-reactive cytotoxic cells, revealing subsets that are differentiated by their SICR profile, including three that are uniquely defined by NKG2A expression. This study establishes a comprehensive SICR phenotype for human TIL T and NK cells, providing insights to guide the design and application of the next generation of IO molecules.

The MITRE trial protocol: a study to evaluate the microbiome as a biomarker of efficacy and toxicity in cancer patients receiving immune checkpoint inhibitor therapy

BACKGROUND

The gut microbiome is implicated as a marker of response to  immune checkpoint inhibitors (ICI) based on preclinical mouse models and preliminary observations in limited patient series. Furthermore, early studies suggest faecal microbial transfer may have therapeutic potential, converting ICI non-responders into responders. So far, identification of specific responsible bacterial taxa has been inconsistent, which limits future application. The MITRE study will explore and validate a microbiome signature in a larger scale prospective study across several different cancer types.

METHODS

Melanoma, renal cancer and non-small cell lung cancer patients who are planned to receive standard immune checkpoint inhibitors are being recruited to the MITRE study. Longitudinal stool samples are collected prior to treatment, then at 6 weeks, 3, 6 and 12 months during treatment, or at disease progression/recurrence (whichever is sooner), as well as after a severe (≥grade 3 CTCAE v5.0) immune-related adverse event. Additionally, whole blood, plasma, buffy coat, RNA and peripheral blood mononuclear cells (PBMCs) is collected at similar time points and will be used for exploratory analyses. Archival tumour tissue, tumour biopsies at progression/relapse, as well as any biopsies from body organs collected after a severe toxicity are collected. The primary outcome measure is the ability of the microbiome signature to predict 1 year progression-free survival (PFS) in patients with advanced disease. Secondary outcomes include microbiome correlations with toxicity and other efficacy end-points. Biosamples will be used to explore immunological and genomic correlates. A sub-study will evaluate both COVID-19 antigen and antibody associations with the microbiome.

DISCUSSION

There is an urgent need to identify biomarkers that are predictive of treatment response, resistance and toxicity to immunotherapy. The data generated from this study will both help inform patient selection for these drugs and provide information that may allow therapeutic manipulation of the microbiome to improve future patient outcomes.

TRIAL REGISTRATION

NCT04107168 , ClinicalTrials.gov, registered 09/27/2019. Protocol V3.2 (16/04/2021).

Colloidal structure and proton conductivity of the gel within the electrosensory organs of cartilaginous fishes

Cartilaginous fishes possess gel-filled tubular sensory organs called Ampullae of Lorenzini (AoL) that are used to detect electric fields. Although recent studies have identified various components of AoL gel, it has remained unclear how the molecules are structurally arranged and how their structure influences the function of the organs. Here we describe the structure of AoL gel by microscopy and small-angle X-ray scattering and infer that the material is colloidal in nature. To assess the relative function of the gel's protein constituents, we compared the microscopic structure, X-ray scattering, and proton conductivity properties of the gel before and after enzymatic digestion with a protease. We discovered that while proteins were largely responsible for conferring the viscous nature of the gel, their removal did not diminish proton conductivity. The findings lay the groundwork for more detailed studies into the specific interactions of molecules inside AoL gel at the nanoscale.

Abstract 1783: Precision microbiome profiling identifies a novel biomarker predictive of Immune Checkpoint Inhibitor response in multiple cohorts and a potent therapeutic consortium of bacteria

Four independent international groups have demonstrated that the pre-treatment gut microbiome of cancer patients is associated with the subsequent response to treatment with Immune Checkpoint Inhibitors (ICI) [1-4]. However, each study identified different bacteria as being linked to outcome, which has limited the development of drug response biomarkers and novel microbiome-based therapeutics. Here we describe the identification of a microbial signature predictive of response to ICI across multiple melanoma studies, and a derived Live Bacterial Therapeutic with potent anti-tumour activity. MELRESIST is a single centre, prospective melanoma patient data and biosample collection research study. We collected longitudinal stool samples from 69 patients with advanced melanoma who received standard anti-PD-1+/- anti-CTLA-4 antibodies. Shotgun metagenomic sequencing analysis of the baseline stool microbiome was done using Microbiotica's platform, which comprises the world's leading Reference Genome Database to give the most comprehensive and precise mapping of gut microbiomes. Using 6 months progression-free survival as our cut-off for response, the analysis revealed a small but discrete microbiome signature that differentiated responders and non-responders with an accuracy of 93%. We extended this signature by reanalysing another 3 melanoma patient stool sample sequence datasets [1-3] using the Microbiotica platform, and a machine learning-based bioinformatic model. The resultant bacterial signature accurately predicted response when all 4 studies when combined (91%), as well as when the cohorts were analysed individually (82-100%). We validated the model using independent cohorts and the signature using NSCLC and Renal Cell Carcinoma (RCC) datasets [4]. The latter indicated the bacteria associated with response may differ slightly between indications. At the core of the signature was 9 bacteria that were all overrepresented in patients that responded to ICI treatment. Notably as a consortium, these 9 bacteria demonstrated tumor growth inhibition when dosed in a syngeneic mouse model. These strains also stimulate primary immune cells in vitro leading to tumor cell killing. In summary, we have identified a microbiome biomarker that is predictive of response to ICI treatment in multiple clinical studies from different countries. In addition, a unique set of bacteria derived from the signature has great therapeutic potential in combination with ICIs.

References 1 Matson V et al Science (2018) 359:104 2 Gopalakrishnan V Science (2018) 359:97 3 Frankel AE et al Neoplasia (2017) 19:848 4 Routy B et al Science (2018) 359:91

Citation Format: Matthew J. Robinson, Kevin Vervier, Simon Harris, Roy Rabbie, Doreen Milne, Catherine Booth, Christine Parkinson, Sarah J. Welsh, David Bruce, Emily Barker, David Adams, Pippa Corrie, Trevor D. Lawley. Precision microbiome profiling identifies a novel biomarker predictive of Immune Checkpoint Inhibitor response in multiple cohorts and a potent therapeutic consortium of bacteria [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1783.

Abstract 2768: A novel non-terminal tumor sampling procedure using fine needle aspiration supports biomarker discovery

Immunotherapy is part of the standard of care for oncology however, durable objective responses remain limited to a subset of patients. As such there is a crucial need to identify biomarkers that can predict/enrich for treatment response. So far, the majority of proposed biomarkers consist of features of the tumor microenvironment (TME). However, in preclinical mouse models, the collection of tumor tissue for this type of analysis is a terminal procedure obviating the ability to directly link potential biomarkers to response/outcome following treatment. Therefore, we have developed and validated a novel non-terminal tumor sampling method to biopsy the TME in mouse models based on fine needle aspiration. We show that this technique enables repeated in-life sampling of subcutaneous flank tumors without impacting tumor growth or animal welfare. This method yields sufficient sample for flow cytometric analysis of tumor-infiltrating immune cells and we demonstrate that it is able to recapitulate results obtained with the current methodology of whole tumor analysis. We propose that this method represents a simple, fast, minimally invasive technique to enable analysis of the TME, reduction in the number of animals used for preclinical oncology studies and refinement of pharmacodynamic analysis. Additionally, its unique ability to provide longitudinal TME sampling can support investigation of biomarkers of response to treatment.

Citation Format: Suzanne I. Sitnikova, Sophie Munnings-Tomes, Stacy R. Kentner, Kathy Mulgrew, Judit Espana-Agusti, Tianhui Zhang, Kristina M. Ilieva, Hormas M. Ghadially, Matthew J. Robinson, Robert W. Wilkinson, Simon J. Dovedi. A novel non-terminal tumor sampling procedure using fine needle aspiration supports biomarker discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2768.

Novel non-terminal tumor sampling procedure using fine needle aspiration supports immuno-oncology biomarker discovery in preclinical mouse models

Background

Immuno-oncology therapies are now part of the standard of care for cancer in many indications. However, durable objective responses remain limited to a subset of patients. As such, there is a critical need to identify biomarkers that can predict or enrich for treatment response. So far, the majority of putative biomarkers consist of features of the tumor microenvironment (TME). However, in preclinical mouse models, the collection of tumor tissue for this type of analysis is a terminal procedure, obviating the ability to directly link potential biomarkers to long-term treatment outcomes.

Methods

To address this, we developed and validated a novel non-terminal tumor sampling method to enable biopsy of the TME in mouse models based on fine needle aspiration.

Results

We show that this technique enables repeated in-life sampling of subcutaneous flank tumors and yields sufficient material to support downstream analyses of tumor-infiltrating immune cells using methods such as flow cytometry and single-cell transcriptomics. Moreover, using this technique we demonstrate that we can link TME biomarkers to treatment response outcomes, which is not possible using the current method of terminal tumor sampling.

Conclusion

Thus, this minimally invasive technique is an important refinement for the pharmacodynamic analysis of the TME facilitating paired evaluation of treatment response biomarkers with outcomes and reducing the number of animals used in preclinical research.

Defective bacterial phagocytosis is associated with dysfunctional mitochondria in COPD macrophages

Increased reactive oxygen species (ROS) have been implicated in the pathophysiology of chronic obstructive pulmonary disease (COPD). This study examined the effect of exogenous and endogenous oxidative stress on macrophage phagocytosis in patients with COPD.Monocyte-derived macrophages (MDMs) were generated from non-smoker, smoker and COPD subjects, differentiated in either granulocyte macrophage-colony stimulating factor (G-Mφ) or macrophage-colony stimulating factor (M-Mφ). Alveolar macrophages were isolated from lung tissue or bronchoalveolar lavage fluid. Macrophages were incubated in ±200 µM H₂O₂ for 24 h, then exposed to fluorescently labelled Haemophilus influenzae or Streptococcus pneumoniae for 4 h, after which phagocytosis, mitochondrial ROS (mROS) and mitochondrial membrane potential (ΔΨm) were measured.Phagocytosis of bacteria was significantly decreased in both G-Mφ and M-Mφ from COPD patients compared with from non-smoker controls. In non-smokers and smokers, bacterial phagocytosis did not alter mROS or ΔΨm; however, in COPD, phagocytosis increased early mROS and decreased ΔΨm in both G-Mφ and M-Mφ. Exogenous oxidative stress reduced phagocytosis in non-smoker and COPD alveolar macrophages and non-smoker MDMs, associated with reduced mROS production.COPD macrophages show defective phagocytosis, which is associated with altered mitochondrial function and an inability to regulate mROS production. Targeting mitochondrial dysfunction may restore the phagocytic defect in COPD.

Abstract 4987: Age-induced changes in anti-tumor immunity alter the tumor immune infiltrate and reduce response to immuno-oncology treatments

Immuno-oncology research relies heavily on murine syngeneic tumor models. However, whilst the median age for a cancer diagnosis is 65 years or older, for practical purposes the majority of preclinical studies are conducted in young mice, despite the fact that aging has been shown to have a significant impact on the immune response. Using aged mice bearing CT26 tumors, we analysed how aging impacts the immune composition of the tumor, spleen and tumor-draining lymph nodes by flow cytometry. We found many age-related changes between aged (60-72 weeks old) and young (6-8 weeks old) mice, such as a reduction in the naïve T cell population and a decreased CD8/Treg ratio in aged animals. Profiling of co-inhibitory and co-stimulatory receptor expression levels on immune cells in aged versus young mice also identified altered expression profiles in both the periphery and tumor. We hypothesised that these differences may contribute to impaired anti-cancer immune responses in aged mice. To investigate this, we compared the anti-tumor efficacy of immune checkpoint blockade (PD-L1 and CTLA-4) and T-cell costimulation (OX-40) in aged versus young mice. Our data demonstrate that aged mice retained their capacity to generate effective anti-tumor immune responses, albeit often attenuated when compared to the responses observed in young mice. These differences highlight the potential importance of age-related immunological changes in assessing and refining the translational insights gained from preclinical mouse models.

Citation Format: Suzanne I. Sitnikova, Michelle Morrow, Viia Valge-Archer, Robert W. Wilkinson, Simon J. Dovedi, Matthew J. Robinson. Age-induced changes in anti-tumor immunity alter the tumor immune infiltrate and reduce response to immuno-oncology treatments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4987.

Microbiota Sensing by Mincle-Syk Axis in Dendritic Cells Regulates Interleukin-17 and -22 Production and Promotes Intestinal Barrier Integrity

Production of interleukin-17 (IL-17) and IL-22 by T helper 17 (Th17) cells and group 3 innate lymphoid cells (ILC3s) in response to the gut microbiota ensures maintenance of intestinal barrier function. Here, we examined the mechanisms whereby the immune system detects microbiota in the steady state. A Syk-kinase-coupled signaling pathway in dendritic cells (DCs) was critical for commensal-dependent production of IL-17 and IL-22 by CD4+ T cells. The Syk-coupled C-type lectin receptor Mincle detected mucosal-resident commensals in the Peyer's patches (PPs), triggered IL-6 and IL-23p19 expression, and thereby regulated function of intestinal Th17- and IL-17-secreting ILCs. Mice deficient in Mincle or with selective depletion of Syk in CD11c+ cells had impaired production of intestinal RegIIIγ and IgA and increased systemic translocation of gut microbiota. Consequently, Mincle deficiency led to liver inflammation and deregulated lipid metabolism. Thus, sensing of commensals by Mincle and Syk signaling in CD11c+ cells reinforces intestinal immune barrier and promotes host-microbiota mutualism, preventing systemic inflammation.

Haplosaurus computes protein haplotypes for use in precision drug design

Selecting the most appropriate protein sequences is critical for precision drug design. Here we describe Haplosaurus, a bioinformatic tool for computation of protein haplotypes. Haplosaurus computes protein haplotypes from pre-existing chromosomally-phased genomic variation data. Integration into the Ensembl resource provides rapid and detailed protein haplotypes retrieval. Using Haplosaurus, we build a database of unique protein haplotypes from the 1000 Genomes dataset reflecting real-world protein sequence variability and their prevalence. For one in seven genes, their most common protein haplotype differs from the reference sequence and a similar number differs on their most common haplotype between human populations. Three case studies show how knowledge of the range of commonly encountered protein forms predicted in populations leads to insights into therapeutic efficacy. Haplosaurus and its associated database is expected to find broad applications in many disciplines using protein sequences and particularly impactful for therapeutics design.

Abstract 3765: An anti-CD137 antibody can show greater efficacy in syngeneic mouse tumor models when combined with other immuno-oncology (IO) therapies

CD137 is a costimulatory molecule associated with tumour infiltrating lymphocytes and cytotoxic T lymphocytes in particular. Murine anti-CD137 monoclonal antibodies (mAbs) have shown potent anti-tumour effects in syngeneic tumour models, which can be further enhanced by combination with checkpoint inhibitor (CPI) mAbs to PD-1, or CTLA-4 and OX40. Two anti-CD137 monoclonal antibodies (mAbs), Urelumab and Utomilumab, are in development for both haematological and solid cancers, and studies include combinations with other IO therapies such as anti-PD-1, anti-PD-L1 and anti-OX40 mabs. We studied the impact of combining anti-CD137 with CPIs anti-PD-L1, anti-CTLA4, and IO agonist GITRL fusion protein (GITRL-FP) and anti-OX40 on pharmacodynamic responses, tumour growth and survival in mouse syngeneic models. In a responsive model, CT26, combining anti-CD137 with anti-PD-L1 had a greater impact on tumour growth inhibition, which correlated with an enhanced proliferation of CD8 T cells, as determined Ki67 expression using flow cytometry. In MC-38, a model that is less sensitive to both monotherapies, the combination was synergistic and resulted in enhanced tumour growth inhibition. Next, we compared the anti-CTLA4, anti-OX40 and GITRL-FP as monotherapies and in combination with anti-CD137 in the CT26 model. As before, anti-CD137 alone induced CD8 T cell proliferation, whereas anti-OX40 and GITRL-FP stimulated expansion of CD8 and CD4 T cells. Interestingly, in all combinations anti-CD137 appeared to enhance both CD8 and CD4 T cell proliferation. Anti-CTLA4 and GITR-FP had a greater impact on tumour growth inhibition when combined with anti-CD137. In summary, in vivo models indicate that anti-CD137 mAbs are a promising therapy in cancer, but the most benefit may be obtained in combination with other IO therapies.

Citation Format: Matthew J. Robinson, Ines Osma-Garcia, Jane Coates-Ulrichisen, Amanda Watkins, Suzanne Mosely, Chrisopher Lloyd, Geoff Williams, Michelle Morrow, Simon Dovedi, Ronald Herbst, Robert Wilkinson. An anti-CD137 antibody can show greater efficacy in syngeneic mouse tumor models when combined with other immuno-oncology (IO) therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3765.

The bismuth oxyhalide family: thin film synthesis and periodic properties

The complete bismuth oxyhalides were synthesized as thin films. β-Bi₂O₃ films were transformed into BiOX for X = F, Cl and Br by chemical baths; BiOI was obtained by spraying the solution directly. All BiOX films present photocatalytic activity under simulated sunlight.

Granulocyte macrophage colony-stimulating factor receptor α expression and its targeting in antigen-induced arthritis and inflammation

Background

Blockade of granulocyte macrophage colony-stimulating factor (GM-CSF) and its receptor (GM-CSFRα) is being successfully tested in trials in rheumatoid arthritis (RA) with clinical results equivalent to those found with neutralization of the current therapeutic targets, TNF and IL-6. To explore further the role of GM-CSF as a pro-inflammatory cytokine, we examined the effect of anti-GM-CSFRα neutralization on myeloid cell populations in antigen-driven arthritis and inflammation models and also compared its effect with that of anti-TNF and anti-IL-6.

Methods

Cell population changes upon neutralization by monoclonal antibodies (mAbs) in the antigen-induced arthritis (AIA) and antigen-induced peritonitis (AIP) models were monitored by flow cytometry and microarray. Adoptive transfer of monocytes into the AIP cavity was used to assess the GM-CSF dependence of the development of macrophages and monocyte-derived dendritic cells (Mo-DCs) at a site of inflammation.

Results

Therapeutic administration of a neutralizing anti-GM-CSF mAb, but not of an anti-colony-stimulating factor (anti-CSF)-1 or an anti-CSF-1R mAb, ameliorated AIA disease. Using the anti-GM-CSFRα mAb, the relative surface expression of different inflammatory myeloid populations was found to be similar in the inflamed tissues in both the AIA and AIP models; however, the GM-CSFRα mAb, but not neutralizing anti-TNF and anti-IL-6 mAbs, preferentially depleted Mo-DCs from these sites. In addition, we were able to show that locally acting GM-CSF upregulated macrophage/Mo-DC numbers via GM-CSFR signalling in donor monocytes.

Conclusions

Our findings suggest that GM-CSF blockade modulates inflammatory responses differently to TNF and IL-6 blockade and may provide additional insight into how targeting the GM-CSF/GM-CSFRα system is providing efficacy in RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1185-9) contains supplementary material, which is available to authorized users.

Pulmonary pharmacodynamics of an anti-GM-CSFRα antibody enables therapeutic dosing that limits exposure in the lung

Pulmonary alveolar proteinosis is associated with impaired alveolar macrophage differentiation due to genetic defects in the granulocyte macrophage colony-stimulating factor (GM-CSF) axis or autoantibody blockade of GM-CSF. The anti-GM-CSFRα antibody mavrilimumab has shown clinical benefit in patients with rheumatoid arthritis, but with no accompanying pulmonary pathology observed to date. We aimed to model systemic versus pulmonary pharmacodynamics of an anti-GM-CSFRα antibody to understand the pharmacology that contributes to this therapeutic margin. Mice were dosed intraperitoneal with anti-GM-CSFRα antibody, and pharmacodynamics bioassays for GM-CSFRα inhibition performed on blood and bronchoalveolar lavage (BAL) cells to quantify coverage in the circulation and lung, respectively. A single dose of 3 mg/kg of the anti-GM-CSFRα antibody saturated the systemic cellular pool, but dosing up to 10 times higher had no effect on the responsiveness of BAL cells to GM-CSF. Continued administration of this dose of anti-GM-CSFRα antibody for 7 consecutive days also had no inhibitory effect on these cells. Partial inhibition of GM-CSFRα function on cells from the BAL was only observed after dosing for 5 or 7 consecutive days at 30 mg/kg, 10-fold higher than the proposed therapeutic dose. In conclusion, dosing with anti-GM-CSFRα antibody using regimes that saturate circulating cells, and have been shown to be efficacious in inflammatory arthritis models, did not lead to complete blockade of the alveolar macrophages response to GM-CSF. This suggests a significant therapeutic window is possible with GM-CSF axis inhibition.

Generation of potent mouse monoclonal antibodies to self-proteins using T-cell epitope "tags"

Immunization of mice or rats with a "non-self" protein is a commonly used method to obtain monoclonal antibodies, and relies on the immune system's ability to recognize the immunogen as foreign. Immunization of an antigen with 100% identity to the endogenous protein, however, will not elicit a robust immune response. To develop antibodies to mouse proteins, we focused on the potential for breaking such immune tolerance by genetically fusing two independent T-cell epitope-containing sequences (from tetanus toxin (TT) and diphtheria toxin fragment A (DTA)) to a mouse protein, mouse ST2 (mST2). Wild-type CD1 mice were immunized with three mST2 tagged proteins (Fc, TT and DTA) and the specific serum response was determined. Only in mice immunized with the T-cell epitope-containing antigens were specific mST2 serum responses detected; hybridomas generated from these mice secreted highly sequence-diverse IgGs that were capable of binding mST2 and inhibiting the interaction of mST2 with its ligand, mouse interleukin (IL)-33 (mIL-33). Of the hundreds of antibodies profiled, we identified five potent antibodies that were able to inhibit IL-33 induced IL-6 release in a mast cell assay; notably one such antibody was sufficiently potent to suppress IL-5 release and eosinophilia infiltration in an Alternaria alternata challenge mouse model of asthma. This study demonstrated, for the first time, that T-cell epitope-containing tags have the ability to break tolerance in wild-type mice to 100% conserved proteins, and it provides a compelling argument for the broader use of this approach to generate antibodies against any mouse protein or conserved ortholog.

The effect of level of crude protein and available lysine on finishing pig performance, nitrogen balance and nutrient digestibility

Two trials were conducted to investigate the effect of decreasing the crude protein (CP) content of diets for finishing pigs containing two levels of available lysine on nutrient digestibility, nitrogen (N) balance and production performance. Ten finishing diets containing five levels of CP (on average 144, 155, 168, 182 and 193 g/kg fresh basis) and two levels of available lysine (6.9 and 8.2 g/kg fresh basis) were formulated. The diets were offered to pigs on a performance trial (n = 800 Large White (LW)×Landrace (LR) pigs) from 10 wk of age until finish at 21 wks+5 d of age. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. In addition, a digestibility/N balance trial was conducted using pigs (n = 80 LW×LR) housed in metabolism crates. Digestibility of dry matter (DM), CP, oil, fibre and energy was determined. N balance values were determined through analysis of N content of urine and faeces (‘as determined’). N balance values were also calculated using ADG values and assuming that 16% of growth is protein deposition (“as calculated”). Pig performance was poor between 10 and 13 wk of age which indicated that the dietary treatments were nutritionally inadequate for pigs less than 40 kg. There was a significant (p<0.01) quadratic effect of increasing CP level on feed intake, ADG and FCR from 10 to 13 wk which indicated that the lower CP levels did not supply adequate levels of essential or non-essential amino acids. There was no effect of increasing available lysine level throughout the early period, which in conjunction with the response in older pigs, suggested that both 8.2 and 6.9 g/kg available lysine were insufficient to drive optimum growth. There was a positive response (p<0.05) to increasing available lysine level from 13 wk to finish which indicated that 6.9 g/kg available lysine was not adequate for finishing pigs. Energy digestibility decreased with decreasing CP level of diets containing 6.9 g/kg available lysine which may be attributed to the higher fibre content of the lower CP diets. Nitrogen excretion (g/d) was lowered when dietary CP was reduced regardless of whether the values were determined through balance or calculated using ADG. Calculated N excretion decreased linearly (p<0.001) and quadratically (p<0.001) with decreasing dietary CP content. When the N balance figures calculated in this study were compared with those quoted in the Northern Ireland and English Nitrates Directive Action Programmes, N excretion was less per pig (wean to finish) offered a 169 g/kg CP, 8.2 g/kg available lysine diet (2.39 kg vs 3.41 kg (Northern Ireland) and 2.93 kg (England)).

Dectin-2 sensing of house dust mite is critical for the initiation of airway inflammation

How the immune system senses aeroallergens and triggers an aberrant inflammation is poorly understood. Dectin-2 is a house dust mite (HDM)-sensing pattern recognition receptor. In a 3-week mouse model of repeated intranasal HDM challenge, anti-Dectin-2 potently attenuated the characteristic allergic inflammation and airway hyper-responsiveness. Anti-Dectin-2 also prevented neutrophil influx following a single HDM challenge. Interestingly, cysteinyl leukotrienes, but not chemokine and cytokine levels were inhibited by anti-Dectin-2 in this acute model, and in ex vivo challenge of cultured alveolar macrophages with HDM. Furthermore in the single-challenge model, zileuton, an inhibitor of leukotriene production, produced a similar effect as Dectin-2 blockade. Together these data suggest alveolar macrophage sensing of HDM by Dectin-2 elicits the production of cysteinyl leukotrienes, and this axis is key for the initiation of airway inflammation to this aeroallergen. Finally, we found Dectin-2-positive infiltrating cells present in bronchial biopsies from asthmatic subjects.

The rise and fall of XMRV

Due to the relatively recent emergence of the human T-lymphotropic and the human immunodeficiency viruses, enthusiasm for the identification of novel viruses, especially retroviruses, with pathogenic potential in humans, remains high. Novel technologies are now available with the ability to search for unknown viruses, such as gene arrays and new generation sequencing of tissue and other samples. In 2006, chip technology identified a novel retrovirus in human prostate cancer (PCa) tissue samples. Due to close homology to a mouse retrovirus, the virus was named xenotropic murine leukaemia virus-related virus (XMRV). Ever since the initial disease association with PCa, XMRV has stirred a lot of attention and concern worldwide for the medical community, public health officials and in particular global transfusion services. Public response, in this new era of electronic communication and advocacy was rapid, wide and unprecedented. In this review, we outline the course of biomedical research efforts that were put forward internationally in the process of determining the risk to the human population, the response of the blood banking community and review the current state of knowledge of xenotropic murine retroviruses. Although XMRV is no longer regarded as an infection of humans, a lesson was learnt in modern virology that holds deeper implications for biomedical research, particularly stem cell generation and transplantation practices.

Acute effects of an Avena sativa herb extract on responses to the Stroop Color-Word test

BACKGROUND AND AIMS

Extracts from oat (Avena sativa) herb may benefit cognitive performance. This study investigated whether Neuravena(®), an oat herb extract, could acutely improve responses to the Stroop Color-Word test, a measure of attention and concentration and the ability to maintain task focus.

SUBJECTS AND METHODS

Elderly volunteers with below-average cognitive performance consumed single doses (0, 1600, and 2400 mg) of oat herb extract at weekly intervals in a double-blind, randomized, crossover comparison. Resting blood pressure (BP) was assessed before and after supplementation, and a Stroop test was performed.

RESULTS

Significantly fewer errors were made during the color-naming component of the Stroop test after consuming the 1600-mg dose than after the 0-mg or 2400-mg doses (F (1,36)=18.85, p<0.001). In 7 subjects with suspected cognitive impairment, Stroop interference score was also improved by the 1600-mg dose compared to 0- and 2400-mg doses (F (1, 34)=2.40, p<0.01). Resting BP was unaffected by supplementation.

CONCLUSIONS

Taking 1600 mg of oat herb extract may acutely improve attention and concentration and the ability to maintain task focus in older adults with differing levels of cognitive status.

Hoxb8 conditionally immortalised macrophage lines model inflammatory monocytic cells with important similarity to dendritic cells

We have examined the potential to generate bona fide macrophages (MØ) from conditionally immortalised murine bone marrow precursors. MØ can be derived from Hoxb8 conditionally immortalised macrophage precursor cell lines (MØP) using either M-CSF or GM-CSF. When differentiated in GM-CSF (GM-MØP) the resultant cells resemble GM-CSF bone marrow-derived dendritic cells (BMDC) in morphological phenotype, antigen phenotype and functional responses to microbial stimuli. In spite of this high similarity between the two cell types and the ability of GM-MØP to effectively present antigen to a T-cell hybridoma, these cells are comparatively poor at priming the expansion of IFN-γ responses from naïve CD4(+) T cells. The generation of MØP from transgenic or genetically aberrant mice provides an excellent opportunity to study the inflammatory role of GM-MØP, and reduces the need for mouse colonies in many studies. Hence differentiation of conditionally immortalised MØPs in GM-CSF represents a unique in vitro model of inflammatory monocyte-like cells, with important differences from bone marrow-derived dendritic cells, which will facilitate functional studies relating to the many 'sub-phenotypes' of inflammatory monocytes.

Dectin-2 is a Syk-coupled pattern recognition receptor crucial for Th17 responses to fungal infection

Innate immune cells detect pathogens via pattern recognition receptors (PRRs), which signal for initiation of immune responses to infection. Studies with Dectin-1, a PRR for fungi, have defined a novel innate signaling pathway involving Syk kinase and the adaptor CARD9, which is critical for inducing Th17 responses to fungal infection. We show that another C-type lectin, Dectin-2, also signals via Syk and CARD9, and contributes to dendritic cell (DC) activation by fungal particles. Unlike Dectin-1, Dectin-2 couples to Syk indirectly, through association with the FcRγ chain. In a model of Candida albicans infection, blockade of Dectin-2 did not affect innate immune resistance but abrogated Candida-specific T cell production of IL-17 and, in combination with the absence of Dectin-1, decreased Th1 responses to the organism. Thus, Dectin-2 constitutes a major fungal PRR that can couple to the Syk–CARD9 innate signaling pathway to activate DCs and regulate adaptive immune responses to fungal infection.

Diagnosis of human metapneumovirus by immunofluorescence staining with monoclonal antibodies in the North-East of England

BACKGROUND

Since its discovery in 2001 human metapneumovirus (hMPV) has been shown to be a significant cause of human respiratory disease, responsible for 5-8% of respiratory infections in hospitalised children. Diagnosis hitherto has been largely carried out by reverse tanscriptase polymerase chain reaction (RT-PCR) but immunofluorescence staining of cells from nasopharyngeal secretions (IF) offers advantages for some laboratories and may produce a more rapid result in urgent cases. We have recently demonstrated that IF with a rabbit antiserum gave sensitivity equal to that of RT-PCR. However, monoclonal antibodies offer a more plentiful, uniform IF reagent.

OBJECTIVES

Here we have evaluated a pool of anti-hMPV monoclonal antibodies in the routine diagnosis of respiratory infections in hospitalised infants and children.

STUDY DESIGN

Eight hundred and fifty-seven routine respiratory specimens were tested by IF with rabbit polyclonal antiserum and monoclonal antibody pool in parallel. A further 1003 specimens were tested with the monoclonal antibody pool alone. All specimens were also tested for a panel of other respiratory viruses by IF.

RESULTS

Both rabbit polyclonal antiserum and monoclonal antibody pool gave positive results in 56 and negative results in 797 specimens. The rabbit polyclonal antibody detected virus in a further two specimens which were negative when tested with the monoclonal pool giving a concordance of 96.6% and a specificity of 100% for the monoclonal antibody pool. Overall hMPV was detected in 5% of specimens whilst 18.4% were positive for hRSV.

CONCLUSIONS

The monoclonal antibody pool-based IF is a robust assay suitable for routine use with a sensitivity only slightly less than that of the other major diagnostic methodologies available.

Syk-dependent ERK activation regulates IL-2 and IL-10 production by DC stimulated with zymosan

Zymosan is a particulate yeast preparation that elicits high levels of IL-2 and IL-10 from dendritic cells (DC) and engages multiple innate receptors, including the Syk-coupled receptor dectin-1 and the MyD88-coupled receptor TLR2. Here, we show that induction of IL-2 and IL-10 by zymosan requires activation of ERK MAP kinase in murine DC. Surprisingly, ERK activation in response to zymosan is completely blocked in Syk-deficient DC and unaffected by MyD88 deficiency. Conversely, ERK activation in response to the TLR2 agonist Pam3Cys is completely MyD88 dependent and unaffected by Syk deficiency. The inability of TLR2 ligands in zymosan to couple to ERK may explain the Syk dependence of the IL-2 and IL-10 response in DC and emphasises the importance of Syk-coupled pattern recognition receptors such as dectin-1 in the detection of yeasts. Furthermore, the lack of receptor compensation observed here suggests that responses induced by complex innate stimuli cannot always be predicted by the signalling pathways downstream of individual receptors.

Phosphorylation of TPL-2 on serine 400 is essential for lipopolysaccharide activation of extracellular signal-regulated kinase in macrophages

Tumor progression locus 2 (TPL-2) kinase is essential for Toll-like receptor 4 activation of the mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) and for upregulation of the inflammatory cytokine tumor necrosis factor (TNF) in lipopolysaccharide (LPS)-stimulated macrophages. LPS activation of ERK requires TPL-2 release from associated NF-kappaB1 p105, which blocks TPL-2 access to its substrate, the ERK kinase MEK. Here we demonstrate that TPL-2 activity is also regulated independently of p105, since LPS stimulation was still needed for TPL-2-dependent activation of ERK in Nfkb1(-/-) macrophages. In wild-type macrophages, LPS induced the rapid phosphorylation of serine (S) 400 in the TPL-2 C-terminal tail. Mutation of this conserved residue to alanine (A) blocked the ability of retrovirally expressed TPL-2 to induce the activation of ERK in LPS-stimulated Nfkb1(-/-) macrophages. TPL-2(S400A) expression also failed to reconstitute LPS activation of ERK and induction of TNF in Map3k8(-/-) macrophages, which lack endogenous TPL-2. Consistently, the S400A mutation was found to block LPS stimulation of TPL-2 MEK kinase activity. Thus, induction of TPL-2 MEK kinase activity by LPS stimulation of macrophages requires TPL-2 phosphorylation on S400, in addition to its release from NF-kappaB1 p105. Oncogenic C-terminal truncations of TPL-2 that remove S400 could promote its transforming potential by eliminating this critical control step.

Patterns of depressive symptom response in duloxetine-treated outpatients with mild, moderate or more severe depression

AIMS

This was a post hoc analysis to determine whether baseline severity of depression influenced the efficacy of duloxetine in treating major depressive disorder (MDD) and to better characterise the symptom response profile for duloxetine in patients with mild, moderate or more severe depression.

METHODS

Data were pooled from four double-blind, placebo-controlled studies in which outpatients with MDD were randomised to duloxetine (60 mg/day) or placebo for 8-9 weeks. Patients were retrospectively stratified according to baseline 17-item Hamilton Depression Rating scale (HAMD17) total scores: mild=total score<or=19 (duloxetine, n=246; placebo, n=184); moderate=20-24 (duloxetine, n=333; placebo, n=217); severe=25+ (duloxetine, n=127; placebo, n=87).

RESULTS

Duloxetine produced significantly greater baseline-to-end-point improvement vs. placebo (p<0.05) on the HAMD17 total score, Maier and retardation subscales, HAMD17 items 1 (depressed mood), 7 (work and activities) and 10 (psychic anxiety) in all three patient cohorts. The largest effect sizes were observed in assessments of core emotional depressive symptoms. A significant improvement for duloxetine vs. placebo was not observed for sleep-related symptoms at end-point or genital symptoms at any time point during acute treatment. With respect to the time course of depressive symptom improvement, the data show that regardless of baseline severity, the most rapid and consistent improvement for duloxetine compared with placebo was observed in the core symptoms of MDD (measured by the Maier subscale).

CONCLUSION

Regardless of baseline MDD severity, duloxetine at one dose (60 mg/day) produced a significant improvement compared with placebo on the core emotional symptoms of MDD.

Syk- and CARD9-dependent coupling of innate immunity to the induction of T helper cells that produce interleukin 17

The C-type lectin dectin-1 binds to yeast and signals through the kinase Syk and the adaptor CARD9 to induce production of interleukin 10 (IL-10) and IL-2 in dendritic cells (DCs). However, whether this pathway promotes full DC activation remains unclear. Here we show that dectin-1-Syk-CARD9 signaling induced DC maturation and the secretion of proinflammatory cytokines, including IL-6, tumor necrosis factor and IL-23, but little IL-12. Dectin-1-activated DCs 'instructed' the differentiation of CD4+ IL-17-producing effector T cells (T(H)-17 cells) in vitro, and a dectin-1 agonist acted as an adjuvant promoting the differentiation of T(H)-17 and T helper type 1 cells in vivo. Infection with Candida albicans induced CARD9-dependent T(H)-17 responses to the organism. Our data indicate that signaling through Syk and CARD9 can couple innate to adaptive immunity independently of Toll-like receptor signals and that CARD9 is required for the development of T(H)-17 responses to some pathogens.

Myeloid C-type lectins in innate immunity

C-type lectins expressed on myeloid cells comprise a family of proteins that share a common structural motif, and some act as receptors in pathogen recognition. But just as the presence of leucine-rich repeats alone is not sufficient to define a Toll-like receptor, the characterization of C-type lectin receptors in innate immunity requires the identification of accompanying signaling motifs. Here we focus on the known signaling pathways of myeloid C-type lectins and on their possible functions as autonomous activating or inhibitory receptors involved in innate responses to pathogens or self.

Lipopolysaccharide activation of the TPL-2/MEK/extracellular signal-regulated kinase mitogen-activated protein kinase cascade is regulated by IkappaB kinase-induced proteolysis of NF-kappaB1 p105

The MEK kinase TPL-2 (also known as Cot) is required for lipopolysaccharide (LPS) activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase cascade in macrophages and consequent upregulation of genes involved in innate immune responses. In resting cells, TPL-2 forms a stoichiometric complex with NF-kappaB1 p105, which negatively regulates its MEK kinase activity. Here, it is shown that lipopolysaccharide (LPS) stimulation of primary macrophages causes the release of both long and short forms of TPL-2 from p105 and that TPL-2 MEK kinase activity is restricted to this p105-free pool. Activation of TPL-2, MEK, and ERK by LPS is also demonstrated to require proteasome-mediated proteolysis. p105 is known to be proteolysed by the proteasome following stimulus-induced phosphorylation of two serines in its PEST region by the IkappaB kinase (IKK) complex. Expression of a p105 point mutant, which is not susceptible to signal-induced proteolysis, in RAW264.7 macrophages impairs LPS-induced release of TPL-2 from p105 and its subsequent activation of MEK. Furthermore, expression of wild-type but not mutant p105 reconstitutes LPS stimulation of MEK and ERK phosphorylation in primary NF-kappaB1-deficient macrophages. Consistently, pharmacological blockade of IKK inhibits LPS-induced release of TPL-2 from p105 and TPL-2 activation. These data show that IKK-induced p105 proteolysis is essential for LPS activation of TPL-2, thus revealing a novel function of IKK in the regulation of the ERK MAP kinase cascade.

Myeloid cell function in MRP-14 (S100A9) null mice

Myeloid-related protein 14 (MRP-14) and its heterodimeric partner, MRP-8, are cytosolic calcium-binding proteins, highly expressed in neutrophils and monocytes. To understand the function of MRP-14, we performed targeted disruption of the MRP-14 gene in mice. MRP-14(-/-) mice showed no obvious phenotype and were fertile. MRP-8 mRNA but not protein is present in the myeloid cells of these mice, suggesting that the stability of MRP-8 protein is dependent on MRP-14 expression. A compensatory increase in other proteins was not detected in cells lacking MRP-8 and MRP-14. Although the morphology of MRP-14(-/-) myeloid cells was not altered, they were significantly less dense. When Ca(2+) responses were investigated, there was no change in the maximal response to the chemokine MIP-2. At lower concentrations, however, there was reduced responsiveness in MRP-14(-/-) compared with MRP-14(+/+) neutrophils. This alteration in the ability to flux Ca(2+) did not impair the ability of the MRP-14(-/-) neutrophils to respond chemotactically to MIP-2. In addition, the myeloid cell functions of phagocytosis, superoxide burst, and apoptosis were unaffected in MRP-14(-/-) cells. In an in vivo model of peritonitis, MRP-14(-/-) mice showed no difference from wild-type mice in induced inflammatory response. The data indicate that MRP-14 and MRP-8 are dispensable for many myeloid cell functions.

Effect of a fourth Haemophilus influenzae type b immunisation in preterm infants who received dexamethasone for chronic lung disease

AIM

To assess whether a fourth Hib polysaccharide-tetanus protein conjugate vaccine (PRP-T) would improve antibody response in preterm infants previously treated with dexamethasone for chronic lung disease.

METHODS

In a pilot study 12 infants born at less than 30 weeks gestation who had received corticosteroids were given a supplementary Hib dose six weeks after completion of the primary immunisation course. Serum samples obtained before and at eight weeks following the fourth Hib dose were analysed for total level and avidity of anti-PRP antibody.

RESULTS

There was no significant increase in the geometric mean titre (GMT) of anti-PRP antibody resulting from the fourth Hib immunisation (GMT: pre 2.35 micro g/ml, post 2.24 micro g/ml, p = 0.79). A subgroup of six infants had subprotective antibody levels (<1.0 micro g/ml) after the primary immunisation course, which remained subprotective following the extra Hib immunisation. Despite the poor response in total antibody level, the study group showed a significant rise in PRP specific IgG avidity following the fourth immunisation (GMAI: pre 0.076, post 0.138, p = 0.043).

CONCLUSION

An additional Hib immunisation given to recently steroid treated preterm infants six weeks after completion of the primary schedule did not augment primary immunogenicity. However, increasing avidity may imply successful priming and long term immunity to Hib.

The S100 family heterodimer, MRP-8/14, binds with high affinity to heparin and heparan sulfate glycosaminoglycans on endothelial cells

The S100 family proteins MRP-8 (S100A8) and MRP-14 (S100A9) form a heterodimer that is abundantly expressed in neutrophils, monocytes, and some secretory epithelia. In inflamed tissues, the MRP-8/14 complex is deposited onto the endothelium of venules associated with extravasating leukocytes. To explore the receptor interactions of MRP-8/14, we use a model system in which the purified MRP-8/14 complex binds to the cell surface of an endothelial cell line, HMEC-1. This interaction is mediated by the MRP-14 subunit and is mirrored by recombinant MRP-14 alone. The cell surface binding of MRP-14 was blocked by heparin, heparan sulfate, and chondroitin sulfate B, and the binding sites were sensitive to heparinase I and trypsin treatment but not to chondroitinase ABC. Furthermore MRP-8/14 and MRP-14 did not bind to a glycosaminoglycan-minus cell line. MRP-14 has a high affinity for heparin (K(d) = 6.1 +/- 3.4 nm), and this interaction mimicked that with the endothelial cells. We therefore conclude that the MRP-8/14 complex binds to endothelial cells via the MRP-14 subunit interacting chiefly with heparan sulfate proteoglycans. CD36 and RAGE, two other putative receptors for MRP-8/14, were not expressed by HMEC-1 cells. This binding activity may explain the immobilization of the MRP-8/14 complex on endothelium that is observed in vivo.

Sonographic appearance of aggressive angiomyxoma of the scrotum

Aggressive angiomyxoma (AAM) is a rare, locally infiltrative tumor that occurs almost exclusively in the pelvic and perineal regions of women of childbearing age. We report the unusual case of a 26-year-old man with an AAM presenting as a slowly enlarging scrotal mass. Gray-scale scrotal sonography demonstrated a well-demarcated, hypoechoic, extratesticular, extraepididymal mass with multiple thin, echogenic internal septa. The mass arose inferior to the left testicle and displaced the testicle cephalad. Color Doppler sonography revealed surrounding vascularity but no Doppler signals within the mass. The testicles and epididymides demonstrated normal echogenicity and vascularity. Histologic examination of the excised mass revealed a well-demarcated, nonencapsulated lesion composed of spindle-shaped cells in a myxoid background with a prominent vascular component.

Extranodal lymphoplasmacytoid lymphoma (immunocytoma) presenting as small intestinal obstruction

A 57-year-old woman presented with intermittent symptoms of intestinal obstruction. Workup provided nondiagnostic radiologic studies. An exploratory laparotomy revealed a segmental dilatation in the proximal ileum, which showed diffuse thickening of the intestinal wall. Microscopic examination of the affected area disclosed a diffuse transmural infiltrate composed of small lymphocytes, mature plasma cells, and lymphoplasmacytoid cells in different stages of maturation associated with extracellular periodic acid-Schiff-positive material. In addition, serum protein electrophoresis showed a monoclonal immunoglobulin M kappa paraprotein. Postoperative workup did not demonstrate evidence of systemic involvement. The morphologic features and immunohistochemical and molecular analyses were consistent with lymphoplasmacytoid lymphoma (immunocytoma). We report an unusual case of primary extranodal immunocytoma involving the small intestine and discuss its clinicopathologic features.