Elisa Binda

Langerhans Cells Facilitate Epithelial DNA Damage and Squamous Cell Carcinoma

The Dark Side of Langerhans Cells Several immune cell populations reside in the skin and are thought to provide a protective barrier against infections and to act as sentinels against malignant transformation. However, studies in mice that lack Langerhans cells, a subset of dendritic cells, have suggested that these cells may actually promote tumorigenesis. Using a mouse model of squamous cell carcinoma, Modi et al. (p. 104) now reveal how Langerhans cells may promote the transformation of skin epithelial cells. In response to the carcinogen 7,12-dimethylbenz[α]anthracene (DMBA), Langerhans cells increased their expression of the cytochrome P-450 enzyme CYP1B1, which can metabolize DMBA to the mutagenic DMBA-trans-3,4-diol. Thus, besides their functions in regulating the adaptive immune response, Langerhans cells may participate in the metabolism of environmental carcinogens. A specialized immune cell population in the skin promotes tumorigenesis by metabolizing environmental carcinogens. Polyaromatic hydrocarbons (PAHs) are prevalent, potent carcinogens, and 7,12-dimethylbenz[a]anthracene (DMBA) is a model PAH widely used to study tumorigenesis. Mice lacking Langerhans cells (LCs), a signatory epidermal dendritic cell (DC), are protected from cutaneous chemical carcinogenesis, independent of T cell immunity. Investigation of the underlying mechanism revealed that LC-deficient skin was relatively resistant to DMBA-induced DNA damage. LCs efficiently metabolized DMBA to DMBA-trans-3,4-diol, an intermediate proximal to oncogenic Hras mutation, and DMBA-treated LC-deficient skin contained significantly fewer Hras mutations. Moreover, DMBA-trans-3,4-diol application bypassed tumor resistance in LC-deficient mice. Additionally, the genotoxic impact of DMBA on human keratinocytes was significantly increased by prior incubation with human-derived LC. Thus, tissue-associated DC can enhance chemical carcinogenesis via PAH metabolism, highlighting the complex relation between immune cells and carcinogenesis.

Adjuvanted influenza-H1N1 vaccination reveals lymphoid signatures of age-dependent early responses and of clinical adverse events

Adjuvanted vaccines afford invaluable protection against disease, and the molecular and cellular changes they induce offer direct insight into human immunobiology. Here we show that within 24 h of receiving adjuvanted swine flu vaccine, healthy individuals made expansive, complex molecular and cellular responses that included overt lymphoid as well as myeloid contributions. Unexpectedly, this early response was subtly but significantly different in people older than ∼35 years. Wide-ranging adverse clinical events can seriously confound vaccine adoption, but whether there are immunological correlates of these is unknown. Here we identify a molecular signature of adverse events that was commonly associated with an existing B cell phenotype. Thus immunophenotypic variation among healthy humans may be manifest in complex pathophysiological responses.

Association between levels of C-reactive protein and leukocytes and cancer: Three repeated measurements in the Swedish AMORIS study

Objective: To study levels of C-reactive protein (CRP) and leukocytes, as inflammatory markers, in the context of cancer risk. Methods: From the Apolipoprotein MOrtality RISk (AMORIS) study, we selected 102,749 persons with one measurement and 9,273 persons with three repeated measurements of CRP and leukocytes. Multivariate Cox proportional hazards regression was applied to categories of CRP (<10, 10–15, 15–25, 25–50, >50 g/L) and quartiles of leukocytes. An inflammation-based predictive score (IPS) indicated whether someone had CRP levels of more than 10 mg/L combined with leukocytes of more than 10 × 109/L. Reverse causality was assessed by excluding those with less than 3, 5, or 7 years of follow-up. To analyze repeated measurements of CRP and leukocytes, the repeated IPS (IPSr) was calculated by adding the IPS of each measurement. Results: In the cohort with one measurement, there was a positive trend between CRP and risk of developing cancer, with the lowest category being the 0.99 (0.92–1.06), 1.28 (1.11–1.47), 1.27 (1.09–1.49), and 1.22 (1.01–1.48) for the second to fifth categories, respectively. This association disappeared when excluding those with follow-up of less than 3, 5, or 7 years. The association between leukocytes and cancer was slightly stronger. In the cohort with repeated measurements, the IPSr was strongly associated with cancer risk: 1.87 (1.33–2.63), 1.51 (0.56–4.06), and 4.46 (1.43–13.87) for IPSr = 1, 2, and 3 compared with IPSr = 0. The association remained after excluding those with follow-up of less than 1 year. Conclusions and Impact: Our large, prospective cohort study adds evidence for a link between inflammatory markers and cancer risk by using repeated measurements and ascertaining reverse causality. Cancer Epidemiol Biomarkers Prev; 20(3); 428–37. ©2011 AACR.

Immunoglobulin E and cancer: a meta-analysis and a large Swedish cohort study

We quantified associations between IgE and cancer in a meta-analysis and cohort study. Pubmed and Embase were searched to extract information using predefined inclusion criteria. In the Apolipoprotein MOrtality RISk (AMORIS) database, 24,820 persons had IgE measurements. Multivariate Cox proportional hazard models were used to analyze associations between IgE and cancer. Twenty-seven studies were reviewed from which seven case–control studies were included for analysis. The pooled relative risk (random effects model) was 0.97 (95% CI 0.86–1.09). Cell types of tumor origin (mesenchymal tissue or cells of the nervous system, lymphatic or hematopoietic tissue, and epithelium) modified the effect. In the AMORIS cohort, 862 persons developed cancer. Hazard ratios comparing quartiles of IgE were similar to the findings in the meta-analysis (HR 0.87 (95% CI 0.72–1.06); 0.94 (0.78–1.14); 0.90 (0.74–1.10) for the 2nd, 3rd, and 4th quartile compared to the 1st quartile), but there was no pattern by tumor origin. Both studies showed a weak inverse association between IgE and cancer, but a pattern by cancer type was only seen in the meta-analysis. Our findings suggest the need for prospective studies studying IgE and cancer. Measurements of IgE should be combined with other information, e.g., bio-banked samples containing other key immunological discriminators.

Risk of prostate cancer is not associated with levels of C-reactive protein and other commonly used markers of inflammation

Most population‐based studies studied the association between inflammation and prostate cancer (PCa) by assessing C‐reactive protein (CRP). As these findings have shown inconsistent results, we aimed to also study different markers that have been commonly taken as indications of inflammation. A cohort based on four groups of men (n = 34,891), according to age at cohort entry (45, 55, 65 and 75 years), with measurements of glucose, triglycerides, total cholesterol, haptoglobin, albumin, hemoglobin and leukocytes were selected from the Apolipoprotein Mortality Risk database. A total of 17,937 men had measurements of non‐high‐sensitive CRP. Multivariate Cox proportional hazard models were used to analyze associations between inflammatory markers and PCa. A total of 49 of 12,063 men developed PCa in the age 45 group, whereas 207 of 9,940, 472 of 8,266 and 276 of 3,618 were diagnosed in the age 55, 65 and 75 groups, respectively. Mean follow‐up time was 7.5 years (SD: 3.9). No markers showed an association with PCa risk, nor was there a trend by quartiles or an indication for different PCa risks by strata of hypercholesterolemia, hyperglycemia and hypertriglyceridemia status. The studied markers were not found to be associated with PCa risk. These null findings might be due to methodological issues; however, it is unlikely that strong and long‐lasting associations between inflammation and PCa risk were missed as this was a large database with long follow‐up. This indicates need for international consensus on appropriate inflammatory markers in the context of cancer that may be practically applied in large studies.

What does it take to be healthy? Investigating immune-deficiency in non-immunodeficient scenarios

Viral pandemics can arise rapidly and unexpectedly, necessitating the prompt development and administration of relevant vaccines. Nonetheless, despite our impressive knowledge of immunological pathways, cell-types, molecules, and pathways, we have little understanding of how effective, integrated immune responses to vaccination are composed. Indeed, we have conspicuously poor understanding of normality in human immune function, and hence few effective measures of it [1]. Our study was designed to redress this situation. Longitudinal molecular, cellular, and functional immune-monitoring was undertaken in a cohort of >150 healthy volunteers, resident in the UK, either side of a richly adjuvanted H1N1 vaccine, with blood sampling at day -7; day 0 [vaccine]; day +1; day +7; day +14; day +63. The data to be presented will reflect gene expression profiling in peripheral blood mononuclear cells, multiplex detection of serum cytokines and chemokines and cell phenotyping, as reconciled with initial clinical phenotype [fever/adverse events [AE] vs asymptomatic] and downstream outcome measures. The results attest to the practicality of immune-monitoring, and its capacity to provide new knowledge concerning the stability and dynamics of human immune measures. Of note, gene expression profiles diverged overtly at day +1, according to symptoms, but largely re-converged by day +7 to a B cell-rich response. Specific genes were associated with AE, but these were not those that were anticipated a priori. Highly significant changes in numerous serum inflammatory markers were detected at day +1. Hence, the study highlights the potential of novel markers of immune responsiveness. The study likewise permits the search for specific markers and overall immune profiles that predict the functional response to vaccination. The intrinsic content of such studies, and their comparison with similar studies conducted elsewhere, help establish the normal range of human immune function and should thereby facilitate the identification of immune pathology. At the same time, logistical and other challenges relating to immune monitoring will be discussed.

Quantitative isolation of mouse and human intestinal intraepithelial lymphocytes by elutriation centrifugation.

Intestinal intraepithelial lymphocytes (IEL) are specialized subsets of T cells with distinct functional capacities. While some IEL subsets are circulating, others such as CD8alphaalpha TCRalphabeta IEL are believed to represent non-circulating resident T cell subsets [Sim, G.K., Intraepithelial lymphocytes and the immune system. Adv. Immunol., 1995. 58: 297-343.]. Current methods to obtain enriched preparations of intraepithelial lymphocytes are mostly based on Percoll density gradient or magnetic bead-based technologies [Lundqvist, C., et al., Isolation of functionally active intraepithelial lymphocytes and enterocytes from human small and large intestine. J. Immunol. Methods, 1992. 152(2): 253-263.]. However, these techniques are hampered by a generally low yield of isolated cells, and potential artifacts due to the interference of the isolation procedure with subsequent functional assays, in particular, when antibodies against cell surface markers are required. Here we describe a new method for obtaining relatively pure populations of intestinal IEL (55-75%) at a high yield (>85%) by elutriation centrifugation. This technique is equally suited for the isolation and enrichment of intraepithelial lymphocytes of both mouse and human origin. Time requirements for fractionating cell suspensions by elutriation centrifugation are comparable to Percoll-, or MACS-based isolation procedures. Hence, the substantially higher yield and the consistent robust enrichment for intraepithelial lymphocytes, together with the gentle treatment of the cells during elutriation that does not interfere with subsequent functional assays, are important aspects that are in favor of using this elegant technology to obtain unmanipulated, unbiased populations of intestinal intraepithelial lymphocytes, and, if desired, also of pure epithelial cells.

Immunosurveillance by gamma delta T cells - lessons from the cancer field

The most common contemporary depiction of the immune response is an early innate response, mounted by myeloid cells, followed by a delayed adaptive lymphoid responses mounted by lymphocytes. This depiction is based on myriad compelling data sets and has made powerful predictions with biological and clinical relevance. Nonetheless, it seems incomplete. Thus, there are lymphocytes that respond very rapidly, commonly to self-encoded molecules over-expressed by dysregulated and/or transformed tissues and cells. The evidence for such “lymphoid stress-surveillance” by gamma delta T cells has been provided by animal models, and supports ongoing clinical investigations of the potential host-protective role of gamma delta T cells in cancer.