Autophagy limits proliferation and glycolytic metabolism in acute myeloid leukemia.

Decreased autophagy contributes to malignancies, however it is unclear how autophagy impacts on tumour growth. Acute myeloid leukemia (AML) is an ideal model to address this as (i) patient samples are easily accessible, (ii) the hematopoietic stem and progenitor population (HSPC) where transformation occurs is well characterized, and (iii) loss of the key autophagy gene Atg7 in hematopoietic stem and progenitor cells (HSPCs) leads to a lethal pre-leukemic phenotype in mice. Here we demonstrate that loss of Atg5 results in an identical HSPC phenotype as loss of Atg7, confirming a general role for autophagy in HSPC regulation. Compared to more committed/mature hematopoietic cells, healthy human and mouse HSCs displayed enhanced basal autophagic flux, limiting mitochondrial damage and reactive oxygen species in this long-lived population. Taken together, with our previous findings these data are compatible with autophagy limiting leukemic transformation. In line with this, autophagy gene losses are found within chromosomal regions that are commonly deleted in human AML. Moreover, human AML blasts showed reduced expression of autophagy genes, and displayed decreased autophagic flux with accumulation of unhealthy mitochondria indicating that deficient autophagy may be beneficial to human AML. Crucially, heterozygous loss of autophagy in an MLL-ENL model of AML led to increased proliferation in vitro, a glycolytic shift, and more aggressive leukemias in vivo. With autophagy gene losses also identified in multiple other malignancies, these findings point to low autophagy providing a general advantage for tumour growth

The Immune Response to Melanoma Is Limited by Thymic Selection of Self-Antigens

The expression of melanoma-associated antigens (MAA) being limited to normal melanocytes and melanomas, MAAs are ideal targets for immunotherapy and melanoma vaccines. As MAAs are derived from self, immune responses to these may be limited by thymic tolerance. The extent to which self-tolerance prevents efficient immune responses to MAAs remains unknown. The autoimmune regulator (AIRE) controls the expression of tissue-specific self-antigens in thymic epithelial cells (TECs). The level of antigens expressed in the TECs determines the fate of auto-reactive thymocytes. Deficiency in AIRE leads in both humans (APECED patients) and mice to enlarged autoreactive immune repertoires. Here we show increased IgG levels to melanoma cells in APECED patients correlating with autoimmune skin features. Similarly, the enlarged T cell repertoire in AIRE−/− mice enables them to mount anti-MAA and anti-melanoma responses as shown by increased anti-melanoma antibodies, and enhanced CD4+ and MAA-specific CD8+ T cell responses after melanoma challenge. We show that thymic expression of gp100 is under the control of AIRE, leading to increased gp100-specific CD8+ T cell frequencies in AIRE−/− mice. TRP-2 (tyrosinase-related protein), on the other hand, is absent from TECs and consequently TRP-2 specific CD8+ T cells were found in both AIRE−/− and AIRE+/+ mice. This study emphasizes the importance of investigating thymic expression of self-antigens prior to their inclusion in vaccination and immunotherapy strategies

A cross-sectional study of the prevalence and associations of iron deficiency in a cohort of patients with chronic obstructive pulmonary disease

OBJECTIVES: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Iron deficiency, with or without anaemia, is associated with other chronic conditions, such as congestive heart failure, where it predicts a worse outcome. However, the prevalence of iron deficiency in COPD is unknown. This observational study aimed to determine the prevalence of iron deficiency in COPD and associations with differences in clinical phenotype. SETTING: University hospital outpatient clinic. PARTICIPANTS: 113 adult patients (65% male) with COPD diagnosed according to GOLD criteria (forced expiratory volume in 1 s (FEV(1)): forced vital capacity (FVC) ratio <0·70 and FEV(1) <80% predicted); with age-matched and sex-matched control group consisting of 57 healthy individuals. MAIN OUTCOME MEASURES: Prevalence of iron deficiency, defined as: any one or more of (1) soluble transferrin receptor >28.1 nmol/L; (2) transferrin saturation <16% and (3) ferritin <12 µg/L. Severity of hypoxaemia, including resting peripheral arterial oxygen saturation (SpO(2)) and nocturnal oximetry; C reactive protein (CRP); FEV(1); self-reported exacerbation rate and Shuttle Walk Test performance. RESULTS: Iron deficiency was more common in patients with COPD (18%) compared with controls (5%). In the COPD cohort, CRP was higher in patients with iron deficiency (median 10.5 vs 4.0 mg/L, p<0.001), who were also more hypoxaemic than their iron-replete counterparts (median resting SpO(2) 92% vs 95%, p<0.001), but haemoglobin concentration did not differ. Patients with iron deficiency had more self-reported exacerbations and a trend towards worse exercise tolerance. CONCLUSIONS: Non-anaemic iron deficiency is common in COPD and appears to be driven by inflammation. Iron deficiency associates with hypoxaemia, an excess of exacerbations and, possibly, worse exercise tolerance, all markers of poor prognosis. Given that it has been shown to be beneficial in other chronic diseases, intravenous iron therapy should be explored as a novel therapeutic option in COPD

Malaria and Age Variably but Critically Control Hepcidin Throughout Childhood in Kenya

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Anti-B16F10 antibodies serum levels are elevated.

<p>Mice of the indicated genotype were primed with 5×10⁶ irradiated B16F10 and challenged with 2.5×10⁵ live B16F10. <b>A</b> At time of sacrifice (when tumours reached 10 mm² or in the case of tumour-free mice after 50 days), serum was obtained. 1/500 diluted serum was used to stain B16F10. Secondary antibody was an anti-mouse pan Ig APC. <b>B</b> Serum was obtained before priming, 4 weeks after priming, or 16 days after live tumour challenge and used to stain B16F10. Naïve littermate controls or unprimed but challenged controls were included were indicated. Secondary antibodies used were anti-mouse IgM FITC (upper panel) or anti-mouse IgG FITC (lower panel). * p value by Mann-Whitney test comparing mean fluorescence of serum staining B16F10. These findings were reproduced three times with similar results with n>10 in each group.</p

MAA-specific CD8⁺ T cells present in TILs and draining LNs.

<p><b>A</b> Wildtype mice were injected with 10⁶ live B16F10 and 10 days later, TILs were isolated and stained for CD8 and TRP-2-specific TCR using tetramers. <b>B</b> and <b>C</b> Mice of indicated genotypes were primed and challenged with B16F10 cells, then frequencies of gp100, TRP-1 or TRP-2 tetramer positive cells in the CD8⁺ T cell population were plotted. Representative of two similarly conducted experiments.</p

AIRE^−/− mice reject tumour more efficiently than AIRE^+/+ littermate controls mice after priming.

<p><b>A</b> Mice of indicated genotype were challenged with B16F10, and tumour growth monitored over 75 days. <b>B</b> As treated in <b>A</b>, but mice were primed with irradiated B16F10 4 weeks prior to challenge. Curves were compared with Logrank test with p values indicated. Similar trends were found in at least 5 different experiments. In each of these experiments between 5 and 10 mice/group were included.</p

Expression of melanocyte antigens in medullary thymic epithelial cells.

<p>Medullary or cortical thymic epithelial cells were sorted by flow cytometry. <b>A</b> RT-PCR was performed on both types of cells using primers for GAPDH, gp100 and TRP-2. <b>B</b> Real time qPCR was performed using sorted populations. Expression relative to gp100 expression in AIRE^+/+ mTECs is shown for gp100 and TRP-2. Error bars are from duplicates.</p

APECED patients with skin features have increased anti-melanoma antibody levels.

<p>Cell lines were stained with serum obtained from APECED patients (2.D.G, 3.D.G., 4.U.G., 5.U.C., 6.M.R., 8.S.S., 12.F.M., 14.U.T.) diluted 1/500. Mm9, mm25, sk.mel23, sk.mel28, A2058 are human melanoma lines, TE671 a human rhabdomyosarcoma, and B16F10 murine melanoma cell line. Background using normal human serum was substracted and mean fluorescence indicated as follows −<0.5, +0.5–0.75, ++0.75–1, +++>1. The secondary antibodies used were <b>A</b> anti-human IgM FITC and <b>B</b> anti-human IgG FITC.</p

AIRE^−/− mice do not hyperreact to foreign antigen but respond better to certain melanocyte antigen than AIRE^+/+ littermate controls.

<p>Mice of the indicated genotype were injected s.c at the base of the tail with 4×10⁶ pfu of lentivirus expressing the indicated peptides. Serial samples of blood cells (left panels) were stained for CD8 and MHC class I tetramers specific for T cells responding to the injected peptides (example at peak of response in right panels). <b>A</b> LCMV-derived foreign gp33 presented by H-2D^b<b>B</b> mouse TRP-2 presented by H-2K^b<b>C</b> gp100 presented by H-2D^b.</p