Jacques Bienvenu

T-bet and Eomes instruct the development of two distinct natural killer cell lineages in the liver and in the bone marrow

Mutually exclusive expression of T-bet and Eomes drives the development of distinct NK cell lineages with complementary functions.

The metabolic checkpoint kinase mTOR is essential for IL-15 signaling during the development and activation of NK cells

Interleukin 15 (IL-15) controls both the homeostasis and the peripheral activation of natural killer (NK) cells. The molecular basis for this duality of action remains unknown. Here we found that the metabolic checkpoint kinase mTOR was activated and boosted bioenergetic metabolism after exposure of NK cells to high concentrations of IL-15, whereas low doses of IL-15 triggered only phosphorylation of the transcription factor STAT5. mTOR stimulated the growth and nutrient uptake of NK cells and positively fed back on the receptor for IL-15. This process was essential for sustaining NK cell proliferation during development and the acquisition of cytolytic potential during inflammation or viral infection. The mTORC1 inhibitor rapamycin inhibited NK cell cytotoxicity both in mice and humans; this probably contributes to the immunosuppressive activity of this drug in different clinical settings.

TGF-β inhibits the activation and functions of NK cells by repressing the mTOR pathway

Blocking TGF-β signaling in natural killer cells enhances their metabolism and ability to kill tumor cells. Relieving NK cell suppression The immunosuppressive cytokine transforming growth factor–β (TGF-β) has beneficial effects when it resolves inflammation and prevents autoimmunity, but not when it inhibits antitumor immune responses. Viel et al. found that TGF-β signaling in mouse and human natural killer (NK) cells, cytotoxic cells that target tumor cells, inhibited the activation of the kinase mTOR, a central regulator of cellular metabolism and cytotoxic function. NK cells deficient in a TGF-β receptor subunit showed enhanced antitumor activity in mouse models of metastasis, suggesting that enhancing metabolism in NK cells may provide a therapeutic strategy to kill cancer cells. Transforming growth factor–β (TGF-β) is a major immunosuppressive cytokine that maintains immune homeostasis and prevents autoimmunity through its antiproliferative and anti-inflammatory properties in various immune cell types. We provide genetic, pharmacologic, and biochemical evidence that a critical target of TGF-β signaling in mouse and human natural killer (NK) cells is the serine and threonine kinase mTOR (mammalian target of rapamycin). Treatment of mouse or human NK cells with TGF-β in vitro blocked interleukin-15 (IL-15)–induced activation of mTOR. TGF-β and the mTOR inhibitor rapamycin both reduced the metabolic activity and proliferation of NK cells and reduced the abundances of various NK cell receptors and the cytotoxic activity of NK cells. In vivo, constitutive TGF-β signaling or depletion of mTOR arrested NK cell development, whereas deletion of the TGF-β receptor subunit TGF-βRII enhanced mTOR activity and the cytotoxic activity of the NK cells in response to IL-15. Suppression of TGF-β signaling in NK cells did not affect either NK cell development or homeostasis; however, it enhanced the ability of NK cells to limit metastases in two different tumor models in mice. Together, these results suggest that the kinase mTOR is a crucial signaling integrator of pro- and anti-inflammatory cytokines in NK cells. Moreover, we propose that boosting the metabolic activity of antitumor lymphocytes could be an effective strategy to promote immune-mediated tumor suppression.

PRKDC mutations associated with immunodeficiency, granuloma, and autoimmune regulator–dependent autoimmunity

BACKGROUNDnPRKDC encodes for DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a kinase that forms part of a complex (DNA-dependent protein kinase [DNA-PK]) crucial for DNA double-strand break repair and V(D)J recombination. In mice DNA-PK also interacts with the transcription factor autoimmune regulator (AIRE) to promote central T-cell tolerance.nnnOBJECTIVEnWe sought to understand the causes of an inflammatory disease with granuloma and autoimmunity associated with decreasing T- and B-cell counts over time that had been diagnosed in 2 unrelated patients.nnnMETHODSnGenetic, molecular, and functional analyses were performed to characterize an inflammatory disease evocative of a combined immunodeficiency.nnnRESULTSnWe identified PRKDC mutations in both patients. These patients exhibited a defect in DNA double-strand break repair and V(D)J recombination. Whole-blood mRNA analysis revealed a strong interferon signature. On activation, memory Txa0cells displayed a skewed cytokine response typical of TH2 and TH1 but not TH17. Moreover, mutated DNA-PKcs did not promote AIRE-dependent transcription of peripheral tissue antigens inxa0vitro. The latter defect correlated inxa0vivo with production of anti-calcium-sensing receptor autoantibodies, which are typically found in AIRE-deficient patients. In addition, 9 months after bone marrow transplantation, patient 1xa0had Hashimoto thyroiditis, suggesting that organ-specific autoimmunity might be linked to nonhematopoietic cells, such as AIRE-expressing thymic epithelial cells.nnnCONCLUSIONnDeficiency of DNA-PKcs, a key AIRE partner, can present as an inflammatory disease with organ-specific autoimmunity, suggesting a role for DNA-PKcs in regulating autoimmune responses and maintaining AIRE-dependent tolerance in human subjects.

Usefulness of basophil activation tests for the diagnosis of IgE-mediated allergy to quinolones

vidual (5). Food Standards Code has not eliminated two significant problems, dealing with the use by manufacturers of ‘may contain’ statements, as well as complex terminology which are still extensive. These reveal that the guidance is insufficient and limited to stating, which allergenic substances should be declared on a label. This study reveals consumers’ confusion on ingredients contained in commercial food products. There is profound need to state exact terms for use for each food allergen and allow only limited use of ‘may contain’ statements to avoid misleading labelling.

Differential dose effect of fish oil on inflammation and adipose tissue gene expression in chronic kidney disease patients

OBJECTIVEnThe beneficial effects of ω-3 polyunsaturated fatty acids (PUFAs) in cardiovascular disease are partly attributed to their anti-inflammatory properties. Their potential effect on the adipose tissue of chronic kidney disease (CKD) patients has never been explored.nnnMETHODSnTo determine the metabolic effect of supplementation with two different doses of fish oil (FO), 12 non-dialyzed patients with stage IV/V CKD were randomly allocated to receive 1.8 g or 3.6 g/d of ω-3 PUFA for 10 wk. Metabolic parameters, adipose tissue function, and gene expression were evaluated at baseline and 10 wk.nnnRESULTSnBody weight, fat mass, energy intake, fasting glucose, and insulin were unchanged. The daily intake of 3.6 g of ω-3 PUFA resulted in decreased serum triacylglycerol and increased high-density lipoprotein cholesterol, whereas low-density lipoprotein cholesterol increased with 1.8 g of ω-3 PUFA. Serum adiponectin, leptin, C-reactive protein, and tumor necrosis factor-α were not modified in either group. Interleukin-6 levels tended to decrease with 1.8 g of ω-3 PUFA. Additionally, a subset of inflammation-related genes (CD68 and MMP9) was reduced in subcutaneous adipose tissue in this group. Adiponectin, leptin, and adipoR2 gene expression were upregulated with 3.6 g of ω-3 PUFA.nnnCONCLUSIONSnA moderate dose of FO alters the gene expression profile of adipose tissue to a more antiinflammatory status. Higher doses of FO have a favorable effect on lipid profile and lead to the upregulation of adipokines gene expression suggesting a different dose response to ω-3 PUFA administration in patients with CKD.

Immunochemical assays of serum proteins: a European external quality assessment survey and the effects of calibration procedures on interlaboratory agreement

An external quality assessment survey of immunochemical assays of 9 proteins (immunoglobulins G, A and M, complement components C3 and C4, alpha1-antitrypsin, orosomucoid, haptoglobin and transferrin) in 5 European countries (Austria, France, Hungary, Italy and UK) showed inter-country differences in the mean values obtained. Reprocessing of the results using one of the two specimens distributed as a calibrant effectively eliminated or reduced substantially these differences. Consideration of the methods used by participants confirmed previous indications from national surveys that the differences were due to lack of agreement among commercial calibrants. Such interlaboratory variations were also minimised by the calibration in this survey. The role of European working calibration materials in ensuring interlaboratory agreement on an international basis is discussed.

CD4 monoclonal antibody administration in atopic dermatitis

BACKGROUNDnAtopic dermatitis (AD) is a chronic inflammatory dermatosis that probably involves a dysregulated activation of helper T cells, type 2 (Th2 cells). Severe refractory AD can be controlled by cyclosporine treatment.nnnOBJECTIVEnWe attempted to determine whether short-term CD4 monoclonal antibody (mAb) therapy could improve severe AD in adults.nnnMETHODSnThe CD4 mAb, B-F5, was infused over 2 days in three patients with severe refractory AD and, for control purposes, in two patients with severe psoriasis.nnnRESULTSnAdministration of B-F5 was well tolerated, despite moderate first dose side effects. Clinical improvement was observed in two patients. In the third patient, a dramatic worsening occurred between 8 and 30 days after treatment, associated with an increased percentage of activated CD4+, CD25+, HLA-DR+, and CD45RO+ cells and peripheral blood eosinophilia. The same CD4 mAb administered to two patients with severe psoriasis induced marked clinical improvement of the lesions.nnnCONCLUSIONnAlthough CD4 mAb infusion may be potentially useful in the treatment of AD, the risk of aggravating the Th1/Th2 imbalance in AD should be considered in the design of future protocols.

Carbonic anhydrase III: a new target for autoantibodies in autoimmune diseases

The objective of this study was to identify new autoantibodies that could be useful for the diagnosis of rheumatoid arthritis (RA) using immunoblotting on synovial membrane proteins which represent the best source of candidate RA autoantigens. A new target protein with a molecular weight of 26 kDa was found to be recognized by autoantibodies in RA sera and was identified using MALDI-TOF mass spectrometry and second-dimension electrophoresis as carbonic anhydrase III (CAIII). Three similar protein spots at 26 kDa were recognized by both human sera and monoclonal antibody (mAb) directed against CAIII on immunoblotting using the human recombinant CAIII. Interestingly, CAIII expression within the synovial membrane was not observed in non-RA patients and was differentially expressed among RA patients. The sensitivity of these new autoantibodies for RA, using an immunoenzymatic technique, was 17%. Specificity was high when comparing non-autoimmune diseases (100%), while it was found to be weak (67%) when comparing some other autoimmune diseases, and particularly systemic lupus erythematosus (SLE). In conclusion, this study demonstrates that these new autoantibodies against CAIII are not restricted to RA. However the expression of CAIII in the synovial membrane of RA warrants further investigation of the pathophysiological relevance of this finding.

Calcium-sensing receptor autoantibodies in primary hyperparathyroidism

BACKGROUNDnMutations in the extracellular calcium-sensing receptor (CaSR) gene are known to be implicated in some cases of primary hyperparathyroidism. However, not all patients display such mutations and so the mechanisms of primary hyperparathyroidism are still largely unknown. An autoimmune origin has been suggested, as autoantibodies against the CaSR have been detected in some patients. The aim of our study was to investigate the presence of CaSR autoantibodies in a large cohort of patients with primary hyperparathyroidism.nnnMETHODSnSeventy-five patients were tested for the presence of anti-parathyroid antibodies using an immunoblotting assay with the recombinant extracellular domain of the human CaSR and an immunofluorescence technique with parathyroid adenoma.nnnRESULTSnFive of 75 (6.7%) patients had CaSR autoantibodies. There was no statistically significant difference in the decrease of parathyroid hormone (PTH) level after surgery between patients with or without autoantibodies. Histological examination of parathyroid tissue did not show greater lymphocytic infiltration in patients with autoantibodies than in those without.nnnCONCLUSIONSnThis study confirmed that some patients with primary hyperparathyroidism displayed CaSR autoantibodies. The pathophysiological role of these autoantibodies in hyperparathyroidism needs to be further elucidated.