Understanding the murine cutaneous dendritic cell network to improve intradermal vaccination strategies.

Dendritic cells (DCs) form a heterogeneous group of antigen presenting cells that play different roles in tissue immunity. Recent studies have revealed the presence of distinct DC populations in murine skin, highlighting the complexity of the cutaneous DC network. In this review, we will define the major DC subsets that populate the different layers of the skin, focusing on their origin and the mechanisms controlling their homeostasis. We will also review recent evidence underlining the functional specialization of dermal DC subsets and its relevance in the design of novel vaccine approaches.

Development of CD8alpha-positive dendritic cells from a common myeloid progenitor.

Dendritic cells (DCs) are critical in both initiating adaptive immune responses and maintaining tolerance to self antigens. These apparently contradictory roles have been suggested to depend on different subsets of DCs that arise from either myeloid or lymphoid hematopoietic origins, respectively. Although DC expression of CD8alpha is attributed to a lymphoid origin, here we show that both CD8alpha+ and CD8alpha- DCs can arise from clonogenic common myeloid progenitors in both thymus and spleen. Thus, expression of CD8alpha is not indicative of a lymphoid origin, and phenotypic and functional differences among DC subsets are likely to reflect maturation status rather than ontogeny.

[Pulmonary tumor thrombotic microangiopathy]. / Microangiopathie thrombotique tumorale pulmonaire.

Pulmonary tumor thrombotic microangiopathy syndrome is a rare clinicopathological entity in which tumor cell micro-emboli in the pulmonary microcirculation induced thrombotic microangiopathy. This can cause respiratory failure, and acute or sub-acute right heart failure. Histological features include micro tumor emboli in the small arteries and arterioles of the lung associated with thrombus formation and fibro-cellular and fibro-muscular intimal proliferation. The diagnosis is however extremely difficult to make before death. Thus, most of the observations reported are based on autopsy data. Very rare diagnostic observations made before death suggest the potential effectiveness of chemotherapy. Many details remain to be elucidated, interdisciplinary research is a priority with close collaboration between pathologists and clinicians to better understand this, often fatal, syndrome. It may be that the use of targeted therapies will improve the very poor prognosis allowing survival of several weeks or months after diagnosis.

Altered peripheral immune profiles in treatment-resistant depression: response to ketamine and prediction of treatment outcome.

A subset of patients with depression have elevated levels of inflammatory cytokines, and some studies demonstrate interaction between inflammatory factors and treatment outcome. However, most studies focus on only a narrow subset of factors in a patient sample. In the current study, we analyzed broad immune profiles in blood from patients with treatment-resistant depression (TRD) at baseline and following treatment with the glutamate modulator ketamine. Serum was analyzed from 26 healthy control and 33 actively depressed TRD patients free of antidepressant medication, and matched for age, sex and body mass index. All subjects provided baseline blood samples, and TRD subjects had additional blood draw at 4 and 24 h following intravenous infusion of ketamine (0.5 mg kg-1). Samples underwent multiplex analysis of 41 cytokines, chemokines and growth factors using quantitative immunoassay technology. Our a priori hypothesis was that TRD patients would show elevations in canonical pro-inflammatory cytokines; analyses demonstrated significant elevation of the pro-inflammatory cytokine interleukin-6. Further exploratory analyses revealed significant regulation of four additional soluble factors in patients with TRD. Several cytokines showed transient changes in level after ketamine, but none correlated with treatment response. Low pretreatment levels of fibroblast growth factor 2 were associated with ketamine treatment response. In sum, we found that patients with TRD demonstrate a unique pattern of increased inflammatory mediators, chemokines and colony-stimulating factors, providing support for the immune hypothesis of TRD. These patterns suggest novel treatment targets for the subset of patients with TRD who evidence dysregulated immune functioning.

Dendritic cell development from common myeloid progenitors.

Dendritic cells (DCs) are professional antigen-presenting cells which both initiate adaptive immune responses and control tolerance to self-antigens. It has been suggested that these different effects on responder cells depend on subsets of DCs arising from either myeloid or lymphoid hematopoietic origins. In this model, CD8 alpha+ Mac-1- DCs are supposed to be of lymphoid while CD8 alpha- Mac-1+ DCs are supposed to be of myeloid origin. Here we summarize our findings that both CD8 alpha+ and CD8 alpha- DCs can arise from clonogenic common myeloid progenitors (CMPs) in both thymus and spleen. Therefore CD8 alpha expression DCs does not indicate a lymphoid origin and differences among CD8 alpha+ and CD8 alpha- DCs might rather reflect maturation status than ontogeny. On the basis of transplantation studies, it seems likely that most of the DCs in secondary lymphoid organs and a substantial fraction of thymic DCs are myeloid-derived.

[Inappropriate antidiuretic hormone secretion disclosing a second primary lung cancer 5 years after complete remission of a small cell lung carcinoma]. / Sécrétion inappropriée d'hormone antidiurétique (SIHAD) révélatrice d'un second cancer 5 ans après rémission complète d'un carcinome bronchique à petites cellules (CBPC).

We report the case of a female patient who developed a second contralateral small cell lung carcinoma (SCLC) five years after a right upper lobe SCLC treated by sequential chemotherapy and chest radiation therapy. This second primary neoplasia was revealed by an isolated and symptomatic syndrome of inappropriate antidiuretic hormone secretion. Specific evolution of long-term survivors after SCLC are discussed, including consequences of combined radiochemotherapy and poor prognosis associated with persistence of tobacco smoking exposure.

[Cardiac side effects of anti-HIV agents]. / Complications cardiaques des médicaments au cours de l'infection par le VIH.

Both nature and prognosis of cardiac complications occurring in patients infected by the Human Immunodeficiency Virus-1 (HIV-1) have changed considerably since the introduction of highly acive and anti-retroviral triple therapy ("HART"). Opportunist cardiac infections have thus been displaced and side effects of drugs now occupy the primary aetiological role. Torsades de pointe may be exceptionally triggered by anti-infectious agents such as pentacarinat or trimethoprime-sulfamethoxazole, as are those induced by the association of ketoconazole and terfenadine or cisapride, the dangers of which are well known and the prevention more effective, especially with the association with HIV antiproteases which inhibit the cytochrome P450. The diagnosis of iatrogenic myocardial dysfunction is more difficult, except when it occurs acutely as with phosphonoformate (Foscarnet), or interleukine-2. Progressive cardiomyopathy caused by -interferon and dideoxynucleosides (zidovudine, didanosine and zalcitabine), reversible on withdrawal of the drug responsible in half the cases, should be distinguished from those due to the HIV itself (therapeutic relay) or to another associated cause (alcohol, coronary artery disease). The coronary complications of diseases treated by antiproteases usually occur in smokers whose cholesterol and triglyceride levels are rapidly increased with HAART. In a series of 9 patients (amongst 700 treated with the antiproteases), after the acute phase of myocardial infarction during which the interventional approach is often preferred, the medium-term prognosis is relatively good, on condition that the patients correct the hyperlipidaemia and give up smoking.

Molecular interaction of acetylcholinesterase with carnosic acid derivatives: a neuroinformatics study.

Alzheimer's disease is a progressive degenerative disease of the brain marked by gradual and irreversible declines in cognitive functions. Acetylcholinesterase (AChE) plays a biological role in the termination of nerve impulse transmissions at cholinergic synapses by rapid hydrolysis of its substrate, "acetylcholine". The deficit level of acetylcholine leads to deprived nerve impulse transmission. Thus the cholinesterase inhibitors would reverse the deficit in acetylcholine level and consequently may reverse the memory impairments, which is characteristic of the Alzheimer's disease. The molecular interactions between AChE and Carnosic acid, a well known antioxidant substance found in the leaves of the rosemary plant has always been an area of interest. Here in this study we have performed in silico approach to identify carnosic acid derivatives having the potential of being a possible drug candidate against AChE. The best candidates were selected on the basis of the results of different scoring functions.

Discontinuation of empirical antibiotic therapy in neutropenic acute myeloid leukaemia patients with fever of unknown origin: is it ethical?

Based on recommendations of the ECIL-4, we prospectively evaluated discontinuation of empirical antibiotic therapy in high-risk neutropenic acute myeloid leukaemia patients with fever of unknown origin. Seven patients (median neutropenia duration 30 days) were included. Four of them remained afebrile but quickly recovered from neutropenia. The other three had rapid recurrent fever. Two of these three patients had bacteraemia with susceptible strains and one of them was transferred to the ICU for septic shock. Median duration of sparing of antibiotics for the seven patients was 3 days (2-4). Because of these limited results the study was stopped.

Interleukin-22 binding protein (IL-22BP) is constitutively expressed by a subset of conventional dendritic cells and is strongly induced by retinoic acid.

Interleukin-22 (IL-22) is mainly produced at barrier surfaces by T cells and innate lymphoid cells and is crucial to maintain epithelial integrity. However, dysregulated IL-22 action leads to deleterious inflammation and is involved in diseases such as psoriasis, intestinal inflammation, and cancer. IL-22 binding protein (IL-22BP) is a soluble inhibitory IL-22 receptor and may represent a crucial regulator of IL-22. We show both in rats and mice that, in the steady state, the main source of IL-22BP is constituted by a subset of conventional dendritic cells (DCs) in lymphoid and non-lymphoid tissues. In mouse intestine, IL-22BP was specifically expressed in lamina propria CD103(+)CD11b(+) DC. In humans, IL-22BP was expressed in immature monocyte-derived DC and strongly induced by retinoic acid but dramatically reduced upon maturation. Our data suggest that a subset of immature DCs may actively participate in the regulation of IL-22 activity in the gut by producing high levels of IL-22BP.

Progressive contraction of the latent HIV reservoir around a core of less-differentiated CD4⁺ memory T Cells.

In patients who are receiving prolonged antiretroviral treatment (ART), HIV can persist within a small pool of long-lived resting memory CD4(+) T cells infected with integrated latent virus. This latent reservoir involves distinct memory subsets. Here we provide results that suggest a progressive reduction of the size of the blood latent reservoir around a core of less-differentiated memory subsets (central memory and stem cell-like memory (TSCM) CD4(+) T cells). This process appears to be driven by the differences in initial sizes and decay rates between latently infected memory subsets. Our results also suggest an extreme stability of the TSCM sub-reservoir, the size of which is directly related to cumulative plasma virus exposure before the onset of ART, stressing the importance of early initiation of effective ART. The presence of these intrinsic dynamics within the latent reservoir may have implications for the design of optimal HIV therapeutic purging strategies.

Thyroid and bone: macrophage-derived TSH-ß splice variant increases murine osteoblastogenesis.

It is now firmly established that TSH may influence the physiology and patho-physiology of bone by activating osteoblasts and inhibiting osteoclast activity resulting in relative osteoprotection. Whether this influence is directly exerted by pituitary-derived TSH in vivo is less certain, because we have previously reported that the suppression of pituitary TSH does not remove such protection. Here, we have characterized the functional relevance of a novel form of the TSH-ß subunit, designated TSH-ßv, known to be produced by murine bone marrow cells. We found that fresh bone marrow-derived macrophages (MØs) preferentially produced TSH-ßv and, when cocultured with CHO cells engineered to overexpress the full-length TSH receptor, were able to generate the production of intracellular cAMP; a phenomenon not seen in control CHO cells, such results confirmed the bioactivity of the TSH variant. Furthermore, cocultures of MØs and osteoblasts were shown to enhance osteoblastogenesis, and this phenomenon was markedly reduced by antibody to TSH-ß, suggesting direct interaction between MØs and osteoblasts as observed under the electron microscope. These data suggest a new paradigm of local modulation of bone biology by a MØ-derived TSH-like molecule and raise the question of the relative contribution of local vs pituitary-derived TSH in osteoprotection.

[Evaluating the nutritional status of a lung cancer patient is an important element in patient management]. / L'évaluation du statut nutritionnel du patient suivi pour un cancer bronchique est un élément important de la prise en charge.

Nutritional status assessment during the comprehensive management of patients treated for cancer is becoming increasingly necessary. Various data are currently available which show a relationship between the nutritional status and certain morbidity-mortality parameters. In contrast, there is a paucity of data concerning lung cancer. A relationship between survival and the nutritional status has been found in the literature, exclusively in advanced stages of lung cancer. Unlike that observed in oncological digestive tract surgery, where artificial nutrition is recommended preoperatively in severely malnourished patients, no link has been evidenced between postoperative morbidity and mortality and the preoperative nutritional status in lung surgery. The scientific nutritional societies simply recommend preoperative nutritional assessment. Reflection on management of malnourished patients receiving chemotherapy is still "archaic" and recent studies and recommendations are lacking. Although largely prescribed, oral nutritional supplements have not proven efficient and patient compliance will probably have to be improved. According to "good nutrition practice" rules, the digestive tube should be used when it is functional and in theory, enteral nutrition is indicated in this situation. In addition to the lack of clinical studies, one of the obstacles to its use is cultural with the need to obtain not only patient approval but also that of the prescriber. Parenteral nutrition was discredited in earlier studies. It should probably be reevaluated in the context of new chemotherapeutic molecules and a different way of handling nutrition care. The physiological concept of omega-3 fatty acid modulation of inflammation is of interest in animal studies but the clinical modalities of use remain to be defined and determined. The role of nutrition in the management of lung cancer is still very limited but there are major expectations and many solutions are awaited in the coming years.

DC homeostasis in hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation is an important experimental tool and therapeutic modality. Its efficacy and toxicity are both linked to a GvH reaction that is initiated by donor T cells recognizing recipient APC, of which DC are the most potent. In most tissues recipient DC are replaced after transplantation because they turnover rapidly from BM-derived precursors. However, in a number of sites, notably the skin, recipient DC may persist and even self-renew for many months after transplantation. Understanding the homeostasis of different APC populations and how they are related to the induction of alloreactivity may help to improve the therapeutic benefit of transplantation.