Acute hypersensitivity pneumonitis in a paint quality controller : a case report

Introduction: Isocyanates are sensitizing chemicals used in various industries such as polyurethane foam production or paint-related purposes. Acting as haptens recognized by T-lymphocytes, they can cause allergic asthma and rarely hypersensitivity pneumonitis (HP). We aim to present a case report of acute HP due to hexamethylene diisocyanate (HDI) in a paint quality controller, a profession not generally considered at a high risk for work-related Isocyanates exposure. Case report: A 30-yr-old otherwise healthy female, light smoker working as a paint quality controller developed shortness of breath, malaise, sweating and chills at workplace six hours after handling a HDI-based hardener. Upon admission to emergency department, symptoms had progressed to severe respiratory failure. HR computer tomography (HRCT) showed bilateral ground-glass attenuation without pleural effusion. Rapid clinical and radiological improvement occurred under facial oxygen supply and systemic steroid therapy. Occupational medicine investigations revealed regular handling of HDI using latex gloves without respiratory protection. Assessment at workplace showed insufficient air renewal (1.5 times per hour), inadequate local aspiration and HDI exposure at levels of 1-4.25 ppb/m3 (Swiss Occupation Exposure Limit 5 ppb/m3). Biological monitoring after identical work procedure executed by a co-worker showed HDI exposure (5.1 micrograms hexamethylene diamine/g creatinine). Resumption of work was disadvised because of the life-threatening event. Discussion: The diagnosis of occupational HP is highly supported by classical findings on imagery and typical symptoms occurring within approved latency interval, associated with rapid clinical improvement. Although neither broncho-alveolar lavage nor specific IgG diagnosis (en route) were performed during the acute episode, various blood tests managed to rule out evidence of an infection or autoimmune disease. Other causes of HP seem unlikely as the patient did not have any recurrence of symptoms since absence from work. Workplace evaluation provided significant information on HDI exposure and allowed substantial recommendations to diminish Isocyanate exposure for the 20 still healthy laboratory co-workers. Although the entryways (air or skin) and precise mechanism of toxicity remain unclear, the present case clearly shows that Isocyanates may trigger acute HP in susceptible workers in a profession not generally considered at a high risk.

Human Plasma-derived Polymeric IgA and IgM Antibodies Associate with Secretory Component to Yield Biologically Active Secretory-like Antibodies.

Immunotherapy with monoclonal and polyclonal immunoglobulin is successfully applied to improve many clinical conditions, including infection, autoimmune diseases, or immunodeficiency. Most immunoglobulin products, recombinant or plasma-derived, are based on IgG antibodies, whereas to date, the use of IgA for therapeutic application has remained anecdotal. In particular, purification or production of large quantities of secretory IgA (SIgA) for potential mucosal application has not been achieved. In this work, we sought to investigate whether polymeric IgA (pIgA) recovered from human plasma is able to associate with secretory component (SC) to generate SIgA-like molecules. We found that ∼15% of plasma pIgA carried J chain and displayed selective SC binding capacity either in a mixture with monomeric IgA (mIgA) or after purification. The recombinant SC associated covalently in a 1:1 stoichiometry with pIgA and with similar efficacy as colostrum-derived SC. In comparison with pIgA, the association with SC delayed degradation of SIgA by intestinal proteases. Similar results were obtained with plasma-derived IgM. In vitro, plasma-derived IgA and SIgA neutralized Shigella flexneri used as a model pathogen, resulting in a delay of bacteria-induced damage targeted to polarized Caco-2 cell monolayers. The sum of these novel data demonstrates that association of plasma-derived IgA or IgM with recombinant/colostrum-derived SC is feasible and yields SIgA- and SIgM-like molecules with similar biochemical and functional characteristics as mucosa-derived immunoglobulins.

Is there a role for autoimmunity in immune protection against malaria?

Much remains to be known about the mechanisms involved in protective immunity against malaria and the way it is acquired. This is probably the reason why, in spite of so much progress, it has not yet been possible to develop an anti-malaria vaccine able to induce parasite specific antibodies (Ab) and/or T-cells. It has been considered in the early 80s that the induction of efficient protection against the blood stage forms of Plasmodium falciparum would not be possible without simultaneously eliciting an autoimmune (AI) response against erythrocytes, even at the price of inducing an AI pathology. Despite the description of the reciprocal relationship, i.e. the protective effect of malaria on the development of AI diseases - demonstrated since 1970 - no effort has been made to verify the possible involvement of the AI response in protection against malaria. With this end in view - and in the light of the knowledge acquired in autoimmunity and the existence of the so called "natural" (not associated with pathology) autoantibodies - we propose to examine the hypothesis that the participation of the AI response (not necessarily restricted to autologous erythrocyte antigens) in the immune protection against malaria is possible or even necessary.

Desenvolupament d’un nou model murí humanitzat de pemfigoide ampul•lar obtingut a partir de cèl•lules mare humanes fol·liculars

Resum: El pemfigoid ampul•lar és una malaltia cutània autoimmune. La majoria dels pacients presenten autoanticossos contra proteïnes de la membrana basal de la pell, concretament en contra de la col·làgena XVII, específicament envers el epítop immunodominant, l’NC16A. La patogenicitat dels anticossos ha estat demostrada mitjançant experiments in vitro i in vivo. L’escassa homologia existent entre l’NC16A i el seu homòleg murí (NC14A), ha dificultat l’el·laboració de models animals d’aquesta malaltia. En aquest treball demostrem que el sèrum de pacients amb pemfigoid ampul•lar produeix separació dermo-epidèrmica en pell de ratolí humanitzada obtinguda a partir de cèl•lules mare humanes del provinents fol·licle pil·lós

Evaluation of an enzyme immunoassay for hepatitis C virus antibody detection using a recombinant protein derived from the core region of hepatitis C virus genome

This study was undertaken to evaluate an enzyme immunoassay (EIA) for hepatitis C virus antibody detection (anti-HCV), using just one antigen. Anti-HCV EIA was designed to detect anti-HCV IgG using on the solid-phase a recombinant C22 antigen localized at the N-terminal end of the core region of HCV genome, produced by BioMérieux. The serum samples diluted in phosphate buffer saline were added to wells coated with the C22, and incubated. After washings, the wells were loaded with conjugated anti-IgG, and read in a microtiter plate reader (492 nm). Serum samples of 145 patients were divided in two groups: a control group of 39 patients with non-C hepatitis (10 acute hepatitis A, 10 acute hepatitis B, 9 chronic hepatitis B, and 10 autoimmune hepatitis) and a study group consisting of 106 patients with chronic HCV hepatitis. In the study group all patients had anti-HCV detected by a commercially available EIA (Abbott®), specific for HCV structural and nonstructural polypeptides, alanine aminotransferase elevation or positive serum HCV-RNA detected by nested-PCR. They also had a liver biopsy compatible with chronic hepatitis. The test was positive in 101 of the 106 (95%) sera from patients in the study group and negative in 38 of the 39 (97%) sera from those in the control group, showing an accuracy of 96%. According to these results, our EIA could be used to detect anti-HCV in the serum of patients infected with hepatitis C virus.

Relevance of biallelic versus monoallelic TNFRSF13B mutations in distinguishing disease-causing from risk-increasing TNFRSF13B variants in antibody deficiency syndromes.

TNFRSF13B encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), a B cell- specific tumor necrosis factor (TNF) receptor superfamily member. Both biallelic and monoallelic TNFRSF13B mutations were identified in patients with common variable immunodeficiency disorders. The genetic complexity and variable clinical presentation of TACI deficiency prompted us to evaluate the genetic, immunologic, and clinical condition in 50 individuals with TNFRSF13B alterations, following screening of 564 unrelated patients with hypogammaglobulinemia. We identified 13 new sequence variants. The most frequent TNFRSF13B variants (C104R and A181E; n=39; 6.9%) were also present in a heterozygous state in 2% of 675 controls. All patients with biallelic mutations had hypogammaglobulinemia and nearly all showed impaired binding to a proliferation-inducing ligand (APRIL). However, the majority (n=41; 82%) of the pa-tients carried monoallelic changes in TNFRSF13B. Presence of a heterozygous mutation was associated with antibody deficiency (P< .001, relative risk 3.6). Heterozygosity for the most common mutation, C104R, was associated with disease (P< .001, relative risk 4.2). Furthermore, heterozygosity for C104R was associated with low numbers of IgD(-)CD27(+) B cells (P= .019), benign lymphoproliferation (P< .001), and autoimmune complications (P= .001). These associations indicate that C104R heterozygosity increases the risk for common variable immunodeficiency disorders and influences clinical presentation.

Natural immunoglobulins (contribution to a debate on biomedical education)

Immunology has contributed to biomedical education in many important ways since the creation of scientific medicine in the last quarter of the 19th century. Today, immunology is a major area of biomedical research. Nevertheless, there are many basic problems unresolved in immunological activities and phenomena. Solving these problems is probably necessary to devise predictable and safe ways to produce new vaccines, treat allergy and autoimmune diseases and perform safe transplants. This challenge involves not only technical developments but also changes in attitude, of which the most fundamental is to abandon the traditional stimulus-response perspective in favor of more "systemic" views. Describing immunological activities as the operation of a complex multiconnected network, raises biological and epistemological issues not usually dealt with in biomedical education. Here we point to one example of systemic approaches. A new form of immunoblot (Panama blot), by which the reaction of natural immunoglobulins with complex protein mixtures may be analyzed by a special software and multivariate statistics, has been recently used to characterize human autoimmune diseases. Our preliminary data show that Panama blots can also be used to characterize global (systemic) immunogical changes in chronic human parasitic diseases, such as malaria and schistosomiasis mansoni, that correlate with the clinical status.

Histone deacetylase inhibitors impair innate immune responses

SUMMARYThe innate immune system plays a central role in host defenses against invading pathogens. Innate immune cells sense the presence of pathogens through pattern recognition receptors that trigger intracellular signaling, leading to the production of pro-inflammatory mediators like cytokines, which shape innate and adaptive immune responses. Both by excess and by default inflammation may be detrimental to the host. Indeed, severe sepsis and septic shock are lethal complications of infections characterized by a dysregulated inflammatory response.In recent years, members of the superfamily of histone deacetylases have been the focus of great interest. In mammals, histone deacetylases are broadly classified into two main subfamilies comprising histone deacetylases 1-11 (HDAC1-11) and sirtuins 1-7 (SIRT1-7). These enzymes influence gene expression by deacetylating histones and numerous non-histone proteins. Histone deacetylases have been involved in the development of oncologic, metabolic, cardiovascular, neurodegenerative and autoimmune diseases. Pharmacological modulators of histone deacetylase activity, principally inhibitors, have been developed for the treatment of cancer and metabolic diseases. When we initiated this project, several studies suggested that inhibitors of HDAC 1-11 have anti-inflammatory activity. Yet, their influence on innate immune responses was largely uncharacterized. The present study was initiated to fill in this gap.In the first part of this work, we report the first comprehensive study of the effects of HDAC 1- 11 inhibitors on innate immune responses in vitro and in vivo. Strikingly, expression studies revealed that HDAC1-11 inhibitors act essentially as negative regulators of basal and microbial product- induced expression of critical immune receptors and antimicrobial products by mouse and human innate immune cells like macrophages and dendritic cells. Furthermore, we describe a new molecular mechanism whereby HDAC1-11 inhibitors repress pro-inflammatory cytokine expression through the induction of the expression and the activity of the transcriptional repressor Μί-2β. HDAC1-11 inhibitors also impair the potential of macrophages to engulf and kill bacteria. Finally, mice treated with an HDAC inhibitor are more susceptible to non-severe bacterial and fungal infection, but are protected against toxic and septic shock. Altogether these data support the concept that HDAC 1-11 inhibitors have potent anti-inflammatory and immunomodulatory activities in vitro and in vivo.Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that plays a central role in innate immune responses, cell proliferation and oncogenesis. In the second part of this manuscript, we demonstrate that HDAC1-11 inhibitors inhibit MIF expression in vitro and in vivo and describe a novel molecular mechanism accounting for these effects. We propose that inhibition of MIF expression by HDAC 1-11 inhibitors may contribute to the antitumorigenic and anti-inflammatory effects of these drugs.NAD+ is an essential cofactor of sirtuins activity and one of the major sources of energy within the cells. Therefore, sirtuins link deacetylation to NAD+ metabolism and energy status. In the last part of this thesis, we report preliminary results indicating that a pharmacological inhibitor of SIRT1-2 drastically decreases pro-inflammatory cytokine production (RNA and protein) and interferes with MAP kinase intracellular signal transduction pathway in macrophages. Moreover, administration of the SIRT1-2 inhibitor protects mice from lethal endotoxic shock and septic shock.Overall, our studies demonstrate that inhibitors of HDAC1-11 and sirtuins are powerful anti-inflammatory molecules. Given their profound negative impact on the host antimicrobial defence response, these inhibitors might increase the susceptibility to opportunistic infections, especially in immunocompromised cancer patients. Yet, these inhibitors might be useful to control the inflammatory response in severely ill septic patients or in patients suffering from chronic inflammatory diseases.

Dépendances [Addiction]

The 2009 news in medicine regarding dependence confirm the bio-psycho-social field of addiction medicine and psychiatry. First a statement is made about the risk of cardiac arythmy in opioid substitution treatments. Then a review of the treatment of C hepatitis shows its importance in an addicted population. In the field of cognitive neuroscience, progress has been made in the knowledge of "craving" and of its endophenotypical components. Electronic medias related disorders are on the border of addiction: a case study is exploring this new domain. At last, recent datas are presented on the relationship between cannabis and psychosis. Les nouveautés en médecine 2009 concernant les dépendances confirment l'étendue du champ bio-psychosocial de la médecine et de la psychiatrie de l'addiction. Tout d'abord un point de situation est fait sur le risque d'arythmie cardiaque dans les traitements de substitution opiacée. Puis une revue de l'actualité du traitement de l'hépatite C dans la toxicodépendance en montre la pertinence. Sur le plan de la recherche plus fondamentale, les neurosciences cognitives progressent dans l'approche de la nature du craving et de ses composantes endophénotypiques. Les troubles liés aux médias électroniques illustrent les frontières de l'addiction : une étude de cas vient en explorer le contenu. Enfin, des données récentes sur les rapports entre cannabis et psychoses sont présentées.

SAMHD1 is mutated recurrently in chronic lymphocytic leukemia and is involved in response to DNA damage.

SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase and a nuclease that restricts HIV-1 in noncycling cells. Germ-line mutations in SAMHD1 have been described in patients with Aicardi-Goutières syndrome (AGS), a congenital autoimmune disease. In a previous longitudinal whole genome sequencing study of chronic lymphocytic leukemia (CLL), we revealed a SAMHD1 mutation as a potential founding event. Here, we describe an AGS patient carrying a pathogenic germ-line SAMHD1 mutation who developed CLL at 24 years of age. Using clinical trial samples, we show that acquired SAMHD1 mutations are associated with high variant allele frequency and reduced SAMHD1 expression and occur in 11% of relapsed/refractory CLL patients. We provide evidence that SAMHD1 regulates cell proliferation and survival and engages in specific protein interactions in response to DNA damage. We propose that SAMHD1 may have a function in DNA repair and that the presence of SAMHD1 mutations in CLL promotes leukemia development.

Destruction of conditional insulinoma cell lines in NOD mice: a role for autoimmunity.

AIMS/HYPOTHESIS: betaTC-tet (H2(k)) is a conditional insulinoma cell line derived from transgenic mice expressing a tetracycline-regulated oncogene. Transgenic expression of several proteins implicated in the apoptotic pathways increase the resistance of betaTC-tet cells in vitro. We tested in vivo the sensitivity of the cells to rejection and the protective effect of genetic alterations in NOD mice. METHODS: betaTC-tet cells and genetically engineered lines expressing Bcl-2 (CDM3D), a dominant negative mutant of MyD88 or SOCS-1 were transplanted in diabetic female NOD mice or in male NOD mice with diabetes induced by high-dose streptozotocin. Survival of functional cell grafts in NOD-scid mice was also analyzed after transfer of splenocytes from diabetic NOD mice. Autoreactive T-cell hybridomas and splenocytes from diabetic NOD mice were stimulated by betaTC-tet cells. RESULTS: betaTC-tet cells and genetically engineered cell lines were all similarly rejected in diabetic NOD mice and in NOD-scid mice after splenocyte transfer. In 3- to 6-week-old male NOD mice treated with high-dose streptozotocin, the cells temporarily survived, in contrast with C57BL/6 mice treated with high-dose streptozotocin (indefinite survival) and untreated 3- to 6-week-old male NOD mice (rejection). The protective effect of high-dose streptozotocin was lost in older male NOD mice. betaTC-tet cells did not stimulate autoreactive T-cell hybridomas, but induced IL-2 secretion by splenocytes from diabetic NOD mice. CONCLUSION/INTERPRETATION: The autoimmune process seems to play an important role in the destruction of betaTC-tet cells in NOD mice. Genetic manipulations intended at increasing the resistance of beta cells were inefficient. Similar approaches should be tested in vivo as well as in vitro. High dose streptozotocin influences immune rejection and should be used with caution.

Immunodéficience commune variable: ce qu'il faut savoir [Common variable immune deficiency: what you need to know].

Common variable immune deficiency is the most frequent primary immune deficiency, characterized mainly by a disorder of B lymphocytes differentiation and a deficit in immunoglobulins. The clinical manifestations include recurrent infections, non-infectious lung and digestive involvements, autoimmune diseases, and an increased susceptibility to cancers. Recent breakthroughs have been made in the understanding of some genetic mechanisms of the disease. Replacement therapy with intravenous immunoglobulins remains the treatment of choice, which allows significant improvement in the survival and quality of life. However progress should be made in the understanding of the pathophysiology and in the early detection of this disease, since a delay in the diagnosis may have harmful consequences in terms of morbidity and mortality.

Protease-activated receptor 2 signalling promotes dendritic cell antigen transport and T-cell activation in vivo.

Deficiency of protease-activated receptor-2 (PAR2) modulates inflammation in several models of inflammatory and autoimmune disease, although the underlying mechanism(s) are not understood. PAR2 is expressed on endothelial and immune cells, and is implicated in dendritic cell (DC) differentiation. We investigated in vivo the impact of PAR2 activation on DCs and T cells in PAR2 wild-type (WT) and knockout (KO) mice using a specific PAR2 agonist peptide (AP2). PAR2 activation significantly increased the frequency of mature CD11c(high) DCs in draining lymph nodes 24 hr after AP2 administration. Furthermore, these DCs exhibited increased expression of major histocompatibility complex (MHC) class II and CD86. A significant increase in activated (CD44(+) CD62(-)) CD4(+) and CD8(+) T-cell frequencies was also observed in draining lymph nodes 48 hr after AP2 injection. No detectable change in DC or T-cell activation profiles was observed in the spleen. The influence of PAR2 signalling on antigen transport to draining lymph nodes was assessed in the context of delayed-type hypersensitivity. PAR2 WT mice that were sensitized by skin-painting with fluorescein isothiocyanate (FITC) to induce delayed-type hypersensitivity possessed elevated proportion of FITC(+) DCs in draining lymph nodes 24 hr after FITC painting when compared with PAR2 KO mice (0.95% versus 0.47% of total lymph node cells). Collectively, these results demonstrate that PAR2 signalling promotes DC trafficking to the lymph nodes and subsequent T-cell activation, and thus provides an explanation for the pro-inflammatory effect of PAR2 in animal models of inflammation.

Estudis estructurals dels canvis conformacionals de les E3 ubiquitin lligases per RMN

L'estudi a nivell molecular de la ruta de senyalització activada per TGF-B té un impacte notable en el panorama actual donada la seva implicació en processos autoimmunitaris i carcinogènics. D'altra banda, l'elucidació a nivell estructural dels mecanismes moleculars que permeten a les ubiquitin lligases de tipus E3 marcar específicament llurs dianes per a la degradació proteosòmica - entre d'altres - resulta fonamental donada la seva importància pel que fa al control sobre el turnover proteic a nivell intracel•lular. En aquest projecte es pretén elucidar els mecanismes d'activació i catlàlisi de les ubiquitin lligases E3 tipus HECT Smurf1 i Nedd4L al mateix temps que se n'estudia la implicació en la regulació dels agents missatgers de la ruta del TGF-B. Així, la tasca es divideix en tres sub-projectes els quals se centren en a) l'estudi de la interacció d'aquestes lligases amb llurs dianes; b) l'elucidació del mecanisme d'activació i c) del de catàlisi d'aquests enzims. Per tal d'assolir aquests objectius ens servim principalment dels avantatges que ens aporta la Ressonància Magnètica Nuclear i altres tècniques biofísiques, principalment la ITC. Durant el temps que he gaudit de la beca FI, m'he centrat principalment en la preparació de pèptids per SPPS, llur purificació per HPLC i caracterització per MS i RMN. Aquests pèptids representen diferents patrons de fosforilació de certes dianes de les lligases esmentades, de manera que han estat emprats per a l'estudi d'interaccions proteïna-proteïna per ITC i RMN. M'he iniciat doncs en l'ús d'aquestes tècniques. D'altra banda, també he preparat mostres protèiques mitjançant l'ús de sistemes d'expressió bacterians basats en E.coli, incloent l'amplificació i clonació del gen que codifica per la proteïna d'interés així com la seva expressió, purificació i caracterització per MS i RMN.

Hepatitis autoimnune. Diagnòstic, característiques clíniques i resposta al tractament

La hepatitis autoimmune (HAI) és una patologia inflamatòria crónica hepàtica, progressiva i d’origen desconegut d’àmplia variabilitat clínica. S’estudiaren 40 casos (edad mitjana 50.8 anys, 82,5% dones). Al nostre medi la majoria de casos d’HAI són de tipus 1, el 40% debuten en forma d’hepatitis aguda i tenen una malaltia autoimmune associada. El 60% van rebre incialment monoteràpia amb corticoides i el 32,5% associats a azatioprina. Al 94% s’aconsegueix la remissió independentment de la pauta terapèutica i és més freqüent si l’AST està augmentada.