Echovirus meningoencephalitis in X-linked hypogammaglobulinemia.

Echovirus meningoencephalitis and polymyositis are classical complications of X-linked agammaglobulinemia (1). The treatment of meningoencephalitis is troublesome since intravenous (2), intrathecal (3) and intraventricular (4) administration of gammaglobulins have been reported successful, but failure also occurred in some cases (5). We report our experience of high dose intravenous treatment.

Both CD4+ and CD8+ lymphocytes participate in the IFN-y response to filamentous hemagglutinin from Bordetella pertussis in infants, children and adults

Infant CD4+ T-cell responses to bacterial infections or vaccines have been extensively studied, whereas studies on CD8 + T-cell responses focused mainly on viral and intracellular parasite infections. Here we investigated CD8 + T-cell responses upon Bordetella pertussis infection in infants, children, and adults and pertussis vaccination in infants. Filamentous hemagglutinin-specific IFN-γ secretion by circulating lymphocytes was blocked by anti-MHC-I or -MHC-II antibodies, suggesting that CD4 + and CD8 + T lymphocytes are involved in IFN-γ production. Flow cytometry analyses confirmed that both cell types synthesized antigen-specific IFN-γ, although CD4 + lymphocytes were the major source of this cytokine. IFN-γ synthesis by CD8 + cells was CD4 + T cell dependent, as evidenced by selective depletion experiments. Furthermore, IFN-γ synthesis by CD4 + cells was sometimes inhibited by CD8 + lymphocytes, suggesting the presence of CD8 + regulatory T cells. The role of this dual IFN-γ secretion by CD4 + and CD8 + T lymphocytes in pertussis remains to be investigated. © 2012 Violette Dirix et al.

Développement ontogénique des lymphocytes B chez la souris et inactivation de jeunes lymphocytes B par un antigène

info:eu-repo/semantics/published

Idiotypic networks and self-recognition in the immune system.

Journal Article

Evidence for distinct dehydrogenase and isomerase sites within a single 3β-hydroxysteroid dehydrogenase/5-ene-4-ene isomerase protein

Complementary DNA encoding human 3β-hydroxysteroid dehydrogenase/5-ene-4-ene isomerase (30-HSD) has been expressed in transfected GH4C1 with use of the cytomegalovirus promoter. The activity of the expressed protein clearly shows that both dehydrogenase and isomerase enzymatic activities are present within a single protein. However, such findings do not indicate whether the two activities reside within one or two closely related catalytic sites. With use of [3H]-5-androstenedione, the intermediate compound in dehydroepiandrosterone (DHEA) transformation into 4-androstenedione by 3β-HSD, the present study shows that 4MA (N,N-diethyl-4-rnethyl-3-oxo-4-aza-5α-androstane-17β-carboxamide) and its analogues inhibit DHEA oxidation competitively while they exert a noncompetitive inhibition of the isomerization of 5-androstenedione to 4-androstenedione with an approximately 1000-fold higher Ki value. The present results thus strongly suggest that dehydrogenase and isomerase activities are present at separate sites on the 3β-HSD protein. In addition, using 5α-dihydrotestosterone (DHT) and 5α-androstane-3β,17β-diol as substrates for dehydrogenase activity only, we have found that dehydrogenase activity is reversibly and competitively inhibited by 4MA. Such data suggest that the irreversible step in the transformation of DHEA to 4-androstenedione is due to a separate site possessing isomerase activity that converts the 5-ene-3-keto to a much more stable 4-ene-3-keto configuration. © 1991 American Chemical Society.

Modulation of the complement system in monocytes contributes to tuberculosis-associated immune reconstitution inflammatory syndrome.

Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a common complication in HIV-TB co-infected patients receiving combined antiretroviral therapy (cART). This study investigated a putative contribution of monocytes to the development of TB-IRIS.

The role of monocytes in the development of Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome

info:eu-repo/semantics/published

The radiation-inducible pE9 promoter driving inducible nitric oxide synthase radiosensitizes hypoxic tumour cells to radiation

Driving high-level transgene expression in a tumour-specific manner remains a key requirement in the development of cancer gene therapy. We have previously demonstrated the strong anticancer effects of generating abnormally high levels of intracellular NO• following the overexpression of the inducible nitric oxide synthase (iNOS) gene. Much of this work has focused on utilizing exogenously activated promoters, which have been primarily induced using X-ray radiation. Here we further examine the potential of the pE9 promoter, comprising a combination of nine CArG radio-responsive elements, to drive the iNOS transgene. Effects of X-ray irradiation on promoter activity were compared in vitro under normoxic conditions and various degrees of hypoxia. The pE9 promoter generated high-level transgene expression, comparable with that achieved using the constitutively driven cytomegalovirus promoter. Furthermore, the radio-resistance of radiation-induced fibrosarcoma-1 (RIF-1) mouse sarcoma cells exposed to 0.1 and 0.01% O2 was effectively eliminated following transfection with the pE9/iNOS construct. Significant inhibition of tumour growth was also observed in vivo following direct intratumoural injection of the pE9/iNOS construct compared to empty vector alone (P<0.001) or to a single radiation dose of 10?Gy (P<0.01). The combination of both therapies resulted in a significant 4.25 day growth delay compared to the gene therapy treatment alone (P<0.001). In summary, we have demonstrated the potential of the pE9/iNOS construct for reducing radio-resistance conferred by tumour cell hypoxia in vitro and in vivo, with greater tumour growth delay observed following the treatment with the gene therapy construct as compared with radiotherapy alone.

Adrenomedullin Gene Delivery is Cardio-protective in a Model of Chronic Nitric Oxide Deficiency Combining Pressure Overload, Oxidative Stress and Cardiomyocyte Hypertrophy

BACKGROUND/AIMS:
Chronic inhibition of nitric oxide (NO) synthesis is associated with hypertension, myocardial ischemia, oxidative stress and hypertrophy; expression of the vasodilator peptide, adrenomedullin (AM) and its receptors is augmented in cardiomyocytes, indicating that the myocardial AM system may be activated in response to pressure loading and ischemic insult to serve a counter-regulatory, cardio-protective role. The study examined the hypothesis that oxidative stress and hypertrophic remodeling in NO-deficient cardiomyocytes are attenuated by adenoviral vector-mediated delivery of the human adrenomedullin (hAM) gene in vivo.

METHODS:
The NO synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 15mg . kg(-1) . day(-1)) was given to rats for 4 weeks following systemic administration via the tail vein of a single injection of either adenovirus harbouring hAM cDNA under the control of the cytomegalovirus promoter-enhancer (Ad.CMV-hAM-4F2), or for comparison, adenovirus alone (Ad.Null) or saline. Cardiomyocytes were subsequently isolated for assessment of the influence of each intervention on parameters of oxidative stress and hypertrophic remodelling.

RESULTS: Cardiomyocyte expression of the transgene persisted for > or =4 weeks following systemic administration of adenoviral vector. In L-NAME treated rats, relative to Ad.Null or saline administration, Ad.CMV-hAM-4F2 (i) reduced augmented cardiomyocyte membrane protein oxidation and mRNA expression of pro-oxidant (p22phox) and anti-oxidant (SOD-3, GPx) genes; (ii) attenuated increased cardiomyocyte width and mRNA expression of hypertrophic (sk-alpha-actin) and cardio-endocrine (ANP) genes; (iii) did not attenuate hypertension.

CONCLUSIONS: Adenoviral vector mediated delivery of hAM resulted in attenuation of myocardial oxidative stress and hypertrophic remodelling in the absence of blood pressure reduction in this model of chronic NO-deficiency. These findings are consistent with a direct cardio-protective action in the myocardium of locally-derived hAM which is not dependant on NO generation.

Demarcation laser therapy in the management of macular-sparing persistent subretinal fluid after scleral buckling procedures

Background: Persistent or recurrent macular-sparing subretinal fluid (SRF) can sometimes occur following scleral buckling procedures. Observation and reoperation have been used in the management of such cases. Demarcation laser therapy (DLT) has been used to treat macular-sparing retinal detachments in the context of cytomegalovirus retinitis and as primary treatment for selected rhegmatogenous retinal detachments. There are, however, scarce data in the literature regarding its use following primary scleral buckling procedures. The current study explores the use of DLT under the latter circumstances. Methods: The medical records of all consecutive patients with persistent SRF sparing the macula following primary rhegmatogenous retinal detachment repair using a scleral buckling procedure were retrospectively reviewed. Only those patients in whom the breaks were localised to the area of indentation and, thus, seemed to be well supported by the buckle were included. Demographics, clinical characteristics of the retinal detachment prior to scleral buckling, extension of the residual SRF observed postoperatively, details of the laser procedure, anatomical and functional outcomes and complications were evaluated. Results: Seven patients, all females, with a mean age of 47.9 years (range: 20-81) were included in the study. The retinal detachments were superior (n=3), inferior (n=3) and subtotal, affecting both superior and inferior retina (n=1). Scleral buckling procedures were used to treat the retinal detachments in all cases. Following demarcation laser therapy, the area of SRF remained stable in two patients, and flattened in four. In one patient, extension of SRF occurred requiring further surgery. Conclusions: Demarcation laser therapy appears to be a reasonable option in the management of patients with persistent or recurrent SRF sparing the macula following scleral buckling surgery. © Springer-Verlag 2006.

Campath-1G in vivo confers a low incidence of graft-versus-host disease associated with a high incidence of mixed chimaerism after bone marrow transplantation for severe aplastic anaemia using HLA-identical sibling donors

We have evaluated the effect of in vivo Campath-1G on engraftment and GVHD in 23 patients with severe aplastic anaemia transplanted from HLA-identical sibling donors. In 14 patients Campath 1g was given pre-transplant for up to 9 days in an attempt to overcome graft rejection (group 1). In nine patients Campath-1G was given pre-transplant, but also continued post-transplant until day +5 to reduce GVHD (group 2). There were three patients with late graft failure in group I following initial neutrophil engraftment, and four cases of grade II+ GVHD. In group II, two patients had early graft failure (no take), and there were no cases of acute GVHD out of seven evaluable patients. One patient in group I developed chronic GVHD of the liver, and two patients (one in each group) had transient localised chronic GVHD. PCR of short tandem repeats was used to evaluate chimaeric status in 13 patients. Of 11 patients with initial neutrophil engraftment, only one had 100% donor haemopoiesis at all times. The remaining patients had either transient mixed chimaerism or persistence of recipient (< 20%) cells. We conclude that in vivo Campath-1G is associated with a high incidence of mixed chimaerism which tips the balance away from GVHD but towards graft rejection.

Patterns of hematopoietic chimerism following bone marrow transplantation for childhood acute lymphoblastic leukemia from volunteer unrelated donors

Hematopoietic chimerism was analyzed in serial bone marrow samples taken from 28 children following T-cell depleted unrelated donor bone marrow transplants (UD BMT) for acute lymphoblastic leukemia (ALL). Chimeric status was determined by polymerase chain reaction (PCR) of simple tandem repeat (STR) sequences (maximal sensitivity, 0.1%). At least two serial samples were examined in 23 patients. Of these, two had evidence of complete donor engraftment at all times and eight showed stable low level mixed chimerism (MC) (<1% recipient hematopoiesis). All 10 of these patients remain in remission with a minimum follow-up of 24 months. By contrast, 13 patients demonstrated a progressive return of recipient hematopoiesis. Five of these relapsed (4 to 9 months post BMT), one died of cytomegalovirus pneumonitis and seven remain in remission with a minimum follow-up of 24 months. Five children were excluded from serial analysis as two serial samples were not collected before either relapse (3) or graft rejection (2). We conclude that as with sibling transplants, ex vivo T depleted UD BMT in children with ALL is associated with a high incidence of MC. Stable donor engraftment and low level MC always correlated with continued remission. However, detection of a progressive return of recipient cells did not universally correlate with relapse, but highlighted those patients at greatest risk. Serial chimerism analysis by PCR of STRs provides a rapid and simple screening technique for the detection of relapse and the identification of patients with progressive MC who might benefit from detailed molecular analysis for minimal residual disease following matched volunteer UD BMT for childhood ALL.

Application of the pMHC Array to Characterise Tumour Antigen Specific T Cell Populations in Leukaemia Patients at Disease Diagnosis

Immunotherapy treatments for cancer are becoming increasingly successful, however to further improve our understanding of the T-cell recognition involved in effective responses and to encourage moves towards the development of personalised treatments for leukaemia immunotherapy, precise antigenic targets in individual patients have been identified. Cellular arrays using peptide-MHC (pMHC) tetramers allow the simultaneous detection of different antigen specific T-cell populations naturally circulating in patients and normal donors. We have developed the pMHC array to detect CD8+ T-cell populations in leukaemia patients that recognise epitopes within viral antigens (cytomegalovirus (CMV) and influenza (Flu)) and leukaemia antigens (including Per Arnt Sim domain 1 (PASD1), MelanA, Wilms' Tumour (WT1) and tyrosinase). We show that the pMHC array is at least as sensitive as flow cytometry and has the potential to rapidly identify more than 40 specific T-cell populations in a small sample of T-cells (0.8-1.4 x 106). Fourteen of the twenty-six acute myeloid leukaemia (AML) patients analysed had T cells that recognised tumour antigen epitopes, and eight of these recognised PASD1 epitopes. Other tumour epitopes recognised were MelanA (n = 3), tyrosinase (n = 3) and WT1126-134 (n = 1). One of the seven acute lymphocytic leukaemia (ALL) patients analysed had T cells that recognised the MUC1950-958 epitope. In the future the pMHC array may be used provide point of care T-cell analyses, predict patient response to conventional therapy and direct personalised immunotherapy for patients.

Potentiel des liposomes pour l'injection intravitréenne de molécules thérapeutiques [Potential of liposomes for the intravitreal injection of therapeutic molecules].

Intravitreal administration has been widely used since 20 years and has been shown to improve the treatment of diseases of the posterior segment of the eye with infectious origin or in edematous maculopathies. This route of administration allows to achieve high concentration of drug in the vitreous and avoids the problems resulting from systemic administration. However, two basic problems limit the use of intravitreal therapy. Many drugs are rapidly cleared from the vitreous humor; therefore, to reach and to maintain effective therapy repeated injections are necessary. Repeated intravitreal injections increase the risk of endophthalmitis, damage to lens, retinal detachment. Moreover, some drugs provoke a local toxicity at their effective dose inducing side-effects and possible retinal lesions. In this context, the development and the use of new drug delivery systems for intravitreal administration are necessary to treat chronic ocular diseases. Among them, particulate systems such as liposomes have been widely studied. Liposomes are easily injectable and permit to reduce the toxicity and to increase the residence time of several drugs in the eye. They are also able to protect in vivo poorly-stable molecules from degradation such as peptides and nucleic acids. Some promising results have been obtained for the treatment of retinitis induced by cytomegalovirus in human and more recently for the treatment of uveitis in animal. Finally, the fate of liposomes in ocular tissues and fluids after their injection into the vitreous and their elimination routes begin to be more known.