Type III hereditary angio-oedema: clinical and biological features in a French cohort.

BACKGROUND: Hereditary angio-oedema (HAE) has been associated with C1inhibitor deficiency. The first cases of type III HAE were described in patients with normal C1Inh antigenic protein level and function and normal C4 levels in 2000. This finding has been reported mostly in women with a family history and may be influenced by exogenous oestrogen exposure. OBJECTIVES: The purpose of this article is to describe the clinical, biological and genetic characteristics of a French population suffering from type III HAE. PATIENTS AND METHODS: We conducted a retrospective analysis of angio-oedema (AE) cases seen in the National Reference Centre of AE between 2000 and 2009. RESULTS: We found 26 patients (from 15 unrelated families) with type III HAE. All but four were women and presented with typical AE attacks, exacerbated by pregnancy or oral contraceptives containing oestrogens (OC). We also found that 54.5% of women were worsened with oestrogen and 23% were oestrogen dependent. All patients improved on long-term prophylactic tranexamic acid treatment; some acute attacks improved with C1Inh concentrate infusion. All of the patients had normal C1Inh and C4 levels. C1Inh function was also normal, except in women receiving OC or during a pregnancy: transient, moderately low levels (32-74% of the normal range) were found in 18 patients tested (67%). No SERPING1 gene mutation was found. Six patients from three unrelated families were heterozygous for an F12 gene variant. CONCLUSION: Diagnosis of type III HAE should be based on clinical (typical attacks, often hormonally influenced), laboratory (normal C1Inh antigenic protein) and genetic (F12 gene mutation) evidence.

The effect of metal imbalances on scrapie neurodegeneration.

Environmental exposure to metal appears to enhance susceptibility to Transmissible Spongiform Encephalopathies (TSEs); however, published data are not conclusive. The current study focuses on assessing the effects of copper depletion and/or manganese enhancement in the diet on susceptibility to Scrapie and this disease progression. The degree of spongiosis was the highest in the animals that received a copper- depleted diet. These observations suggest that this diet contributes to the Scrapie lesions and to the worsening of the condition in animals that have been inoculated with Scrapie. The highest intensities of GFAP immunostaining were also associated with the copper- depleted diet. Dietary supplementation with manganese had a negative effect on neuronal counts. In conclusion, this study demonstrates that certain environmental factors may aggravate neuropathological Scrapie lesions. This is consistent with reports from other neurodegenerative diseases where some metalloenzymes play a pivotal protector role against the oxidative stress associated with pathogenesis.

Effect of the dimethoate administration on a Scrapie murine model.

Some authors have associated organophosphate compounds with susceptibility to transmissible spongiform encephalopathy (TSE) and even with the origin of this group of diseases. Nevertheless, the actual role played by these compounds still remains unclear. The aim of this study was to assess the effect of oral exposure to dimethoate (DMT) on the development of Scrapie using a genetically modified murine model. A total of 70 C57BL/6 mice over-expressing the PrP gene (Tg20) were included in the present study. A portion of the mice were intraperitoneally inoculated, while the rest were maintained as non-infected controls. Animals from the treated group were exposed to dimethoate dissolved in drinking water from the beginning of the experiment. Variables of incubation period, spongiosis, PrPsc deposits, glial over-expression, neuronal loss, and amyloid plaques were assessed in all animals. According to the results, a treatment consisting of a daily 15 mg/kg dose of DMT for 5 weeks did not show any effect on any of the variables assessed. Although more exhaustive studies for assessing different doses and organic compounds are required, this finding constitutes an empirical study that rules out the possibility that this compound may have a predisposing effect on TSEs.

Can a second wave of new variant of the CJD be discarded in absence of observation of clinical non Met-Met cases?

BACKGROUND: Presently, all patients with clinical variant Creutzfeldt-Jakob disease in the United Kingdom have been Met-Met at codon 129 of the PrP gene. There is much worry about the possibility of a second wave of the epidemic in the 60% of the United Kingdom population which are not Met-Met. METHODS: A mathematical model of a putative United Kingdom variant Creutzfeldt-Jakob disease epidemic that could occur in non Met-Met is derived. The risk of infection is assumed to parallel the Met-Met risk which has been previously modelled. The reason for the present absence of clinical non Met-Met cases is assumed to be a longer incubation period in these subjects than in others. The incubation period is assumed to be lognormally distributed. The means and coefficients of variation compatible with the present absence of clinical cases are systematically searched. RESULTS: We show that the present absence of clinical cases of variant Creutzfeldt-Jakob disease in the Met-Val or Val-Val population can be compatible with a second wave only if the mean incubation period is more than 25 years. The best estimates of the size of the second wave are always below 250. A fraction of these cases however will never be observed, as they will die from other causes before the onset of the new variant. CONCLUSION: The mean incubation period values compatible with the absence of non Met-Met clinical cases that we found are not implausible, and the possibility of a second wave cannot yet be ruled out. However, should this second wave occur, it would be below 250 in the worst hypothesis.

Estimation of epidemic size and incubation time based on age characteristics of vCJD in the United Kingdom.

The size of the variant Creutzfeldt-Jakob Disease (vCJD) epidemic in the United Kingdom is a major public health concern and a subject of speculation. The cases are young (mean age = 28). Assuming that the risk of developing the disease in susceptible exposed subjects decreases exponentially with age after age 15, that all infections occurred between 1980 and 1989, and that the distribution of the incubation period is lognormal, we estimate that the mean duration of the incubation period is 16.7 years [95% confidence interval (CI): 12.4 to 23.2] and that the total number of cases will be 205 (upper limit of the 95% CI: 403).

Human FDC express PrPc in vivo and in vitro.

Prion diseases are fatal neurodegenerative disorders caused by accumulation of abnormal prion protein (protease-resistant prion, PrPres). PrPres accumulation is also detected in lymphoid organs after peripheral infection. Several studies suggest that follicular dendritic cells (FDC) could be the site of PrPres retention and amplification. Here we show that human follicular dendritic cells can express normal cellular prion protein (PrPc) both in situ and in vitro. When tonsillar cryosections were treated with anti-PrP antibody, the label was found on some very delicate cell extensions inside the lymphoid follicles, especially in the germinal centres. These extensions react with DRC1 antibody, used frequently to label FDC. Other structures labelled with anti-PrP antibody were the keratinocytes. To confirm the ability of FDC to synthesise PrPc, we isolated FDC by a non-enzymatic procedure and cultured them. By cytochemistry and flow cytometry it was clearly shown that FDC do produce PrPc.

Epithelial and endothelial expression of the green fluorescent protein reporter gene under the control of bovine prion protein (PrP) gene regulatory sequences in transgenic mice.

The expression of the cellular form of the prion protein (PrP(c)) gene is required for prion replication and neuroinvasion in transmissible spongiform encephalopathies. The identification of the cell types expressing PrP(c) is necessary to understanding how the agent replicates and spreads from peripheral sites to the central nervous system. To determine the nature of the cell types expressing PrP(c), a green fluorescent protein reporter gene was expressed in transgenic mice under the control of 6.9 kb of the bovine PrP gene regulatory sequences. It was shown that the bovine PrP gene is expressed as two populations of mRNA differing by alternative splicing of one 115-bp 5' untranslated exon in 17 different bovine tissues. The analysis of transgenic mice showed reporter gene expression in some cells that have been identified as expressing PrP, such as cerebellar Purkinje cells, lymphocytes, and keratinocytes. In addition, expression of green fluorescent protein was observed in the plexus of the enteric nervous system and in a restricted subset of cells not yet clearly identified as expressing PrP: the epithelial cells of the thymic medullary and the endothelial cells of both the mucosal capillaries of the intestine and the renal capillaries. These data provide valuable information on the distribution of PrP(c) at the cellular level and argue for roles of the epithelial and endothelial cells in the spread of infection from the periphery to the brain. Moreover, the transgenic mice described in this paper provide a model that will allow for the study of the transcriptional activity of the PrP gene promoter in response to scrapie infection.

Differential expression of cellular prion protein on human blood and tonsil lymphocytes.

BACKGROUND AND OBJECTIVE: The expression of cellular prion protein (PrPc) on the surface of peripheral lymphocytes has been previously reported, but little is known about its expression on lymphoid cells from secondary lymph organs. In this report, we compare the surface expression of PrPc on human blood lymphocytes and tonsil lymphocytes. DESIGN AND METHODS: This analysis was performed by cytometry on live lymphocytes isolated from healthy donors or from the tonsils of adults or children. RESULTS: Human peripheral lymphocytes and tonsillar lymphoid cells, but not erythrocytes or granulocytes, express PrPc at their surfaces. Interestingly, we found significantly less PrPc on freshly isolated tonsil lymphocytes, both B and T, than on blood cells. Although tonsil cells bear less PrPc than circulating blood lymphocytes, they are able to express high quantities of PrPc on their surface when placed in culture. However, contrary to previous results, mitogen stimulation does not affect this expression on B- or T-cells. INTERPRETATION AND CONCLUSIONS: We suggest that the PrPc expression by lymphocytes may be modified by interactions occurring during intratissular migration or during cell-to-cell contacts. Whether PrPc plays a role in intracellular communication at this location, as it does in the nervous system, remains an open question.

Dermal endothelial cells and keratinocytes produce IL-7 in vivo after human Schistosoma mansoni percutaneous infection.

The parasite Schistosoma mansoni infects its definitive mammalian host through an obligatory cutaneous penetration. In this work, we studied early immune response following migration of larvae through human skin, the first immunocompetent organ encountered by the parasite. For this purpose we used an experimental model of severe combined immunodeficient mice engrafted with human skin and injected with autologous PBL. Six days after percutaneous infection, we observed an infiltration of lymphocytes within the human skin, predominantly composed of CD4+ T cells. Moreover, among the cytokines potentially present in the infected skin, immunohistochemistry analysis revealed an in vivo expression of IL-7 in the epidermal layers and strikingly at the level of vascular endothelium. Using an in vitro coculture system, we showed that the S. mansoni larvae directly trigger IL-7 production by human dermal microvascular endothelial cells but not by keratinocytes. Finally, measurements of IL-7 concentrations in plasma of 187 S. mansoni-infected individuals showed that the youngest, which are also the most infected, displayed the highest IL-7 levels. Together, these findings describe dermal endothelial cells as a novel source of IL-7, a cytokine particularly important in schistosomiasis.

Primary Th1 cell immunization against HIVgp160 in SCID-hu mice coengrafted with peripheral blood lymphocytes and skin.

SCID-hu mouse models are of interest in the pathologic investigation of HIV infection, but obtaining a T cell response in SCID-hu-PBL mice is still controversial. We have developed a SCID model by engrafting human skin and autologous PBLs from HIV-seronegative individuals. The study describes the ability of this human-mouse chimera to generate in vivo a primary T lymphocyte response against HIV Ag. The injection of human autologous PBLs was performed 4 to 5 wk after the skin engraftment. Two weeks after injection of PBLs, chimeric mice were immunized with recombinant canary pox virus expressing HIV-1 LAIgp160 (vCP-LAIgp160) and supplemented or not with rIL-2. Intradermal vCP-LAIgp160 injection induced an intradermal perivascular human lymphocytic infiltrate and an epidermic network of CD1a+, CD80+, and CD86+ cells. We derived CD4+ T cell lines (STLs) from the human skin graft of immunized mice, showing that STLs mediated an MHC class II-restricted cytolytic activity directed against HIV-LAIgp160 Ags. Cytokine gene expression in both human skin cells and in STLs showed a predominance of IL-2, IFN-gamma, and IL-12 transcripts. Finally, the T cell repertoire analysis using the immunoscope technique showed a very limited CDR3 length polymorphism in the skin infiltrating lymphocytes suggesting an Ag-specific repertoire. The ability to induce a primary Th1 cell response in vivo affords a useful preclinical model for testing vaccine strategies.

Allergen-induced migration of human cells in allergic severe combined immunodeficiency mice.

Recently, we have shown that severe combined immunodeficiency (SCID) mice, intraperitoneally reconstituted with peripheral blood mononuclear cells (PBMC) from Dermatophagoides pteronyssinus (Dpt)-sensitive patients, produced human IgE and developed a pulmonary inflammatory-type reaction after exposure to allergen aerosol. In order to understand the potential mechanisms involved in the human cell migration in SCID mice, we analysed their phenotypic profile in the lungs, spleen and thymus, 2 months after Dpt inhalation. The human cell recruitment in these organs was found to be allergen-dependent as CD45+ human cells were only detected in hu-SCID mice after Dpt exposure. The composition of the pulmonary human T-cell infiltrate, preferentially memory (CD45RO), activated (human leucocyte antigen (HLA)-DR) and CD4+ cells, was similar to that described in asthmatic patients. However, CD20+ B cells were predominately recruited in the spleen and thymus and may be IgE-producing cells in the spleen. In the lungs, the percentage of human leucocytes expressing the alpha-chain of the lymphocyte function-associated antigen-1 (LFA-1) (CD11a) was higher than those of CD49d+ or CD54+ cells, in contrast to the spleen and thymus, suggesting a potential role of LFA-1 in the human cell migration towards SCID mice lung. In conclusion, this model could be useful in the study of factors implicated in the cellular migration towards the lymphoid organs during an allergic reaction.

Dose-dependent regression of HeLa cell-derived tumours in SCID mice after parvovirus H-1 infection.

Parvoviruses of rodents are endowed with oncosuppressive properties. In particular, parvoviral infections protect host animals from spontaneous and chemical- or virus-induced tumour initiation in laboratory animals. The present study was undertaken to substantiate the capacity of parvovirus H-1 to inhibit therapeutically the growth of established tumours originating from human carcinoma cells implanted in recipient mice. To this end, quickly growing s.c. carcinomas were established by injection of human cervical carcinoma cells (HeLa) into immunodeficient (SCID) mice. Tumour-bearing mice subsequently were inoculated with H-1 at various multiplicities of infection. H-1 virus infection led to regression of tumours, the onset and efficiency of which were dose-dependent.

The SCID mouse mutant: definition and potential use as a model for immune and hematological disorders.

Mice homozygous for a SCID mutation (SCID mice) are severely deficient in T and B lymphocytes. The absence of effector T and B cells has encouraged investigators to attempt engraftment of SCID mice with human fetal tissues, mature lymphocytes, hematopoietic progenitors and tumors. SCID mice can be reconstituted with human lymphocytes and are of interest for studying normal and abnormal lymphocyte development and function. SCID mice are also providing an in vivo model of infectious diseases. In addition, SCID mice readily support normal and pathologic human hematopoiesis differentiation and is useful for testing innovative hematological disease therapy. SCID mice with a fully functional human immune or hematopoietic system therefore seem to be extremely valuable for biomedical research.

Expression of a Schistosoma mansoni 28-kilodalton glutathione S-transferase in the livers of transgenic mice and its effect on parasite infection.

Schistosomiasis is a debilitating tropical disease for which an effective vaccine is needed. A 28-kDa glutathione S-transferase from Schistosoma mansoni (Sm28GST) has been shown to induce protective immunity. Sm28GST possesses significant sequence identity to mammalian GST isoforms. In order to study self-reactivity in mice immunized with Sm28GST and the concomitant phenomena of immune tolerance and epitope suppression, as well as their consequences for the protective immunity induced by this vaccination, we developed transgenic (Tg) mice that express Sm28GST under the control of a part of the mouse transferrin gene promoter. A study of (P28)Tg mice showed that the expression of Sm28GST was strictly localized in pericentrolobular hepatocytes. No histological change, inflammatory infiltrates, or modification of seric L-aspartate: 2-oxoglutarate aminotransferase concentration was observed over an 18-month period, despite a cross-reactivity between Sm28GST and a mouse molecule of 30 kDa. The immunoglobulin G anti-Sm28GST response of (P28)Tg mice immunized with recombinant Sm28GST was lower (P < 0.001) than that observed in non-(P28)Tg littermates and inversely proportional of Sm28GST liver expression. The response of non-(P28)Tg mouse spleen cells to Sm28GST stimulation was greater (P < 0.01) than that observed with (P28)Tg mouse spleen cells. (P28)Tg mice infected with 40 S. mansoni furcocercariae harbored more worms (P < 0.05) than did non-(P28)Tg control mice. The increase in the level of infection in (P28)Tg mice was reflected in concomitant increases in the numbers of adult worms and schistosome eggs found in livers and intestines after whole-body perfusion at 56 days postinfection, but no relative increase in the fertility of individual female worms was observed. The results obtained argue for the involvement of Sm28GST in reducing levels of infection and support the view that this enzyme has a central role in the maintenance of parasite viability, at least during its migration through host tissues.

Prevalence and clinical significance of antiphospholipid antibodies in heart valve disease: a case-control study.

The purposes of this study were (1) to assess the prevalence of antiphospholipid (aPL) antibodies in patients with non-specific heart valve disease referred for valve replacement and (2) to determine whether the presence of aPL antibodies carries a risk for thrombotic events during a postoperative follow-up in a prospective cohort. The sera of 89 consecutive patients and 80 matched control subjects were tested for antibodies to cardiolipin (immunoglobulin G and immunoglobulin M) and for lupus anticoagulant. The prevalence of aPL antibodies was significantly higher in patients (19 [21%] of 89) than in control subjects (7 [9%] of 80) (p < 0.05). Patients were divided into two subgroups according to the presence (subgroup A) or the absence (subgroup B) of aPL antibodies. No significant difference in age or sex ratio was observed between the two subgroups. A history of arterial thrombosis was more frequent in subgroup A (8 [42%] of 19) than in subgroup B (8 [11%] of 70) (p < 0.01). No significant difference with respect to the occurrence of thrombotic events was observed during a median follow-up period of 8.7 months. Thus a high prevalence of aPL antibodies was found in patients referred for heart valve replacement compared with matched control subjects. No increased risk has been demonstrated in the patients with aPL antibodies.

Thymocyte and thymic microenvironment alterations during a systemic HIV infection in a severe combined immunodeficient mouse model.

OBJECTIVE: A new model for systemic and multifocal HIV-1 infection was developed in severe combined immunodeficient (SCID) mice to study the alterations of thymocytes and of the thymic microenvironment that occur during a disseminated HIV infection. DESIGN AND METHODS: We grafted SCID mice with the classical human fetal thymus/liver co-implants together with fragments of autologous lungs (SCID-huLLT). These organs achieved normal differentiation and were productively infected after an intraperitoneal inoculation of two HIV-1 primary isolates. At time of sacrifice, thymic biopsies and thymic cell suspensions were analysed by immunohistochemistry, flow cytometry and lymphocyte function assays. RESULTS: At weeks 2-4 post-inoculation we observed the following thymocyte abnormalities: a minor to severe depletion of the immature CD1+CD4+CD8+ T cells (range, 0-73% thymocytes), compared with the persistence of mature CD4+ cells (11-50%) and amplification of CD8+ T cells (6-92%). The immature subset depletion was inversely related to the thymic HIV-1 viral load, suggesting the preferential infection of this subset. The residual mature thymocytes were functional as assessed by their sustained proliferative responses to CD3-triggering which contrasted with the lack of HIV-specific cytotoxic activity. A quantitative analysis of immunostained thymic sections revealed a disorganization and a densification of the thymic epithelial cells (TEC) network which occurred in all HIV-infected SCID-hu mice independently of the thymic CD1+CD4+CD8+ T-cell depletion. CONCLUSION: These results suggest that a systemic HIV infection induces in human thymuses from SCID-huLLT mice a preferential depletion of the immature thymocytes in the absence of mature CD4+ T-cell depletion, HIV-specific cytotoxic T-lymphocyte activity or thymic epithelial cell death, but is associated with dysplasia of the thymic microenvironment, and is therefore opening new perspectives for studying immune cell reconstitution strategies in HIV infection.