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J L Casanova

Publications and source records attributed to J L Casanova.

At least 19 recordsLinked to original sources
PubMed2005

[Genetics and immunity of tuberculosis].

Tuberculosis, caused by Mycobacterium tuberculosis, is the most common mycobacterial disease in the world and remains a leading public health problem. Numerous other mycobacterial species are present in the environment and are most often termed atypical or nontuberculous mycobacteria. Like the attenuated vaccine Bacille Calmette-Guérin (BCG) they are generally poorly virulent, even so they can be at the origin of severe infections if the host immune response is impaired. It has been clearly demonstrated that the intrinsic virulence of a mycobacterial species is not the only factor determining disease severity, which is illustrated by the observation that the majority of individuals infected with M. tuberculosis do not develop clinical disease. Numerous arguments suggest that disease severity depends largely on susceptibility/resistance determined by the host genetic make up. In the following review we will discuss the studies on the genes implicated in complex predisposition to tuberculosis and Mendelian predisposition to disease caused by less virulent mycobacteria, proposing a continuous spectrum between those two types of predisposition.

Child↗
PubMed2005

Hematopoietic stem cell transplantation for Shwachman-Diamond syndrome: experience of the French neutropenia registry.

Our objective was to study the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) for Shwachman-Diamond Syndrome (SDS). Among 71 SDS patients included in the French Severe Chronic Neutropenia Registry, 10 received HSCT between 1987 and 2004 in five institutions. The indications were bone marrow failure in five cases, and myelodysplastic syndrome (MDS) or leukemia in five cases. The median follow-up of patients who survived without relapse is 6.9 years (3.1-16.8 years). The conditioning regimen consisted of a busulfan-cyclophosphamide combination (n=6) or total body irradiation plus chemotherapy (n=4). Six patients received stem cells from unrelated donors and four from identical siblings. Engraftment was complete in eight patients and unassessable in two patients. These latter two patients died of infections 32 and 36 days after HSCT, with grade IV graft-versus-host disease and multiorgan dysfunction. A third patient died from an acute respiratory distress syndrome 17 months after HSCT with progressive granulocytic sarcoma. One patient had an MDS relapse 4 months after HSCT and died 10 months later. The overall 5-year event-free survival rate is 60+/-15%. We conclude that HSCT is feasible for patients with SDS who develop bone marrow failure or malignant transformation.

Adolescent↗
PubMed2005

Risk groups in patients with bladder cancer treated with radical cystectomy: statistical and clinical model improving homogeneity.

PURPOSE: In this study we identified homogeneous risk groups, with no survival overlap among the subgroups that make up each risk group, in patients with transitional cell carcinoma of the bladder treated with radical cystectomy alone. MATERIALS AND METHODS: Predictive factors for tumor death were analyzed with univariate and multivariate analysis among a group of 298 patients with transitional cell carcinoma of the bladder treated with radical cystectomy alone. Independent variables were progressively incorporated according to their statistical power in a stepwise process identifying a model with independent subgroups. The risk groups were identified according to different survival cutoff points including subgroups with similar survival. To search a clinical application and to check the strength of this model a new model was also set up using the weight score based on the size of hazard ratio from multivariate analysis. RESULTS: Univariate analysis demonstrated that lymphatic invasion status, pathological stage (P), lymph node status (N) and prostatic stroma status (St) were predictive variables for tumor death, and the latter 3 were independent variables in the multivariate analysis. By taking the most powerful, N, as the reference variable, and progressively incorporating additional variables, a model was found including 7 independent subgroups. In this model only 2 subgroups, N1 and N2-3, included more than 1 category and their survival was also calculated. Three risk groups were identified establishing different survival cutoffs. The 5-year cancer specific survival rate was 86.4% for low risk (P1-2N0St-), 64.4% (range 60.9% to 65.3%) for intermediate risk (P1-2N1St-, P3N0St-, HR = 2.7) and 28.1% (range 0% to 47.7%) for high risk (N2-3, P4, St+, N1P3, HR = 8.7). This model was also reproduced using the weight score based on the size of the hazard ratio from the multivariate analysis CONCLUSIONS: Three homogeneous risk groups were identified with high statistically significant survival differences among them and no survival overlap among subgroups that make up the risk groups.

Adult↗
PubMed2005

Gamma interferon is dispensable for neopterin production in vivo.

Previous studies have indicated that neopterin is synthesized in vitro by human monocyte-derived macrophages and dendritic cells upon stimulation with gamma interferon (IFN-gamma). Neopterin production under specific conditions in vitro has also been obtained upon stimulation with IFN-alpha and/or IFN-beta. However, it is unknown if any IFN-gamma-independent neopterin synthesis is possible in vivo. In the present study we investigated the serum neopterin concentrations in patients affected by the syndrome of Mendelian susceptibility to mycobacterial disease (MSMD). Indeed, this syndrome is characterized by deeply impaired or absent IFN-gamma production or function due to severe mutations in molecules involved in IFN-gamma/interleukin-12 (IL-12)/IL-23-dependent pathway. Serum neopterin levels were measured by an enzyme-linked immunosorbent assay in 27 patients with MSMD. We found that serum neopterin levels are elevated in the complete absence of IFN-gamma activity due either to a complete deficiency of its receptor or to deleterious mutations of IL-12 or its receptor. These data clearly indicate that, as reported from in vitro studies, other stimuli are able to induce neopterin synthesis in vivo. Consequently, neopterin cannot be used as means of diagnosis of MSMD due to IFN-gamma-, IL-12-, and IL-23-dependent pathway defects.

Adolescent↗
PubMed2005

[Genetic predisposition and susceptibility to mycobacterial infections: the IL-12-IFNgamma axis deficiency].

Since ten years severe pediatric infections which were idiopathic have now molecular explanation, defined new primary immunodeficiencies. These children presented a new kind of hereditary immunodeficiency with severe and/or recurrent infections caused by only one micro-organisms family. Some of these children have mycobacterial infections. Standard immunologic explorations were normal. However, they presented a vulnerability, sometimes lethal caused by Mycobacteria. The goal of this article is to describe the IL-12-IFNgamma axis deficiency (mendelian susceptibility to mycobacterial disease).

Genetic Predisposition to Disease↗
PubMed2003

[New hereditary immunodeficiencies and genetic predisposition to infective diseases in children].

Since 10 years severe pediatric infections which were idiopathic have now molecular explanation, because new primary immunodeficiencies responsible of these severe infections were identified. These children presented a new kind of hereditary immunodeficiency with severe and/or recurrent infections caused by only one microorganisms family, in opposition to other patients with "classic" primary immunodeficiency. Standard immunologic explorations for example white blood counts, lymphocyte counts, vaccine serology, immunoglobulin levels and complement were normal. However, these children presented a vulnerability, sometimes lethal, caused by one type of microorganism. The aim of this review is to describe 3 new syndromes with a genetic predisposition of infectious diseases: IL-12-IFN gamma axis deficiency (Mendelian susceptibility to mycobacterial disease), STAT1 deficiency (predisposition to viral disease) and NEMO and IRAK-4 deficiencies (predisposition to infections caused by pyogenic bacteria).

Child↗
PubMed2003

Hematopoietic stem cell transplantation in patients with severe Langerhans cell histiocytosis and hematological dysfunction: experience of the French Langerhans Cell Study Group.

The aim of this study was to assess the results of hematopoietic stem cell transplantation (HSCT) in refractory Langerhans cell histiocytosis (LCH). Among 85 patients with LCH and hematological dysfunction diagnosed in France between 1987 and 2000, eight received HSCT in six institutions. Median age at diagnosis was 0.54 years. The median LCH activity score at diagnosis was 10 (range 3-20). All patients responded poorly to initial chemotherapy. At the time of HSCT, the median activity score was 16.5 (range 7-18). HSCT was autologous in three cases and allogeneic in five cases. The conditioning regimen consisted of TBI in two cases and chemotherapy alone in six cases. Conditioning had to be attenuated in two patients. All patients had persistent active disease after autologous HSCT, which was fatal in two cases and controlled by chemotherapy in one case. After allogeneic HSCT, two patients died from toxicity and three had complete responses; two patients had had no recurrences after 21 months and 7 years of follow-up, while the other patient relapsed and died from sepsis related to splenectomy. HSCT for refractory LCH can thus be highly toxic but can also achieve sustained disease control.

Chimera↗
PubMed2002

Reticular dysgenesis: HLA non-identical bone marrow transplants in a series of 10 patients.

Reticular dysgenesis is a very rare congenital immunodeficiency classified within the severe combined immunodeficiencies (SCID) and characterized by impairment of both lymphoid and myeloid cell development. We report our experience in 10 patients with RD, treated between 1979 and 1999 with HLA-haploidentical hematopoietic stem cell transplantation (HSCT). All children but one were symptomatic within the first days of their lives. Five patients required two HSCT. Five patients received conditioning therapy with busulfan (16 mg/kg) and cyclophosphamide. Three of them are alive and well with myeloid and T and B cell lymphoid reconstitution, whereas two patients died (one chronic graft-versus-host disease, one pneumonitis). Transplantation without or with other conditioning regimens in the other five cases led to absent or incomplete engraftment and none of these cases survived. These results demonstrate the mandatory need for intensive conditioning before haploidentical HSCT in RD to achieve full lymphoid and myeloid engraftment.

Bone Marrow Transplantation↗
PubMed2002

[Human mycobacterial infections: impact of host genetic factors].

Humans are exposed worldwide to a variety of environmental mycobacteria (EM) and most children are inoculated with live Bacille Calmette-Guérin (BCG) vaccine. Although rarely pathogenic, poorly virulent mycobacteria, including BCG and most EM, may cause a variety of clinical diseases. M. tuberculosis and M. leprae are more virulent, causing tuberculosis, and leprosy, respectively. Remarkably, only a minority of individuals develop clinical disease, even if infected with virulent mycobacteria. There is now accumulating evidence that the large interindividual variability of clinical outcome results in part from variability in the human genes that control host defense. We review here in current knowledge about genetic predisposition to common (leprosy and tuberculosis) and rare (BCG and EM infections) mycobacterial infections.

Genetic Predisposition to Disease↗
PubMed2001

The tight interallelic positional coincidence that distinguishes T-cell receptor Jalpha usage does not result from homologous chromosomal pairing during ValphaJalpha rearrangement.

The T-cell receptor (TCR) alpha locus is thought to undergo multiple cycles of secondary rearrangements that maximize the generation of alphabeta T cells. Taking advantage of the nucleotide sequence of the human Valpha and Jalpha segments, we undertook a locus-wide analysis of TCRalpha gene rearrangements in human alphabeta T-cell clones. In most clones, ValphaJalpha rearrangements occurred on both homologous chromosomes and, remarkably, resulted in the use of two neighboring Jalpha segments. No such interallelic coincidence was found for the position of the two rearranged Valpha segments, and there was only a loose correlation between the 5' or 3' chromosomal position of the Valpha and Jalpha segments used in a given rearrangement. These observations question the occurrence of extensive rounds of secondary Valpha-->Jalpha rearrangements and of a coordinated and polarized usage of the Valpha and Jalpha libraries. Fluorescence in situ hybridization analysis of developing T cells in which TCRalpha rearrangements are taking place showed that the interallelic positional coincidence in Jalpha usage cannot be explained by the stable juxtaposition of homologous Jalpha clusters.

3' Untranslated Regions↗
PubMed2001

Mendelian susceptibility to mycobacterial infection in man.

Selective susceptibility to weakly pathogenic mycobacteria, such as bacillus Calmette-Guérin (BCG) vaccine and environmental non-tuberculous mycobacteria (NTM), has long been suspected to be a Mendelian disorder but its molecular basis remained elusive. Recently, mutations in the interferon-gamma receptor ligand-binding chain (IFN gamma R1), interferon-gamma receptor signaling chain (IFN gamma R2), Signal Transducer and Activator of Transcription-1 (STAT-1), interleukin-12 p40 subunit (IL-12 p40), and interleukin-12 receptor beta 1 chain (IL-12R beta 1) genes have been identified in a number of patients with severe BCG or NTM infection. Dominant or recessive alleles causing complete or partial cellular defects have been found to define nine different inheritable disorders. Although genetically distinct, these conditions are immunologically related and highlight the essential role of interferon gamma-mediated immunity in the control of mycobacteria in man. The genetic and immunologic heterogeneity of this syndrome makes accurate diagnosis challenging but vital as decisions about the most appropriate treatment are best taken based on an accurate molecular diagnosis.

Adolescent↗
PubMed2001

Impairment of mycobacterial but not viral immunity by a germline human STAT1 mutation.

Interferons (IFN) alpha/beta and gamma induce the formation of two transcriptional activators: gamma-activating factor (GAF) and interferon-stimulated gamma factor 3 (ISGF3). We report a natural heterozygous germline STAT1 mutation associated with susceptibility to mycobacterial but not viral disease. This mutation causes a loss of GAF and ISGF3 activation but is dominant for one cellular phenotype and recessive for the other. It impairs the nuclear accumulation of GAF but not of ISGF3 in heterozygous cells stimulated by IFNs. Thus, the antimycobacterial, but not the antiviral, effects of human IFNs are principally mediated by GAF.

Adult↗
PubMed2001

Interleukin-12 receptor beta1 deficiency in a patient with abdominal tuberculosis.

Two siblings with interleukin-12 receptor beta1 (IL-12Rbeta1) deficiency but different clinical phenotypes were studied. Both are homozygous for an IL12RB1 missense mutation that prevents receptor expression and abolishes cellular responses to IL-12. Transfection of the patients' T cells with wild-type IL12RB1 restored IL-12Rbeta1 expression and function. One patient had the expected phenotype of disseminated bacille Calmette-Guérin (BCG) infection in early childhood, whereas the other did not develop BCG infection, despite 3 inoculations with live BCG. Abdominal tuberculosis was diagnosed in this second patient at age 18 years. To date, neither of them has had clinical disease caused by environmental mycobacteria. These observations show unexpected interfamilial and intrafamilial heterogeneity of the clinical phenotype associated with IL-12Rbeta1 deficiency. The patients may be resistant to BCG but remain vulnerable to Mycobacterium tuberculosis. A diagnosis of IL-12Rbeta1 deficiency should therefore be considered in selected patients with severe tuberculosis, despite their resistance to BCG and a lack of atypical mycobacteriosis.

Abdomen↗
PubMed2001

Primary immunodeficiency mutation databases.

Primary immunodeficiencies are intrinsic defects of immune systems. Mutations in a large number of cellular functions can lead to impaired immune responses. More than 80 primary immunodeficiencies are known to date. During the last years genes for several of these disorders have been identified. Here, mutation information for 23 genes affected in 14 immunodefects is presented. The proteins produced are employed in widely diverse functions, such as signal transduction, cell surface receptors, nucleotide metabolism, gene diversification, transcription factors, and phagocytosis. Altogether, the genetic defect of 2,140 families has been determined. Diseases with X-chromosomal origin constitute about 70% of all the cases, presumably due to full penetrance and because the single affected allele causes the phenotype. All types of mutations have been identified; missense mutations are the most common mutation type, and truncation is the most common effect on the protein level. Mutational hotspots in many disorders appear in CPG dinucleotides. The mutation data for the majority of diseases are distributed on the Internet with a special database management system, MUTbase. Despite large numbers of mutations, it has not been possible to make genotype-phenotype correlations for many of the diseases.

Alleles↗
PubMed2001

[Meningococcal purpura fulminans: untoward result of genetic polymorphism?].

Despite significant progress in intensive care medicine, the mortality of septic shock has not changed in recent years. Early recognition of subtle signs in favor of meningococcal sepsis, early antibiotic treatment, and aggressive hemodynamic support remains the cornerstone of therapy of severe meningococcal shock in children. Recent work has emphasized the role of genetic polymorphisms in various systems to explain the most severe cases: anti-inflammatory cytokine profile IL-10/TNF-alpha, elevated levels of plasminogen activator inhibitor type-1, variants of the gene for mannose-binding lectin complement pathway. This may explain the disillusionment of pediatric intensivists, and the general failure of immunotherapy for sepsis. Reasonable hope lies upon new meningococcal vaccines.

Child↗