An immunogenomic exome landscape of triple positive primary antiphospholipid patients

Primary antiphospholipid syndrome is characterized by thrombosis and autoantibodies directed against phospholipids or associated proteins. The genetic etiology of PAPS remains unknown. We enrolled 21 patients with thromboembolic events associated to lupus anticoagulant, anticardiolipin and anti β2 glycoprotein1 autoantibodies. We performed whole exome sequencing and a systematic variant-based analysis in genes associated with thrombosis, in candidate genes previously associated with APS or inborn errors of immunity. Data were compared to public databases and to a control cohort of 873 non-autoimmune patients. Variants were identified following a state-of-the-art pipeline. Enrichment analysis was performed by comparing with the control cohort. We found an absence of significant HLA bias and genetic heterogeneity in these patients, including when testing combinations of rare variants in genes encoding for proteins involved in thrombosis and of variants in genes linked with inborn errors of immunity. These results provide evidence of genetic heterogeneity in PAPS, even in a homogenous series of triple positive patients. At the individual scale, a combination of variants may participate to the breakdown of B cell tolerance and to the vessel damage.

Successful Allogenic Stem Cell Transplantation in Patients with Inherited CARD9 Deficiency

Autosomal recessive (AR) CARD9 (caspase recruitment domain-containing protein 9) deficiency underlies invasive infections by fungi of the ascomycete phylum in previously healthy individuals at almost any age. Although CARD9 is expressed mostly by myeloid cells, the cellular basis of fungal infections in patients with inherited CARD9 deficiency is unclear. Therapy for fungal infections is challenging, with at least 20% premature mortality. We report two unrelated patients from Brazil and Morocco with AR CARD9 deficiency, both successfully treated with hematopoietic stem cell transplantation (HSCT). From childhood onward, the patients had invasive dermatophytic disease, which persisted or recurred despite multiple courses of antifungal treatment. Sanger sequencing identified homozygous missense CARD9 variants at the same residue, c.302G>T (p.R101L) in the Brazilian patient and c.301C>T (p.R101C) in the Moroccan patient. At the ages of 25 and 44 years, respectively, they received a HSCT. The first patient received a HLA-matched HSCT from his CARD9-mutated heterozygous sister. There was 100% donor chimerism at D + 100. The other patient received a T cell-depleted haploidentical HSCT from his CARD9-mutated heterozygous brother. A second HSCT from the same donor was performed due to severe amegakaryocytic thrombocytopenia despite achieving full donor chimerism (100%). At last follow-up, more than 3 years after HSCT, both patients have achieved complete clinical remission and stopped antifungal therapy. HSCT might be a life-saving therapeutic option in patients with AR CARD9 deficiency. This observation strongly suggests that the pathogenesis of fungal infections in these patients is largely due to the disruption of leukocyte-mediated CARD9 immunity.

Utility of the QuantiFERON-TB Gold In-Tube assay for the diagnosis of tuberculosis in Moroccan children

SETTING

The utility of interferon-gamma release assays (IGRAs), such as the QuantiFERON-TB Gold In-Tube (QFT-GIT) test, in diagnosing active tuberculosis (TB) in children is unclear and depends on the epidemiological setting.

OBJECTIVE

To evaluate the performance of QFT-GIT for TB diagnosis in children living in Morocco, an intermediate TB incidence country with high bacille Calmette-Gurin vaccination coverage.

DESIGN

We prospectively recruited 109 Moroccan children hospitalised for clinically suspected TB, all of whom were tested using QFT-GIT.

RESULTS

For 81 of the 109 children, the final diagnosis was TB. The remaining 28 children did not have TB. QFT-GIT had a sensitivity of 66% (95%CI 5277) for the diagnosis of TB, and a specificity of 100% (95%CI 88100). The tuberculin skin test (TST) had lower sensitivity, at 46% (95%CI 3360), and its concordance with QFT-GIT was limited (69%). Combining QFT-GIT and TST results increased sensitivity to 83% (95%CI 6992).

CONCLUSION

In epidemiological settings such as those found in Morocco, QFT-GIT is more sensitive than the TST for active TB diagnosis in children. Combining the TST and QFT-GIT would be useful for the diagnosis of active TB in children, in combination with clinical, radiological and laboratory data.

Pott's disease in Moroccan children: clinical features and investigation of the interleukin-12/interferon-γ pathway

SETTING

Tuberculosis spondylodiscitis (TS), or Pott's disease, an extra-pulmonary form of tuberculosis (TB), is rare and difficult to diagnose in children. Some cases of severe TB in children were recently explained by inborn errors of immunity affecting the interleukin-12/interferon-gamma (IL-12/IFN-γ) axis.

OBJECTIVE

To analyse clinical data on Moroccan children with TS, and to perform immunological and genetic explorations of the IL-12/IFN-γ axis.

DESIGN

We studied nine children with TS diagnosed between 2012 and 2014. We investigated the IL-12/IFN-γ circuit by both whole-blood assays and sequencing of the coding regions of 14 core genes of this pathway.

RESULTS

A diagnosis of TS was based on a combination of clinical, biological, histological and radiological data. QuantiFERON(®)-TB Gold In-Tube results were positive in 75% of patients. Whole-blood assays showed normal IL-12 and IFN-γ production in all but one patient, who displayed impaired decreased response to IL-12. No candidate disease-causing mutations were detected in the exonic regions of the 14 genes.

CONCLUSIONS

TS diagnosis in children remains challenging, and is based largely on imaging. Further investigations of TS in children are required to determine the role of genetic defects in pathways that may or may not be related to the IL-12/IFN-γ axis.

Loss of B Cells in Patients with Heterozygous Mutations in IKAROS

BACKGROUND

Common variable immunodeficiency (CVID) is characterized by late-onset hypogammaglobulinemia in the absence of predisposing factors. The genetic cause is unknown in the majority of cases, and less than 10% of patients have a family history of the disease. Most patients have normal numbers of B cells but lack plasma cells.

METHODS

We used whole-exome sequencing and array-based comparative genomic hybridization to evaluate a subset of patients with CVID and low B-cell numbers. Mutant proteins were analyzed for DNA binding with the use of an electrophoretic mobility-shift assay (EMSA) and confocal microscopy. Flow cytometry was used to analyze peripheral-blood lymphocytes and bone marrow aspirates.

RESULTS

Six different heterozygous mutations in IKZF1, the gene encoding the transcription factor IKAROS, were identified in 29 persons from six families. In two families, the mutation was a de novo event in the proband. All the mutations, four amino acid substitutions, an intragenic deletion, and a 4.7-Mb multigene deletion involved the DNA-binding domain of IKAROS. The proteins bearing missense mutations failed to bind target DNA sequences on EMSA and confocal microscopy; however, they did not inhibit the binding of wild-type IKAROS. Studies in family members showed progressive loss of B cells and serum immunoglobulins. Bone marrow aspirates in two patients had markedly decreased early B-cell precursors, but plasma cells were present. Acute lymphoblastic leukemia developed in 2 of the 29 patients.

CONCLUSIONS

Heterozygous mutations in the transcription factor IKAROS caused an autosomal dominant form of CVID that is associated with a striking decrease in B-cell numbers. (Funded by the National Institutes of Health and others.).

A genome-wide association study of pulmonary tuberculosis in Morocco

Although epidemiological evidence suggests a human genetic basis of pulmonary tuberculosis (PTB) susceptibility, the identification of specific genes and alleles influencing PTB risk has proven to be difficult. Previous genome-wide association (GWA) studies have identified only three novel loci with modest effect sizes in sub-Saharan African and Russian populations. We performed a GWA study of 550,352 autosomal SNPs in a family-based discovery Moroccan sample (on the full population and on the subset with PTB diagnosis at <25 years), which identified 143 SNPs with p < 1 × 10(-4). The replication study in an independent case/control sample identified four SNPs displaying a p < 0.01 implicating the same risk allele. In the combined sample including 556 PTB subjects and 650 controls these four SNPs showed suggestive association (2 × 10(-6) < p < 4 × 10(-5)): rs358793 and rs17590261 were intergenic, while rs6786408 and rs916943 were located in introns of FOXP1 and AGMO, respectively. Both genes are involved in the function of macrophages, which are the site of latency and reactivation of Mycobacterium tuberculosis. The most significant finding (p = 2 × 10(-6)) was obtained for the AGMO SNP in an early (<25 years) age-at-onset subset, confirming the importance of considering age-at-onset to decipher the genetic basis of PTB. Although only suggestive, these findings highlight several avenues for future research in the human genetics of PTB.

[Purulent pericarditis and colonic infiltrating to Salmonella enteritidis complicated by acute intussusception in a case of IL-12Rβ1 deficiency]

IL-12 receptor β1 deficiency (IL-12Rβ1) predisposes patients to mycobacteria and Salmonella infections. We report a case of IL-12Rβ1 deficiency with a fatal multi-resistant Salmonella enteritidis infection. This boy was born after from a consanguineous marriage, and diagnosed as having a IL-12Rβ1 deficiency since the age of 3 months. He presented with recurrent Salmonella enteritidis essentially digestive localization, complicated by purulent pericarditis at the same germ at the age of two and a half years. At the age of 3, a colonic infiltration due to a Salmonella enteritidis resistant to antibiotics, was complicated by acute intussusception, and the child died. The IL-12Rβ1 deficiency is considered as having a good prognosis, in contrast to what happened in our patient. We review therapeutic issues in these patients.

Pineal germinoma in a child with interferon-γ receptor 1 deficiency. case report and literature review

Interferon-γ receptor 1 (IFN-γR1) deficiency is one of the primary immunodeficiencies conferring Mendelian Susceptibility to Mycobacterial Disease (MSMD). Some cases of neoplasms have been recently reported in patients with MSMD, underlying the already known link between immunodeficiency and carcinogenesis. We report the first case of intracranial tumour, i.e. pineal germinoma, in a 11-year-old patient with complete IFN-γR1 deficiency. The first clinical presentation of the genetic immunodeficiency dates back to when the child was aged 2 y and 10 mo, when he presented a multi-focal osteomyelitis caused by Mycobacterium scrofulaceum. The diagnosis of IFN-γR1 deficiency (523delT/523delT in IFNGR1 gene) was subsequently made. The child responded to antibiotic therapy and remained in stable clinical condition until the age of 11 years, when he started complaining of frontal, chronic headache. MRI revealed a solid pineal region mass lesion measuring 20 × 29 × 36 mm. Histological findings revealed a diagnosis of pineal germinoma. The patient received chemotherapy followed by local whole ventricular irradiation with boost on pineal site, experiencing complete remission, and to date he is tumor-free at four years follow-up. Four other cases of tumors have been reported in patients affected by MSMD in our knowledge: a case of Kaposi sarcoma, a case of B-cell lymphoma, a case of cutaneous squamous cell carcinoma and a case of oesophageal squamous cell carcinoma. In conclusion, in patients with MSMD, not only the surveillance of infectious diseases, but also that of tumors is important.

Congenital IL-12R1β receptor deficiency and thrombophilia in a girl homozygous for an IL12RB1 mutation and compound heterozygous for MTFHR mutations: A case report and literature review

Interleukin-12 (IL-12) plays an important role in the production of interferon gamma from T cells and natural killer cells and is essential for protection against intra-macrophagic pathogens such as Mycobacterium and Salmonella. Here, we describe a 16-year-old girl with homozygous mutation in exon 12 of the IL12RB1 gene, which causes complete IL-12Rβ1 deficiency in association with heterozygous mutation (C677T and A1298C) in the methylenetetrahydrofolate reductase gene. She presented with disseminated Mycobacterium tuberculosis complex infection, retroperitoneal fungal abscess and also thrombosis in the superior mesenteric-portal vein junction. This is the first case report of a primary immunodeficiency associated with a genetically determined venous thrombosis.

[Human genetics of tuberculosis]

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major public health problem worldwide, resulting in 8.7 million new cases and 1.4 million deaths each year. One third of the world's population is exposed to M. tuberculosis and, after exposure, most, but not all, individuals become infected. Among infected subjects, only a minority (∼10%) will eventually develop clinical disease, which is typically either a primary, often extra-pulmonary, TB in children, or a reactivation, pulmonary TB in adults. Considerable genetic epidemiological evidence has accumulated to support a major role for human genetic factors in the development of TB. Numerous association studies with various candidate genes have been conducted in pulmonary TB, with very few consistent results. Recent genome-wide association studies revealed only a modest role for two inter-genic polymorphisms. However, a first major locus for pulmonary TB was mapped to chromosome 8q12-q13 in a Moroccan population after a genome-wide linkage screen. Using a similar strategy, two other major loci controlling TB infection were recently identified. While the precise identification of these major genes is ongoing, the other fascinating observation of these last years was the demonstration that TB can also reflect a Mendelian predisposition. Following the findings obtained in the syndrome of Mendelian susceptibility to mycobacterial diseases, several children with complete IL-12Rβ1 deficiency, were found to have severe TB as their sole phenotype. Overall, these recent findings provide the proof of concept that the human genetics of TB involves a continuous spectrum from Mendelian to complex predisposition with intermediate major gene involvement. The understanding of the molecular genetic basis of TB will have fundamental immunological and medical implications, in particular for the development of new vaccines and treatments.

Bacille Calmette-Guérin lymphadenitis and recurrent oral candidiasis in an infant with a new mutation leading to interleukin-12 receptor beta-1 deficiency

Mendelian susceptibility to mycobacterial diseases (MSMD) is a rare syndrome characterized by predisposition to infections caused by weakly virulent mycobacteria, such as those in bacille Calmette-Guérin (BCG) vaccine and environmental mycobacteria. Salmonellosis has been reported in almost half of affected patients. Patients are also vulnerable to Mycobacterium tuberculosis infection. Several other infectious diseases may occur, albeit rarely. Mucocutaneous candidiasis is more common. Interleukin-12 receptor beta1 (IL-12Rbeta1) deficiency is the most frequent genetic cause of MSMD. Here, we describe an infant with a single episode of BCG lymphadenitis who also suffered from recurrent oral candidiasis. Genetic analysis revealed a new homozygous mutation (64+1G>T) in the IL12RB1 gene that caused complete IL-12R1beta1 deficiency. IL-12Rbeta1 deficiency should be considered in patients with BCG infection, even in those who experience a single episode of BCG lymphadenitis or recurrent mucocutaneous candidiasis. Every attempt should be made to heighten awareness in countries where BCG vaccination is performed.

Novel primary immunodeficiencies relevant to internal medicine: novel phenotypes

Primary immunodeficiencies (PIDs) are often recognized in adults, either because of delayed diagnosis of a paediatric illness, or increasingly because of the recognition of adult onset forms of these diseases. Moreover, a growing fraction of children diagnosed with PIDs reach adulthood. It has become clear that many of these conditions affect various organs and therefore will be referred to professionals from various fields of internal medicine. It is well known that infectious diseases, allergy, auto-immunity and cancer may result from PIDs. Surprisingly, other clinical manifestations were recently found to reflect inborn errors of immunity. Ground-breaking discoveries suggest that atypical haemolytic uraemic syndrome, Crohn's disease, and alveolar proteinosis may actually be manifestations of novel PIDs.

[Multifocal infection due to Mycobacterium intracellulare: first case of interferon gamma receptor partial dominant deficiency in tropical French territory]

Nontuberculous mycobacterial infections are rare in immunocompetent children, and usually present as adenitis. We report a case of a 6-year-old girl with a multifocal chronic osteomyelitis and pulmonary localisation due to Mycobacterium intracellulare associated with an autosomal dominant mutation of interferon gamma receptor 1 gene (INFGR1) leading to a syndrome of mendelian predisposition to mycobacteria infections by partial deficiency of intracellular signalisation of gamma interferon. This child has been cured with anti-mycobacteria drugs and gamma interferon. This report focus on the importance of looking for a susceptibility of the host to infectious diseases, which can lead to a specific treatment. As far as we know, this is the first case described in a tropical area.

Host genetics of mycobacterial diseases in mice and men: forward genetic studies of BCG-osis and tuberculosis

In humans, genetic factors have long been suspected to contribute to the onset and outcome of tuberculosis. Such effects are difficult to identify owing to their complex inheritance, and to the confounding impact of environmental factors, notably pathogen-associated virulence determinants. Recently, forward genetic approaches in mouse models and in human populations have been used to elucidate a molecular basis for predisposition to mycobacterial diseases. The genetic dissection of host predisposition to infection with Mycobacterium bovis BCG and M. tuberculosis will help to define the key molecules involved in host antituberculous immunity and should provide new insights into this important infectious disease.

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.

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.

Syndrome de susceptibilite mendélienne aux infections mycobacteriennes : défauts de l’axe Interleukine-12 - Interféron

INTRODUCTION

Environmental non tuberculous mycobacteria and Bacillus Calmette-Guerin vaccines are weakly virulent mycobacteria. Nevertheless they may cause severe diseases in otherwise healthy children with no overt immunodeficiency. Parental consanguinity and familial forms are frequently observed among these patients, therefore this syndrome was named "Mendelian Susceptibility to Mycobacterial Disease".

STATE OF THE ART

In the last nine years, fife genes have been found to be mutated in patients with this syndrome: IFNGR1, IFNGR2, STAT1, IL12B, IL12RB1. Allelic heterogeneity accounts for ten distinct genetic disorders. Clinical phenotype differs between patients. The spectrum of disease extends from early-onset overwhelming mycobacterial infection to adult-onset localized disease and tuberculosis. Impaired IFN-gamma-mediated immunity is the common mechanism of the disease, outlining its major role in mycobacterial immunity.

PERSPECTIVES AND CONCLUSIONS

Better understanding of these disorders reveals an expanding clinical phenotype which justifies studying adult patients with pulmonary non tuberculous mycobacterial infection without known risk factors, severe BCGitis and recurrent tuberculosis. Molecular diagnosis makes it possible to introduce a specific regimen based on physiopathology.

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.

Génétique et immunité de la tuberculose

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.

[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).

Impact of HLA matching on outcome of hematopoietic stem cell transplantation in children with inherited diseases: a single-center comparative analysis of genoidentical, haploidentical or unrelated donors

SUMMARY

Hematological inherited diseases can be cured by hematopoietic stem cell transplantation (HSCT) from an human leukocyte antigen (HLA)-identical sibling donor (MSD), but the outcome of unrelated donors (URD) or haploidentical donors (HMD) has been a cause of concern. In all, 94 children affected with inherited diseases underwent HSCT at a single center using MSD (group A, n=31), URD (group B, n=23) or HMD (group C, n=40). There was no difference in the rate of engraftment or in the incidence of grades III-IV acute graft-versus-host disease (GVHD) between the groups. Survival rate was 80.6% in group A, 62.5% in group B and 47.5% in group C (P=0.023). In group B, survival rate was 73.7% in the subgroup with zero or one class I mismatch, and 25% in the subgroup with two or more class I mismatches (P=0.04). In group C, survival rate was 83.3% in the 9/10-identical subgroup, 64.3% in the seven or 8/10 subgroup, and 25% in the five or 6/10 subgroup (P=0.0007). Thus, engraftment, incidence of GVHD and survival are similar in recipients of grafts from MSD, URD with 0-1 class I-mismatch, or HMD with at least 7/10 HLA matches. The low success of HSCT using more disparate donors suggests reserving them for patients with very poor prognosis.

[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).

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.

Inherited disorders of IL-12- and IFNgamma-mediated immunity: a molecular genetics update

In the last 6 years, considerable advances have been made in the molecular analysis of a rare clinical syndrome: Mendelian susceptibility to mycobacterial disease (MSMD). Infection with poorly virulent environmental non-tuberculous mycobacteria (NTM) or vaccination with bacillus Calmette-Guerin (BCG) may cause disseminating and even fatal disease in individuals suffering from this syndrome. Mutations in five genes (IFNGR1, IFNGR2, STAT1, IL12B and IL12RB1) have been shown to be responsible for MSMD and further allelic heterogeneity accounts for the existence of nine distinct inherited disorders. All of these disorders are caused by impaired IFNgamma-mediated immunity. These results have important medical and biological implications. In this report, we update the disease-causing mutations reported in the literature.

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.

Aspergillus antigen and PCR assays in bone marrow transplanted children

Screening for Aspergillus antigen and DNA has been introduced for the early diagnosis of invasive aspergillosis (IA) in adults, but data in children at risk are scarce. Seventeen 1-108 month-old children were screened for Aspergillus antigenaemia by a commercial assay before and after bone marrow transplantation (BMT). Seventy-one serum samples were examined retrospectively by a novel nested PCR assay. Results of both assays were correlated with clinical, radiological and microbiological findings used for the definition of invasive aspergillosis by the European Organisation for Research and Treatment of Cancer (EORTC). Three cases of probable or possible IA were defined, and in 14 children invasive aspergillosis was ruled out. In 10 children, Aspergillus antigen was detected in at least two consecutive serum samples, a microbiological EORTC criteria of IA. Specific DNA was detected in 8 antigen-positive and 2 antigen-negative sera. A positive predictive value of 20% was calculated for both assays. Hence, a high rate of positive results of antigen Elisa and PCR assays in BMT children are due to transient antigenaemia and fungaemia without clinical relevance. According to our data, prospective studies in well defined pediatric patients are urgently needed to determine the value of serial Aspergillus PCR assays for the early diagnosis of invasive aspergillosis in children at risk.

[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.

Heterogeneity in the granulomatous response to mycobacterial infection in patients with defined genetic mutations in the interleukin 12-dependent interferon-gamma production pathway

Patients with genetic lesions in the Type-1 cytokine/cytokine receptor pathway exhibit a selective susceptibility to severe infections with poorly pathogenic mycobacteria and non-typhi salmonella spp. These experiments of nature demonstrate that IL-12-dependent IFNgamma production is critical for granuloma formation and therefore host immunity against such pathogens. The essential role of granuloma formation for protective immunity to these organisms is emphasized by the differing granuloma forming capabilities and resultant clinical sequelae observed in these patients which seems to reflect their ability to produce or respond to IFNgamma (Fig. 9). At one pole of this spectrum, represented by the complete IFNgammaR1/2 deficient patients, there is a complete absence of mature granuloma formation, whereas with the less severe mutations (i.e. partial IFNgammaR1/2, complete IL-12p40 and complete IL-12Rbeta1 deficiency), granuloma formation is very heterogenous with wide variations in composition being observed. This suggests that in the latter individuals, who produce partial but suboptimal IFNgamma responses, other influences, including pathogen virulence and host genotype may also affect the type and scale of the cellular response elicited.

Mycobacterial diseases in primary immunodeficiencies

Primary immunodeficiency diseases comprise over 100 conditions, each associated with a variety of viral, bacterial, fungal and protozoan infections. M. tuberculosis and less virulent mycobacteria, such as bacille Calmette-Guérin vaccines and environmental non-tuberculous mycobacteria, may cause severe disease in patients with primary immunodeficiency diseases. However, no previous review has dealt with the issue of which primary immunodeficiency diseases predispose affected individuals to mycobacterial disease. This information is very useful, not only increasing our understanding of human immunity to mycobacteria, but also for the diagnostic investigation of patients with mycobacteriosis. We review here the medical literature on cases of mycobacterial disease in patients with primary immunodeficiency diseases.

[T-cell-depleted HLA non-identical bone marrow transplantation in the child: prevention of graft-versus-host reaction by administration of donor T lymphocytes alloreactive against the recipient]

The success of HSCT from HLA partially disparate donors depends on the development of new strategies able to efficiently prevent GVHD and to protect patients from infections and relapse. Using an immunotoxin (IT) directed against the alpha-chain (p55) of the human IL-2r (RFT5-SMPT-dgA), we have previously shown that it is possible to kill mature T cells activated towards a specific HLA complex by a one-way MLR. We designed a clinical trial assessing the effect of infusing increasing doses of T lymphocytes in the setting of children recipients of non HLA genetically identical HSCT. Thirteen patients have been enrolled from September 1998 to April 2000 and fourteen HSCT have been realized in 13 patients (pts). Donors were MUD in 3 cases and familial HLA partially disparate in the remaining cases. Allodepleted donor T cells were injected between day +14 and day +30 provided that ATG was undetectable in the serum and blood PMN counts was > 500/microliter. The mean age of these patients was 17 months (range 1 to 42). Diagnosis included immune deficient and malignant hemopathies. Three patients received 1 x 10(5) allodepleted T cell/kg, 7 patients received 4 x 10(5)/kg and 4 patients received 6 x 10(5)/kg allodepleted T cells. Full inhibition of MLR was achieved in 12 out of 14 cases. In two cases, a residual T cell reactivity to the recipient was observed (4 to 5%) and patients developed grade II aGVHD. aGVHD occurred in 4 out of 11 grafted patients (all grade II). No chronic GVHD has developed, so far. Three patients died from severe VOD or PHT at day +34, day 51 and day +166, while one infected patient by VZV, CMV and EBV before HSCT died 6 months after transplantation from meningoencephalitis and another patient died from relapse at day +291. The patient for which there was no engraftment died at day +48 from staphylococcus infection. Overall survival is 54%, with a median follow up of 8 months; the mean time to reach a blood lymphocyte count > 500 was 41 days, to reach a CD3 count > 300 microliters 63 days (20-111), CD4 > 200 microliters 97 days and positive mitogen-induced proliferation 90 days. In three patients, a tetanus-toxoid positive proliferation was detected before immunization. From this intermediate analysis, we conclude that 1) specific allodepletion is an effective approach to prevent aGVHD in a haploincompatible setting, 2) data on immunological reconstitution suggest that infused T cells do survive and expand. A higher number of patients must be enrolled to determine the optimal number of T cells to infuse.

Interferon-gamma receptor deficiency mimicking Langerhans' cell histiocytosis

Two patients who were initially given a diagnosis of Langerhans' cell histiocytosis on the basis of the clinical, radiologic, and biopsy findings had mycobacterial infection subsequently identified. The correct diagnosis of dominant partial interferon-gamma receptor deficiency was established.

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.

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.

[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.

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.

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.

Impaired interferon gamma-mediated immunity and susceptibility to mycobacterial infection in childhood

Mendelian susceptibility to poorly virulent mycobacteria such as bacillus Calmette-Guerin (BCG) and environmental nontuberculous mycobacteria is a clinically heterogeneous syndrome. The clinical features of affected children cover a continuous spectrum from disseminated lethal bacillus Calmette-Guerin infection to local recurrent nontuberculous mycobacterial infection. Different types of mutations in four genes (IFNGR1, IFNGR2, IL12B, IL12RB1) have revealed both allelic and nonallelic heterogeneity and result in eight different disorders whose common pathogenic pathway is impaired interferon gamma (IFNgamma) mediated immunity. The severity of the clinical phenotype depends on the genotype. Complete IL-12 p40 and IL-12 receptor beta1 deficiencies and partial IFNgamma receptor 1 (IFNgammaR1) and IFNgammaR2 deficiencies generally lead to curable infections at various ages, and antibiotics supplemented with IFNgamma if required are likely to be effective. Complete IFNgammaR1 and IFNgammaR2 deficiencies predispose to overwhelming infection in early childhood, which may respond to antibiotics but relapse when antibiotics are discontinued. Rapid discrimination between complete IFNgammaR1 and IFNgammaR2 deficiency and other defects, therefore, is an important diagnostic step for planning clinical management.

Prospective validation of the association of local tumor stage and grade as a predictive factor for occult lymph node micrometastasis in patients with penile carcinoma and clinically negative inguinal lymph nodes

PURPOSE

We prospectively validated the association of local tumor stage and grade as a predictive factor for occult lymph node micrometastasis in patients with penile carcinoma and clinically negative lymph nodes.

MATERIALS AND METHODS

In a retrospective study of 66 patients we demonstrated the predictive value of the association of local tumor stage and grade for occult micrometastasis, identifying 3 risk groups. A therapy strategy was designed according to these risk groups. A total of 37 consecutive patients were included in a prospective study in which the same criteria for risk group allocation and the same therapeutic recommendations were used as in the retrospective study.

RESULTS

In the prospective study we noted positive lymph nodes in 11% of stage T1, 63% of stages T2-3, 15% of grade 1, 67% of grade 2 and 75% of grade 3 cases. The incidence of positive nodes was 0% in the low, 83.3% in the high and 33.3% in the intermediate risk group. These rates were similar to those in the retrospective study with no significant difference.

CONCLUSIONS

The predictive value of the association of local tumor stage and grade for occult lymph node micrometastasis was validated in a prospective study. This factor allows the differentiation of 3 risk groups of patients with high reliability in the low and high risk groups. However, other prognostic factors are needed in the intermediate risk group to improve the prediction of lymph node involvement.