Thrombophilic factors do not predict outcomes in renal transplant recipients under prophylactic acetylsalicylic acid.

A cohort of recipients of renal transplant after 2000 (N=310) was prospectively screened on the day of transplantation and 1 month later for a panel of 11 thrombophilic factors to assess their effect on posttransplant outcomes. All patients received prophylactic acetylsalicylic acid, started before transplantation. The rate of thromboembolic events or acute rejection episodes during the first posttransplant year (primary composite endpoint) was 16.7% among patients free of thrombophilic factor (N=60) and 17.2% in those with >or=1 thrombophilic factor (N=250) (p>0.99). The incidence of the primary endpoint was similar among patients free of thrombophilic factors and those with >or=2 (N=135), or >or=3 (N=53) factors (16.3% and 15.1% respectively; p=1) and in patients who remained thrombophilic at 1 month (15.7%; p=0.84). None of the individual thrombophilic factor present at the day of transplantation was associated with the primary endpoint. The incidence of cardiovascular events at 1-year, serum creatinine at 1-year, 4-year actuarial graft and patient survival were not influenced by the presence of >or=1 thrombophilic factor at baseline (p=NS). In conclusion, the presence of thrombophilic factors does not influence thromboembolic events, acute rejection, graft or patient survival in patients transplanted after 2000 and receiving prophylactic acetylsalicylic acid.

[Sickle cell disease: exotic disease or a Belgian public health problem?]. / La drépanocytose: une affection exotique ou un problème de santé publique en Belgique?

Sickle cell disease is a genetic disorder involving the haemoglobin designated as haemoglobin S, an autosomic recessive hereditary disease. It is the most frequent hereditary disease in sub-Saharan Africa, however epidemiological studies performed with a systematic neonatal screening in Brussels and Liège have proven that more than one neonate over 2.000 has a sickle cell disease. If this amount is significant, at the level of each physician the number of patient-contacts will be weak. Another aspect of the disease is the variability in its expression: some patients suffer from multiple and chronic organ alterations while other suffer also from acute events which might lead to death if not treated appropriately. The poor experience of each physician, the lack of the disease knowledge by the population, the symptoms complexity, and the socio-economical aspects of sickle cell disease explain that it can be considered as an "exotic" disease but also as a public health problem. A global and dedicated approach of the patient as a whole must be implemented. This is the reason for the existence of the "Réseau des Hémoglobinopathies": http://www.redcellnet.be/.

[Medical genetics service]. / Le Service de Génétique Médicale.

Created in 1987, the department of medical genetics finds its origins in molecular endocrinology research which had developed from the seventies at the Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM) of the Faculty of Medicine. After its fusion with the Center of Human Genetics of the ULB, in 1992, the department is composed of three units: the lab of molecular genetics and oncology, the lab of cytogenetics and a clinical genetics unit. One thousand consultations of genetic counseling and more than 15,000 molecular or cytogenetic diagnostic procedures are performed annually. The development of the clinical activities was paralleled by a very active research activity, resulting in a series of "firsts". Amongst the main results are: the identification of the first mutations responsible for congenital hypothyroidism; the molecular cloning of the TSH receptor and of a series of "orphan" G protein-coupled receptors; the identification of a novel neuropeptide, nociceptin, by the first example of "reverse pharmacology"; the identification of olfactory receptors on the sperm of mammals, including man; the identification in molecular terms of the mechanisms responsible for acquired and hereditary hyperthyroidisms; the identification of the chemokine receptor CCR5 as the major coreceptor of HIV-1, and of the prevalent mutation of CCR5 conferring resistance to HIV to about 1% of the European population.

[Prevention of hemoglobinopathies in Brussels: a necessity?]. / Prévention des hémoglobinopathies à Bruxelles: une nécessité?

Haemoglobinopathies are the most frequent genetic diseases in the world. The estimated frequency of carriers in the world is of 200 millions while there is about 300.000 births per year of major forms of haemoglobinopathies. The neonatal screening of haemoglobinopathies performed at the Hospital Erasme on around 80% of births in Brussels since 1994 has demonstrated that the frequency of carriers of an abnormal haemoglobin is around 1.5% while more than 1/2.000 newborns has a major haemoglobinopathy. A strategy must be adopted to manage the haemoglobinopathies in Brussels.

Chorioretinal post-transplant lymphoproliferative disorder induced by the Epstein-Barr virus.

BACKGROUND: The Epstein-Barr virus (EBV) is responsible for the lymphoproliferative disorders observed in transplanted patients. METHODS: The case history is described of a 59 year old man with a chorioretinal lesion who had received a single lung transplant and was on immunosuppressive treatment. Immunoglobulin gene rearrangement and EBV detection by polymerase chain reaction (PCR) with semiquantification were used on the vitreous material. RESULTS: A proliferation of B lymphocytes with a monoclonal subpopulation was found by PCR on the vitreous sample. The large amounts of EBV genomes found in the vitreous suggest that EBV was the cause of the lymphoproliferation. Healing of the lesion was achieved by a decrease in immunosuppressive treatment and the use of nucleotide analogues. CONCLUSION: The diagnosis of ocular post-transplant lymphoproliferative disorder (PTLD) can be made by PCR on vitreous material. Early diagnosis and treatment can lead to regression of limited monoclonal lesions.

[Genetics of male sterility]. / Genetique de la sterilite masculine.

Infertility affects 10 to 15% of all couples, the man responsible being in approximately half of the cases. With the development of assisted reproductive technologies such as ICSI (Intracytoplasmic Sperm Injection), some infertile men can reproduce and transmit the infertility to their offspring. The genetic basis of male infertility has been extensively studied these last years. This article gives a non exhaustive overview of genetic defects associated with infertility, and emphasizes the importance of genetic screening, and possibly genetic counseling for these infertile males.

Subcutaneous panniculitis-like T-cell lymphoma: further evidence for a distinct neoplasm originating from large granular lymphocytes of T/NK phenotype.

We report the case of a 20 year-old caucasian woman who presented a primary subcutaneous panniculitis-like T-cell lymphoma (SPTCL) as an invasive tumor of the chest wall. Herein, the neoplastic cells were found to express a CD3+CD8+ phenotype but also displayed variably the natural killer (NK)-associated antigens CD56 and CD57 as well as granzyme B. On cytological examination, these cells showed a large granular lymphocyte (LGL)-like morphology with presence of azurophilic granules in their cytoplasm. Electron dense and membrane bound granules like those found in cytotoxic T lymphocytes (CTL) were also demonstrated by electron microscopy. Neither rearrangement of the T-cell receptor subunits nor Epstein-Barr virus (EBV) genome was observed at the molecular level. The LGL-like features of the neoplastic cells found in this case and the presence of NK-associated antigens provide additional support to the cytotoxic derivation of most SPTCL.

Relative contribution of Ki-ras gene analysis and brush cytology during ERCP for the diagnosis of biliary and pancreatic diseases.

BACKGROUND: Ki-ras mutation analysis from material collected during ERCP has been claimed to improve the diagnosis of pancreatic and bile duct carcinomas as compared with conventional cytology. Our aim was to study the relative contribution of both Ki-ras analysis and brush cytology in patients with a significant stricture at ERCP. METHODS: Brushings were collected in duplicate for both analyses in 142 patients in whom a definitive diagnosis was obtained by histology or a minimal follow-up of 6 months. RESULTS: For pancreatic strictures, sensitivity, specificity, and accuracy of Ki-ras analysis vs. cytology in detecting malignancy were 81% vs. 66%, 72% vs. 100%, and 70% vs. 74%, respectively. For biliary strictures, they were 25% vs. 42%, 100% vs. 100%, and 35% vs. 43%, respectively. The combination of the two methods only marginally increased their sensitivity and accuracy in both types of strictures. CONCLUSION: Ki-ras analysis is a sensitive method for diagnosing pancreatic but not biliary carcinoma. However, its specificity is lowered by a high frequency of Ki-ras mutations in patients with chronic pancreatitis (25%) who did not manifest cancer development within a 6-month follow-up period. In pancreatic duct strictures, brush cytology appears to be more specific in detecting malignancy; specificity for Ki-ras and cytology are equivalent for the diagnosis of malignant bile duct strictures. Therefore, making a clinical decision on the sole basis of Ki-ras analysis is probably not justified in the majority of the cases.

Evidence for the segregation of three different mutated alleles of the thyroglobulin gene in a Brazilian family with congenital goiter and hypothyroidism.

We have previously reported a Brazilian family with congenital goiter, hypothyroidism, and marked impairment of thyroglobulin (Tg) synthesis. Analysis of the Tg mRNA in the goiter of one of the siblings revealed a cytosine to thymine transition creating a stop codon at position 1510. This point mutation is removed from the majority of Tg mRNA transcripts by the preferential generation in the goiter of a 171 nt deleted Tg mRNA by alternative splicing. The nonsense mutation destroys a TaqI site at this position in the mutant Tg gene. Using polymerase chain reaction (PCR) amplification and TaqI digestion we found that two siblings affected with goiter and hypothyroidism, as well as the father and three siblings with normal thyroid function, are all heterozygous for the nonsense mutation. This implies that an additional mutation must be present in the affected individuals, generating a compound heterozygote genotype. A new polymorphism within the thyroglobulin gene represented by three alleles has been detected. This was documented by the TaqI restriction enzyme and phTgM3 probe hybridization that showed a three allelic polymorphism with fragment sizes of 16.5 kb (allele A), 14.5 kb (allele B) and 11.0 kb (allele C). Segregation analysis of these alleles in the family indicated that the two affected siblings were homozygous for the allele C. In contrast the unaffected father and three other siblings, who carried the nonsense mutation, were heterozygous for alleles B and C. Analysis of the Tg genotypes implies that two additional mutations of the Tg gene must segregate in this family to account for the observed phenotypes.

The deltaccr5 mutation conferring protection against HIV-1 in Caucasian populations has a single and recent origin in Northeastern Europe.

The chemokine receptor CCR5 is encoded by the CMKBR5 gene located on the p21.3 region of human chromosome 3, and constitutes the major co-receptor for the macrophage-tropic strains of HIV-1. A mutant allele of the CCR5 gene, Delta ccr5 , was shown to provide to homozygotes with a strong resistance against infection by HIV. The frequency of the Delta ccr5 allele was investigated in 18 European populations. A North to South gradient was found, with the highest allele frequencies in Finnish and Mordvinian populations (16%), and the lowest in Sardinia (4%). Highly polymorphic microsatellites (IRI3.1, D3S4579 and IRI3.2, D3S4580 ) located respectively 11 kb upstream and 68 kb downstream of the CCR5 gene deletion were used to determine the haplotype of the chromosomes carrying the Delta ccr5 variant. A strong linkage disequilibrium was found between Delta ccr5 and specific alleles of the IRI3.1 and IRI3.2 microsatellites: >95% of the Delta ccr5 chromosomes carried the IRI3.1-0 allele, while 88% carried the IRI3.2-0 allele. These alleles were found respectively in only 2 or 1.5% of the chromosomes carrying a wild-type CCR5 gene. From these data, it was inferred that most, if not all Delta ccr5 alleles originate from a single mutation event, and that this mutation event probably took place a few thousand years ago in Northeastern Europe. The high frequency of the Delta ccr5 allele in Caucasian populations cannot be explained easily by random genetic drift, suggesting that a selection advantage is or has been associated with homo- or heterozygous carriers of the Delta ccr5 allele.

Induction of specific T-cell responses in HIV infection.

OBJECTIVES: To induce recovery of HIV-1-specific immune responses by combining immunization with antiviral chemotherapy. DESIGN: Forty HIV-infected patients entered a double-blind study with recombinant gp160 in combination with zidovudine or placebo. The pretreatment observation period was around 2 years and the treatment period 5 years. Eighty matched HIV-infected patients served as controls. METHODS: Immune status was monitored by proliferation assays with HIV-specific antigens, mitogens and recall antigens. Viral load, CD4 cell counts, apoptosis, T-cell clonal analysis and CC-chemokine receptor (CCR)-5 status were determined. RESULTS: All immunized patients showed a strong and HIV-specific T-cell proliferative response. This response was related to the immunizations, and was not enhanced by the zidovudine monochemotherapy given during the first 6 months of the immunizations. The treatments did not significantly alter viral load. Potent antiviral combination therapy given to non-immunized individuals reduced their viral load but did not influence HIV-specific immune responses. There was a trend for an increased frequency of non-progression in the immunized group compared with controls. These individuals had both wild-type and mutant CCR-5 genes. CONCLUSION: The results clearly show that restoration of HIV-specific T-cell immunity occurs after immunization with the HIV gp160 antigen and is not influenced by the addition of antiviral monochemotherapy. Even intensive chemotherapy alone did not restore HIV-specific immunity and immunization alone did not influence viral load. This suggests that combinations of intensive chemotherapy with specific HIV immunization would result both in viral load reduction and improved immune responses to HIV.

ETV6 is the target of chromosome 12p deletions in t(12;21) childhood acute lymphocytic leukemia.

The presence of ETV6 deletions was investigated in 215 children with acute lymphoblastic leukemia (ALL) using the loss of heterozygosity (LOH) approach. We used four intragenic or juxtagenic microsatellite markers to detect allelic deletions. In this series of unselected patients, LOH of ETV6 markers was found in 23% of cases (6% of T-ALL and 26% of B lineage ALL) confirming that chromosome 12p12-13 deletions represent a major genetic alteration in childhood ALL, frequently missed by cytogenetic analysis. The presence of a t(12;21)(p13;q22) was studied by RT-PCR and/or FISH in a total of 134 patients (125 B lineage ALL, nine T-ALL) including 42 cases with LOH. Thirty-four out of 44 patients (77%) for whom a t(12;21) was observed displayed LOH of the ETV6 markers. When associated with a t(12;21), ETV6 is very likely to be the target of deletions as indicated by the detection of intragenic deletions in three patients. Although deletion of ETV6 and t(12;21) were associated in most patients, in eight cases (six B lineage and two T-ALL) LOH was detected at the ETV6 locus without ETV6-AML1 hybrid RNA. FISH studies conducted in five of these eight patients confirmed the absence of translocation involving ETV6. In such patients, the other allele of ETV6 could be disrupted by either a small deletion, a point mutation, or an epigenetic modification and it will be of interest to study the structure and expression of the remaining allele of ETV6 in these cases. Alternatively, a tumor suppressor gene located close to ETV6 and CDKN1B could be the target of deletions.

Morphologic and phenotypic changes of the leukemic cells in a case of marginal zone B-cell lymphoma.

A particular case of marginal zone B-cell lymphoma (MZBCL) presenting with leukemic lymphocytes is reported. In the present observation, the leukemic cells not only displayed a remarkable morphological fluctuation but also had an unusual phenotype, changing with time. These phenotypic features, which have been functionaly investigated by in vitro assays, might simply reflect an activation state depending on the microenvironment. Because of its disconcerting similarities with hairy cell leukemia (HCL) and splenic lymphoma with villous lymphocytes (SLVL), this case relaunches the debate about whether close relationships might exist between the splenic marginal zone, SLVL and HCL.

Nature of the T lymphocytes in lymphocyte predominance Hodgkin's disease.

Little is known about the function of the T lymphocytes in lymphocyte predominance Hodgkin's disease. We report here the case of a 37-year-old man with a diffuse LPHD, featuring a similar increase in T lymphocytes in both the peripheral blood and the tumor, thus allowing for their characterization by functional assays. These cells were CD4+CD45RO+ and produced high amounts of IL-2 and IFN-gamma, consistent with a TH1-type profile. This subset of T helper cells is involved in cellular immunity and could reflect a cytotoxic reaction directed against the neoplastic cells.

Disseminated angiosarcoma presenting as a hemophagocytic syndrome in a renal allograft recipient.

A case of angiosarcoma arising in the setting of transplantation is reported. This rare and malignant tumor of the endothelial system is seldom observed in allograft recipients, with only seven cases having been previously reported. What is interesting about the present observation is that the tumor is thought to have developed in the vicinity of a Dacron graft and that it showed prominent erythrophagocyte-like activity. This activity was associated with a particular clinical syndrome that shared some attributes with infection-associated hemophagocytic syndrome.

Slight instability of a FMR-1 allele over three generations in a family from the general population.

We report on a family segregating a FMR-1 allele within the "grey zone" of triplet repeat length (n = 51). The allele showed a 1-unit increment when transmitted through a female meiosis and a 1-unit increment when transmitted through a male of the next generation. At the following generation, a pregnant woman had amniocentesis performed. The latter showed she transmitted the allele unchanged (n = 53) to her male fetus. This family was not ascertained through an affected subject, and there was no family history of mental retardation. Thus our observation reflects the natural history of an unstable allele in the general population. Systematic analysis of such alleles may help refine our understanding of the grey zone of triplet repeat length.

Neurological disorders in members of families with Leber's hereditary optic neuropathy (LHON) caused by different mitochondrial mutations.

Neurological abnormalities have been occasionally associated with Leber's hereditary optic neuropathy (LHON). We describe four patients with spastic dystonia from two of our 35 LHON families. Magnetic resonance imaging revealed signal alterations of globus pallidus, putamen, internal capsula, and substantia nigra. Neuropathological findings in one of the patients with dystonia are described. Each of the dystonia families carries a different mtDNA mutation; one at np 3460 and one at np 11778. Periventricular multiple sclerosis-like white matter lesions were observed in one individual from a third family with the mtDNA 3460 mutation. Neurological disorders are probably underestimated in association with LHON.