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V Fremeaux-Bacchi

Publications and source records attributed to V Fremeaux-Bacchi.

8 recordsLinked to original sources
PubMed2005

[Neisseria meningitidis infection. Clinical criteria orienting towards a deficiency in the proteins of the complement].

OBJECTIVE: Complement protein deficiency of the classical pathway or in proteins of the alternate pathway is rare but considerably increase the risk of infection with Neisseria meningitidis. The aim of this study was to determine the clinical criteria of the group at risk. METHODS: Retrospective study of the clinical and biological data of patients exhibiting complement protein deficiency associated with one or several N. meningitidis infections. RESULTS: Forty cases were studied, including 35 classical pathway protein deficiencies, with a predominance of C7 deficiency, 3 properdin deficiencies and 2 acquired C3 deficiencies. More than 60% of the patients exhibited recurrent N. meningitidis infections. Serogroups of rare strains were isolated in 50% of cases. Properdin deficiency was associated with a fulminating form in 2 cases out of 3. The age at onset of the first manifestations varied from 2 months to 32 years. CONCLUSION: A deficiency must be systematically searched for in all patients presenting with a N. meningitidis infection before the age of 6 months or after the age of 5 years. Identification of deficient patients permits the proposal of family screening and appropriate prophylaxis, including preventive vaccination.

Adolescent↗
PubMed2005

The development of atypical haemolytic-uraemic syndrome is influenced by susceptibility factors in factor H and membrane cofactor protein: evidence from two independent cohorts.

BACKGROUND: In both familial and sporadic atypical haemolytic-uraemic syndrome (aHUS), mutations have been reported in regulators of the alternative complement pathway including factor H (CFH), membrane cofactor protein (MCP), and the serine protease factor I (IF). A characteristic feature of both MCP and CFH associated HUS is reduced penetrance and variable inheritance; one possible explanation for this is that functional changes in complement proteins act as modifiers. OBJECTIVE: To examine single nucleotide polymorphisms in both CFH and MCP genes in two large cohorts of HUS patients (Newcastle and Paris). RESULTS: In both cohorts there was an association with HUS for both CFH and MCP alleles. CFH and MCP haplotypes were also significantly different in HUS patients compared with controls. CONCLUSIONS: This study suggests that there are naturally occurring susceptibility factors in CFH and MCP for the development of atypical HUS.

Alleles↗
PubMed2003

Restricted genetic defects underlie human complement C6 deficiency.

Complement C6 homozygous deficiency (C6D) has been rarely observed in Caucasians but was reported at higher prevalence among African-Americans. We report on the molecular basis of C6D in seven unrelated black individuals of North or Central Africa descent who live in France. These patients have presented Neisseria meningitidis infection (four cases), focal and segmental glomerulosclerosis with hyalinosis (one case), systemic lupus erythematosus (one case) or Still's disease (one case). All patients exhibited undetectable antigenic C6 by using a sensitive ELISA assay. An additional four cases of complete C6 deficiency with no associated disease have been characterized after family studies. Exons 6, 7 and 12 have been described recently as the location of molecular defects on the C6 gene in randomly chosen black Americans. Genomic DNA from the seven patients were subjected to direct polymerase chain reaction amplification of these three exons. Nucleotide sequencing analysis of the amplified DNA fragments revealed a homozygous single-base deletion (1936delG) in exon 12 in three cases and four compound heterozygous deletions for a single base in exon 7 (1195delC) or in exon 6 (878delA) associated with the same deletion in exon 12 (1936delG). Our observations further establish the restricted pattern of genetic defects associated with homozygous C6 complement deficiency in individuals of African descent.

Adolescent↗
PubMed1998

Human complement factor H deficiency associated with hemolytic uremic syndrome.

This study reports on six cases of deficiency in the human complement regulatory protein Factor H (FH) in the context of an acute renal disease. Five of the cases were observed in children presenting with idiopathic hemolytic uremic syndrome (HUS). Two of the children exhibited a homozygous deficiency characterized by the absence of the 150-kD form of Factor H and the presence, upon immunoblotting, of the 42-kD Factor H-like protein 1 (FHL-1) and other FH-related protein (FHR) bands. Southern blot and PCR analysis of DNA of one patient with homozygous deficiency ruled out the presence of a large deletion of the FH gene as the underlying defect for the deficiency. The other four children presented with heterozygous deficiency and exhibited a normal immunoblotting pattern of proteins of the FH family. Factor H deficiency is the only complement deficiency associated with HUS. These observations suggest a role for FH and/or FH receptors in the pathogenesis of idiopathic HUS.

Acute Disease↗
PubMed1997

Combined heterozygous deficiency of the classical complement pathway proteins C2 and C4.

Genetic deficiencies of components of the classical pathway of complement activation are associated with an increased risk for the development of autoimmune and immune complex-mediated diseases. In the present study we report on the molecular and clinical features associated with combined heterozygous C4 and C2 deficiency in 15 individuals investigated within six families. Approximately 30% of the individuals manifested SLE or another autoimmune condition. Heterozygous C2 deficiency was related to a 28-bp deletion in the C2 gene (C2 deficiency type I), in most cases within the HLA-A25 B18 C2Q0 BfS C4A4B2 DR2 haplotype. Among 13 partial C4-deficient haplotypes transmitted, 8 carried C4A*Q0 alleles and 5 C4B*Q0 alleles. In seven cases the C4A*Q0 alleles were associated with a deletion of the C4A/CYP21P genes within the HLA-B8 C2C BfS C4AQ0B1 DR3 haplotype. In three cases, the C4B*Q0 allele was associated with a deletion of the C4B/CYP21P genes within the HLA-B18 C2C BfF1 C4A3BQ0 DR3 haplotype. In the other cases, C4A*Q0 or C4B*Q0 was dependent on as yet uncharacterized defects in the C4 gene or in C4 gene expression. In view of the relatively high frequency of heterozygous C4 deficiency in the normal Caucasian population, the expected frequency of the combined deficiency should approximate 0.001.

Adult↗
PubMed1994

Complete inherited deficiency of the fourth complement component in a child with systemic lupus erythematosus and his disease-free brother in a north African family.

Although null alleles of complement C4 genes (C4A*Q0 and C4B*Q0) are frequent in the normal population, the occurrence of two null alleles on the same chromosome is very rare and therefore complete C4 deficiency is exceptional. We describe a 16-year-old North African boy who presented with systemic lupus erythematosus with renal involvement and persistent undetectable classical pathway activity and C4 protein and hemolytic activity in plasma, with normal C3 levels. Similar complement abnormalities were observed in his healthy 12-year-old brother. Complete C4 deficiency was documented in the two brothers by investigation of the family and the lack of C4A and C4B bands upon phenotyping of C4. Southern blot analysis of the C4/CYP21 gene organization in the family indicated that the deficiency resulted from a deletion of the C4B/CYP21A genes associated with nonexpression of a C4A gene. The double-null haplotype was found to be associated with homozygous A2 B17 C2C BFF C4 AQ0 BQ0 DR7 HLA haplotype. Thus, similar C4 deficiencies with HLA identity may lead to different clinical presentations.

Adolescent↗