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R Fauchet

Publications and source records attributed to R Fauchet.

At least 19 recordsLinked to original sources
PubMed1992

Effect of an anti-HLA class I monoclonal antibody on the antigenic and transcriptional expression of HLA class I genes in U937 cells.

The phenomenon of antigenic modulation was studied in the histiocytic lymphoma line U937. A redistribution of cell surface HLA antigen after incubation of U937 cells with the monomorphic anti-HLA class I monoclonal antibody W6/32 was demonstrated by immunofluorescence analysis. As assessed by hybridization of RNA obtained from W6/32-treated U937 cells with a probe corresponding to the alpha 3 domain of HLA Cw3, prolonged W6/32 incubation (24 to 72 hours) induced a decrease in HLA class I transcript abundance. This decrease was about 25% as compared with untreated control cells. These data indicate that W6/32 incubation can induce changes in HLA class I gene expression not only at the antigenic but also at the transcriptional level. Possible implications for the molecular basis of antigenic modulation are discussed.

Antibodies, Monoclonal↗
PubMed1992

DPB1 polymorphism in rheumatoid arthritis: evidence of an association with allele DPB1 0401.

HLA-DP polymorphism was examined in 71 rheumatoid arthritis patients and 148 controls, using dot-blot analysis with 14 synthetic oligonucleotide probes specific for the variable region of the DPB1 second exon. The DPB1 0401 allele was found to be significantly more frequent in RA patients than in controls (77.46% vs 55.40%, p less than 0.002, pc less than 0.03, relative risk value: 2.74). An association between DPB1 0401 and seropositivity for rhumatoid factors was also observed: 44 of the 55 seropositive RA patients were DPB1 0401 (p less than 0.001). Analyzing the HLA DPB1 alleles frequencies in 57 HLA-DR-typed RA patients did not show any linkage between the DPB1 0401 and the DR4 specificities. Furthermore, the DPB1 0401 homozygous frequency was increased in DR4-negative RA patients. Our findings suggest an independent role of the DPB1 0401 allele in the genetic susceptibility to RA.

Adult↗
PubMed1992

No major monoclonal lymphocyte population in the thyroid of patients with Graves' disease: study of gene rearrangement by restriction fragment length polymorphism and polymerase chain reaction.

The present study aimed at determining the mono-, oligo-, or polyclonal nature of intrathyroid lymphocytes at the DNA level in patients with Graves' disease. Two techniques were used to seek monoclonal rearrangement in DNA derived from intrathyroidal lymphocytes obtained from six patients. The first was restriction fragment length polymorphism using two specific probes from the B-chain of T-cell receptor and the other from the heavy chain immunoglobulin gene; the second was polymerase chain reaction using a couple of specific primers from the variable and joining regions of heavy chain immunoglobulins. The results for the patients with Graves' disease were compared with those obtained for circulating T-and B-lymphocytes, granulocytes (negative controls), and T- and B-leukemic cells (positive controls). The results with restriction fragment length polymorphism favored a polyclonal origin for the lymphocytes in all cases, since no rearrangement was visualized. The results with polymerase chain reaction were analogous, and the technique was 10 times more sensitive in the detection of rearrangement.

Adult↗
PubMed1992

Polycythaemia and portal vein thrombosis.

An attempt was made to discover the aetiology of acquired portal vein thrombosis in 12 polycythaemic patients who did not show any obvious local or regional cause. In addition to the diagnostic criteria of polycythaemia vera, erythropoietin was determined and cultures of erythroblast precursors were examined. The patients could be divided into 3 groups, in the first of which the definite diagnosis of polycythaemia vera was made on the basis of the PVSG (Polycythaemia Vera Study Group) criteria and bone marrow biopsy (5 patients). In the second group (5 patients), there was a diagnosis of possible polycythaemia vera based essentially on the finding of a spontaneous growth of medullary CFU-E. Finally, diagnostic criteria for polycythaemia vera were absent in two patients. On the basis of these findings, the physiopathology of the association of portal thrombosis and polycythaemia is discussed, in particular polycythaemia secondary to hepatic ischaemia.

Adult↗
PubMed1991

Transfected trophoblast-derived human cells can express a single HLA class I allelic product.

The human trophoblast-derived JAR cell line, that does not express polymorphic HLA class I antigens even after IFN induction, can be stably transfected by genomic clones encoding the entire HLA-A2, -A3 and -B7 alpha-chain genes. The transfected genes were expressed at the cell surface in association with endogenous beta 2-microglobulin (shown by FCM analysis) as a single allelic product without reexpression of any endogenous class I gene (shown by 1D.IEF analysis). Furthermore, TNF-alpha and IFN-gamma, alone and synergistically, increase cell surface expression of transfected MHC class I/endogenous beta 2m heterodimers without induction of endogenous class I alpha-chain genes. These data show that the MHC class I-negative JAR human cell line might be used for transfections with the aim of establishing human cells expressing just one defined MHC class I allele for functional and regulatory studies. These findings are discussed in relation to the methylated status solely of endogenous class I alpha-chain genes in JAR cells and suggest that transfected class I genes are not regulated in the same fashion and, in particular, that constitutive and TNF/IFN inducible trans-acting regulatory factors able to bind to cis-promoter/enhancer sequences of class I DNA are likely to be present.

Alleles↗
PubMed1991

Aspartic acid at position 57 of the HLA-DQ beta chain in insulin-dependent diabetes mellitus: an association with one DRw9-DQw9 subtype in the Chinese population.

Eighteen unrelated Chinese patients with insulin-dependent diabetes mellitus (IDDM) were analyzed for HLA Class II genes using a variety of molecular biological techniques including restriction fragment length polymorphism (RFLP), polymerase chain reaction with allele-specific oligonucleotides (PCR-ASO) and direct DNA sequencing. The high frequency of DR3/DR4 heterozygotes found in the Chinese with IDDM strengthens the importance of this combination of haplotypes in IDDM susceptibility since it is present in two genetically distant populations--Chinese and Caucasians. The frequency of DRw9, a rare allele in the Caucasian population, is much higher in the Chinese. Moreover, the DQ beta chain linkage of DRw9 was different in IDDM patients compared with control subjects. In contrast with previous results, codon 57 of the DQ beta chain was aspartic acid in DRw9 Chinese IDDM patients. Furthermore, one particular DRw9-DQw9 haplotype may be associated with IDDM susceptibility in the Chinese population.

Alleles↗
PubMed1991

[A focus of multiple sclerosis in Bretagne: HLA markers and evaluation of consanguinity].

In a previous study, we established the overall prevalence of multiple sclerosis at 25 per 100,000 inhabitants in the French province of Brittany and found that the geographical distribution was uneven with four circumscribed high prevalence areas with more than 45 per 100,000. We conducted the present study to try to ascertain whether the existence of such clusters of MS could be explained by genetic factors, using two ways: the major histocompatibility markers and the frequency of intermarriage. Among the four areas of high prevalence, we examined the one with the highest prevalence, exempt from migratory movements over the last 100 years. We compared this studied population to a sample of 1005 healthy unrelated individuals coming from all over Brittany, designated as general Brittany population. A large sampling (about 25%) of the population accepted to take part in the study. Regarding HLA markers, we observed in the high prevalence area an increases percentage of B7, B8, B12, DR4 and a decreased percentage of B5, compared with the Brittany control population. The consanguinity coefficient in the population of high MS prevalence area was steadily much higher than the one in neighbouring areas with a low MS prevalence during a long period from 1896 to 1945. Under the reserve of non-randomized sampling of individuals for HLA marker study, our findings yielded a double argument in favor of genetic factors influencing the presence of clusters of MS cases: the particularities of HLA phenotype pattern and the increased consanguinity coefficient. The particularities of HLA polymorphism observed in the high prevalence area are likely to be the consequence of the intermarriage habits of this population.

Adult↗
PubMed1990

HLA class I gene polymorphism in genetic hemochromatosis.

The authors have studied HLA class I polymorphism in an attempt to identify a genomic marker of the hemochromatosis gene. Five enzymes were used (HindIII, EcoRI, EcoRV, PvuII, and HincII) in 47-106 unrelated patients and 71-91 controls. Both populations were HLA-typed. The relationship between the restriction fragments and HLA-A antigens was considered. Comparison of the two groups revealed a significantly high frequency of one 14 kb EcoRI fragment among the HLA-A3 hemochromatosis patients. The fragment hybridizes to an HLA-A specific probe but not to an HLA-B specific probe, and is associated with the hemochromatosis gene, which is itself associated with HLA-A3.

HLA Antigens↗
PubMed1990

Implication of the HLA-DRB3 gene in Graves' disease: predominance of allele Dw24.

Using RFLP, the present study sets off to determine the MHC class II gene polymorphism in Graves' disease, in order to define the HLA-related genetic susceptibility. Considering the preferential link between Graves' disease and the HLA-DR3 antigen, 42 HLA-DR3 Graves' disease patients were studied and compared with 42 HLA-DR-matched controls. Hybridization with a DQ alpha probe of DNAs digested by Taq I revealed a polymorphism of the DR3 haplotype with an overrepresentation of a 2.1 kb(U) fragment in patients, but this was merely a sign of the linkage disequilibrium between U and B8DR3. Hybridization with the DR beta probe of DNAs digested by Taq I yielded more facts. It revealed the overrepresentation of the Dw24 specificity (Taq I:9.8 kb) in DR3 Graves' disease patients. This study thus enabled us to determine precisely the susceptibility linked to the DR3 haplotype, implicating the DRB3 gene and its Dw24 allele, which appear to be the most reliable markers of the disease, providing a higher relative risk than B8DR3.

Alleles↗
PubMed1990

Antithyroid drugs and Graves' disease: a prospective randomized evaluation of the efficacy of treatment duration.

A prospective randomized study was performed in patients with hyperthyroid Graves' disease (GD) in order to compare long (18 months) and short term (6 months) antithyroid drug treatment on the remission rate. A therapeutic protocol was offered to all GD patients who had not been treated for this disease previously. All patients studied who followed the protocol were rechecked 2 yr after treatment was withdrawn, or earlier in the case of relapse. Of the patients having undergone long term treatment, 61.8% still were in remission 2 yr after treatment withdrawal, whereas only 41.7% of the patients treated for 6 months were in remission (P less than 0.05). Such findings clearly establish that treatment duration has a direct beneficial incidence on the remission rate. These results were confirmed by the fact that treatment for 18 months resulted in remission in 7 of 15 patients who had previously relapsed after a 6-month course of therapy. This improvement in relation to treatment duration might be due to the immunosuppressive action of carbimazole. No significant difference was observed between relapse and remission groups, regardless of treatment duration, for HLA ABDr, serum T3 and T4, and T3/T4 ratio determined before treatment. Only the thyroid-stimulating antibody levels determined at the time of diagnosis and at the end of treatment were higher in the relapse group, a difference that was relevant only globally, due to value scattering. Furthermore, thyroid-stimulating antibody levels at the end of treatment may indicate remission or, conversely, continuance of the pathological process.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Genetic polymorphism of alpha-L-fucosidase in Brittany (France).

The authors studied the phenotypic distribution of alpha-L-fucosidase in a random sample of the population of the area of Rennes (France). The frequencies of Fu1 (0.64) and Fu2 (0.36) genes are significantly different from the frequencies observed in New York whites and blacks.

Adolescent↗
PubMed1979

Serum ferritin as a possible marker of the hemochromatosis allele.

To determine whether a correlation exists between the biochemical expression of hemochromatosis and the HLA genotype, we studied 174 family members of 32 persons with the disease. Persons who shared both HLA haplotypes with the proband (and presumably having two hemochromatosis alleles) differed significantly from those who shared only one haplotype (and presumably having one hemochromatosis allele) in terms of serum iron (P less than 0.001 for both sexes), unsaturated iron-binding capacity (P less than 0.01 for female and P less than 0.0001 for male subjects) and serum ferritin (P less than 0.0001 for female and P less than 0.00001 for male subjects). The only significant difference between relatives having one hemochromatosis allele and age and sex-matched controls was related to serum ferritin values in male subjects (P less than 0.05, despite considerable overlap). In our hands, serum ferritin was the best indicator of disordered iron metabolism and was elevated among most homozygous but among few heterozygous family members.

Adolescent↗
PubMed1979

[Demonstration by iron overloading study and HLA genotyping of recessive transmission of idiopathic haemochromatosis in two pseudodominant pedigrees (author's transl)].

We studied iron overloading and HLA genotype in two families with overt forms of idiopathic haemochromatosis in two successive generations. In each family the spouse of the patient with overt haemochromatosis in the first generation had clinical and laboratory signs of moderate iron overload and a HLA haplotype A3, B14 and A3, B7 respectively--which is frequently associated with the haemochromatosis gene. This specific HLA haplotype had been transmitted to the second generation patient with overt disease, which thus could be considered as having received a haemochromatosis gene from each parent. Although the finding of cases of overt disease in successive generation firstly suggests a dominant transmission the genetical analysis of these families lead to further strong argument in favour of recessive inheritance of idiopathic haemochromatosis.

Adolescent↗
PubMed1979

HLA determinants in idiopathic hemochromatosis.

HLA-A and B antigens were defined in 154 unrelated idiopathic hemochromatosis patients. The study confirmed the highly significant positive association with HLA antigens A3 (corrected P less than 10(-10)) and B14 (corrected P less than 10(-9)). HLA-DR typing showed increased frequency of the specificity DRw6, which was frequently associated with the phenotype A3, B14 and antigen B14, suggesting linkage disequilibrium. This was borne out by PLT data.

Epitopes↗