Polymorphism of the HLA90 new class I gene.
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Base Sequence↗
Biomedical subjects
R Fauchet
Publications and source records attributed to R Fauchet.
P-glycoprotein (P-170) and CD34 expression in adult acute myeloid leukemia (AML).
We investigated the prognosis value of CD34 and P-170 expression in blast cells of adult patients affected by de novo acute myeloid leukemia (AML). CD34 antigen was analyzed by indirect immunofluorescence (IFI) and alkaline phosphatase-labeled streptavidin biotine (AP-LSAB) in 62 patients (median age: 51 years). P-170 expression was determined by AP-LSAB in 51 cases using JSB1 and C219 monoclonal antibodies. All patients were treated with conventional chemotherapy induction regimen. Follow-up was from 6 to 79 months. Complete remission (CR) rate was not statistically different between CD34+ and CD34- patients (67 vs. 84%, p = 0.2). The duration of CR and survival were not influenced by CD34 expression. Karyotype abnormalities were more frequent among MDR+ patients (65 vs. 21%, p < 0.01). CR rate was statistically lower in MDR+ patients as compared to MDR- patients (63 vs. 96%, p = 0.01). Median disease-free survival (DFS) was shorter for MDR+ patients but the difference was not significant (5 vs. 10 months, p = 0.09). Patients who were positive for both parameters CD34 and P-170, had a poor prognosis with a 50 vs. 100% CR rate for CD34/P-170 negative patients, (p = 0.002), a lower median DFS (3 vs. 12 months, p = 0.01) and overall survival (OS) (3 vs. 14.5 months, p = 0.01). Results of cytogenetic analysis did not influence CR rate but the relapse rate was higher, although not significant, for the patients with unfavorable karyotype (63 vs. 33%). The seven CD34+/MDR+ patients with poor prognosis karyotype had a statistically lower CR rate, median DFS and OS than the 7 CD34-/MDR- patients with normal or favorable karyotype (CR: 29% vs. 100%, p = 0.02), (DFS: 3 vs. > 12 months, p = 0.01), (OS: 4 vs. > 12 months, p = 0.02). Our data indicate that P-170 but not CD34 expression is predictive for a lower CR rate. The identification of a bad prognosis subgroup of CD34+/MDR+ AML patients (and especially those with poor prognosis karyotype) has to be confirmed on larger series using uniform methodology.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Expression of the multidrug resistance-associated P-glycoprotein (P-170) in 59 cases of de novo acute lymphoblastic leukemia: prognostic implications.
Immunocytochemical detection of the multidrug resistance (MDR)-associated membrane protein (P-170) was performed at time of diagnosis in a series of 36 children and 23 adults with acute lymphoblastic leukemia (ALL) using two monoclonal antibodies JSB1 and C219. Immunophenotypes were obtained in all cases and karyotypes were analyzed in 37 cases. Detection with JSB1 or with C219 led to similar results in terms of positive cells and cases, but the intensity of staining was higher with JSB1. In the populations studied, the rate of first complete remission differed between MDR-positive and MDR-negative in adult patients only (56% v 93%, respectively, P = .05). Of the 16 MDR-positive patients who had presented a first complete remission, 13 (81%) relapsed, compared with 13 of 35 (37%) MDR-negative (P = .008) patients. A higher rate of relapse among MDR-positive compared with MDR-negative patients was observed in adults and in children taken separately (adults 100% v 46%; children 73% v 32%, respectively). The survival rates (Kaplan-Meier method) were significantly higher in MDR-negative compared with MDR-positive populations as a whole (P = .002) and among children (P = .05) and adults (P = .03) taken separately. Event-free survival curves followed this trend. The percentage of second complete remission was very low in the MDR-positive group (15%) compared with 38% for the MDR-negative group. These results were shown by multivariate analysis to be independent of age, immunophenotypes, and karyotypes and clearly show the importance of MDR phenotype detection in ALL.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
HLA-E is the only class I gene that escapes CpG methylation and is transcriptionally active in the trophoblast-derived human cell line JAR.
Polymorphic as well as HLA-F and -G genes are repressed in the human cell line JAR, derived from a tumor of trophoblast origin. By contrast, the HLA-E gene as well as the non-HLA novel coding-sequence, R1, located 5' to HLA-E, both remain transcriptionally active. We first demonstrated the role of DNA methylation in the repression of class I genes (except HLA-E) in JAR by the use of the 5-Azacytidine demethylating agent. Following treatment, JAR clones reexpressed polymorphic class I transcripts and cell surface alpha chains. Using methylation-sensitive rare cutter enzymes on JAR genomic DNA, followed by classical or pulse field gel electrophoresis and hybridization with HLA locus-specific probes, we found methylated CpG islands in the 5' region of all class I genes, except for HLA-E. These results, establishing an inverse relationship between states of methylation and transcriptional activity within the MHC class I chromosomal region in JAR, and the observations that the HLA-E and R1 genes were ubiquitously expressed, suggest that the HLA-E chromosomal domain might have functional importance including the presence of housekeeping genes.
Azacitidine↗
Detection of P glycoprotein activity on normal and leukemic CD34+ cells.
Rhodamine 123 is transported by the transmembrane efflux pump P glycoprotein (Pgp). We used this fluorescent dye to study multidrug resistance (MDR) activity in normal and leukemic CD34+ cells. These immature cells had a high degree of MDR activity. Among leukemic cells, CD34+ leukemias had significantly higher MDR activity as compared to CD34- leukemias. Heterogeneous results in cell subpopulations, however, indicate that prognosis should be interpreted in the light of MDR analysis.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Evidence for a polymorphism of HLA-G gene.
HLA-G gene polymorphism was analyzed by RFLP using seven restriction enzymes and an HLA-G locus-specific probe. Hybridization of 55 DNAs digested with three enzymes (Taq I, Pst I, and Bgl II) revealed two polymorphic bands in each case. RFLP patterns obtained with Taq I and Pst I corresponded to the same allelic polymorphism and differed from the Bgl II polymorphism. Combining both polymorphisms enabled determination of four alleles. Allelic frequencies were calculated: 40% of the subjects tested had allele 1, 36% had allele 2, 22% had allele 3, and 2% had allele 4. Analyzing the complete HLA class I phenotype revealed strong linkage disequilibrium with the HLA-A locus. The polymorphism described is located in the 3' flanking region of the gene. Moreover, extended HLA-A haplotypes were constructed by combining the HLA-G polymorphism with other class-I-sequence polymorphisms.
Base Sequence↗
A new probe detecting HLA-8 gene polymorphism.
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Alleles↗
HLA-DR and -DQ genotyping by PCR-SSO in Shanghai Chinese.
The polymorphism of HLA class II (HLA-DRB1, -DQA1 and -DQB1) were investigated in 89 Shanghai Han Chinese using polymerase-chain reaction amplification and oligonucleotide (PCR-SSO) typing. Of the 43 DRB1 alleles tested, 24 were observed. DRB1*0901 (16.85%), *0803 (9.55%), *1202 (9.55%) and *1501 (12.92%) were most frequent and account for the high frequencies of DR9, DR8, DR5 and DR2 specificities in this population. The alleles DRB1*0101, *0102 and *1001 had very low frequencies. Among the 8 DQA1 and 13 DQB1 alleles tested, only DQA1*0401 and DQB1*0402 were absent. DQA1*0301, and DQB1*0301 and *0303 were among the most common alleles of the two loci respectively. Unusual DRB1-DQA1-DQB1 haplotypes were observed and a DRB1 "new" allele was suggested.
Alleles↗
Differences between human sperm and somatic cell DNA in CpG methylation within the HLA class I chromosomal region.
PROBLEM: We investigated the possible negative regulatory mechanisms that repress classical human leukocyte antigen (HLA) class I gene expression in human spermatozoa and searched for novel testis-specific coding sequences that might be present in MHC class I chromosomal region. METHOD: We performed a comparative DNA methylation analysis of this genomic region in both purified human spermatozoa and mononuclear blood cells from the same donors, using methylation-sensitive restriction enzymes followed by classical or pulsed field gel electrophoresis and hybridization with HLA class I locus-specific probes. RESULTS: Unmethylated CpG sites were detected in the 3' part of HpaII tiny fragments of the HLA-F and HLA-G genes in spermatozoal DNA. In contrast, no difference was observed in the methylation status of the HLA-B, HLA-C, and HLA-E genes between germ and somatic cells. CpG unmethylation events were also detected in several parts of this chromosomal region (outside the known loci) in spermatozoal DNA. CONCLUSIONS: These results suggest that this genomic region undergoes changes in its DNA methylation pattern during the developmental process. We hypothesize that these dynamic changes have functional importance, including a possible transcriptional activity of nonclassical class I genes and/or as yet undescribed testis-specific coding sequences.
Base Sequence↗
[Autoimmune hemolytic anemia. Etiology, diagnosis, treatment].
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Anemia, Hemolytic, Autoimmune↗
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↗
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↗
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↗
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↗
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↗
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↗
Genetic susceptibility linked to DR4 haplotypes in diabetes of type-1a or associated with polyendocrinopathies (type-1b). The Diabetes Study Group from West France.
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Alleles↗
[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↗