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H Betuel

Publications and source records attributed to H Betuel.

At least 37 records · Page 2Linked to original sources
PubMed1991

[HLA-A29 sub-types and "Birdshot" choroido-retinopathy susceptibility: a possible "resistance motif" in the HLA-A29.1 molecule].

The Birdshot choroidoretinopathy (BSCR) is an ocular disease strongly associated with HLA-A29. The HLA-A29 specificity can be split using immunoelectrofocusing in two subtypes A29.1 and A29.2. BSCR susceptibility is exclusively linked to the HLA-A29.2 molecule. The sequence of HLA-A29.2 was established (EMBL X60108 and found to be identical between patients and healthy individuals. A single difference was found (H----D) 102) in the extra cellular domains between HLA-A29.2 and HLA-A29.1. The HLA-A29 sub-types shares the consensus HLA class I sequence (D102). The mutation exhibited by HLA-A29.1 (H102) is unique to that molecule. The ancestral type is thus HLA-A29.2 that confers the susceptibility to BSCR whereas HLA-A29.1 has arisen from a more recent mutation conferring resistance to BSCR. Another single amino-acid difference between HLA-A29.1 and HLA-A29.2 was found in the intracytoplasmic part of the molecule, HLA-A29.2 exhibiting the HLA-A consensus sequence whereas A29.1 shares with AW33.1 the mutation S----F321. In addition, the A29 specificity was assigned to L and Q amino-acids at position 62-63, which can interact with peptides into the binding groove. No specific T or B epitope of susceptibility could be considered involving the region of the mutation discriminating HLA-A29.2 from HLA-A29.1. The HLA-A29.1 mutation is unable to interact with the T cell receptor and did not seem to induce significant structural changes in the peptide-binding groove. Conversely, its position suggests that the A29.1 mutation might interfere with the binding of an accessory molecule, the CD8 molecule being the most likely candidate for that role.

Amino Acid Sequence↗
PubMed1989

HLA antigens and infertility with sperm autoantibodies in man.

Vasectomized men with sperm auto-antibodies (S.A.A.) and high frequency of HLA-A20 antigen (Ag) were observed by Law et al. (1979); Hancock et al. (1983) observed the prevalence of HLA-A28 in infertile men with S.A.A. HLA-A, B and DR Ag were determined in a population of 80 Caucasian infertile men with (n = 22) or without (n = 58) agglutinating and/or cytotoxic S.A.A. in serum (S) and/or seminal plasma (SP), and the association between HLA-determinants and infertility with S.A.A. was investigated. The frequence of HLA-A28 Ag was found higher in the group with S.A.A. than without (18.2% vs 0.0%) but not statistically significant (chi 2 = 8.87; pc less than 0.15). The same result was obtained with HLA-B13 Ag (chi 2 = 8.87; pc less than 0.32). Lastly, there was no prevalence of HLA-DR Ag in men with S.A.A. In conclusion, no association was found between HLA-A, B and DR Ag and infertility with S.A.A. Nevertheless, two HLA-Ag were more frequently observed in the group with S.A.A.

Adult↗
PubMed1989

Gene conversions and rearrangements cause discordance between inheritance of forms of 21-hydroxylase deficiency and HLA types.

Congenital adrenal hyperplasia (CAH) can be caused by a variety of defects in the functional gene encoding 21-hydroxylase (P450c21), which lies in the midst of the human leukocyte antigen (HLA) locus on chromosome 6. As a result, Mendelian genetics permit clinically distinct forms of CAH to be traced genetically by HLA and complement typing of family members. The recent cloning of probes for P450c21 now permits tracing of the affected gene directly. A consanguineous family had three members affected with three clinically distinct forms of CAH. Two of these individuals had identical extended haplotypes, including nine HLA and complement loci. Despite this extensive identity, the patterns of genomic DNA fragments digested with endonuclease EcoRI and detected by a P450c21 cDNA probe differed greatly in these two individuals. Thus, the DNA diagnosis of allelic variation was much more sensitive than the HLA diagnosis. Genomic DNA digested with endonuclease TaqI and probed with P450c21 cDNA revealed the 3.2-kilobase (kb) band, which is generally associated with the nonfunctional P450c21 A pseudogene, in all family members, and also revealed the 3.7-kb band associated with the functional P450c21 B gene in all family members except the severely affected index case. Probing of the same blots with a genomic probe also permitted examination of the adjacent downstream TaqI fragments, showing retention of both the 2.4-kb (A pseudogene) and 2.5-kb (B gene) fragments. Similarly, BglII-digested genomic DNA from all individuals contained both the 12-kb (A pseudogene) and 11-kb (B gene) bands. These data indicate that the basis of 21-hydroxylase deficiency in the index case was due to a homozygous gene conversion event and not to gene deletion. These results show that the DNA in and around the 21-hydroxylase gene is genetically very active, so that the usual generalization concerning linkage and inheritance may yield incorrect conclusions and diagnoses.

Adolescent↗
PubMed1989

Kidney-graft survival in simultaneous kidney-pancreas transplantation.

Patient and kidney survival rates were compared between 69 diabetic patients undergoing simultaneous kidney-pancreas transplantation (group 1) and 723 nondiabetic patients undergoing kidney transplantation (group 2). The patients were treated with different immunosuppressive regimens over the years: steroids plus antilymphocyte globulin (ALG) plus azathioprine (Aza); cyclosporin A (CsA) plus ALG; steroids plus ALG plus Aza, replacing Aza 1 mo posttransplantation; or low doses of steroids plus CsA plus Aza. One-year kidney survival rates with the different regimens were 50, 42, 54, and 76%, respectively, in group 1 and 71, 74, 78, and 84%, respectively, in group 2. Patient survival was 60, 57, 71, and 86%, respectively, in group 1 and 93, 95, 94, and 96%, respectively, in group 2. Differences between the two groups were statistically significant for the first three protocols but not for the one used in this study. In group 1, 38 patients (55%) had a functioning kidney graft, whereas 15 (21%) lost their kidney to rejection. Between these two patient categories, there was no significant difference in age, sex, duration of diabetes, time on dialysis, blood transfusion number, HLA immunization, or HLA matching. Thus, since 1984, kidney-graft survival has not been inferior in diabetic patients. This improvement is mainly due to a decreased mortality related to better patient preparation and improvement in immunosuppression.

Graft Survival↗
PubMed1989

Epstein-Barr virus associated lymphoproliferative diseases (B cell lymphoma) after transplantation.

We report 12 cases of lymphomas which occurred among 1670 patients with kidney or combined renal and pancreatic transplantation. Group 1 comprised nine patients presenting with the diffuse form of the disease where immunoblasts or mature plasma cells massively infiltrated all organs. The first symptom was a viral syndrome, associated with a restriction of heterogeneity of immunoglobulins; oligoclonal to monoclonal peaks of immunoglobulins appeared about 50 days after transplantation. All patients received antilymphocyte globulins (ALG), and seven were treated with cyclosporin. EBV infection could be demonstrated in almost all patients; three EBV lymphoblastoid cell lines were established, their HLA phenotype being the same as the recipient of the graft. All patients finally died with renal and hepatic failure. Group 2 comprises three patients who presented solid B cell tumours of tonsils, lungs, and spleen at onset, extending to liver, kidney graft, lymph nodes, and brain. All received cyclosporin; two patients were treated with ALG, and one with OKT3. Immunoglobulins were polyclonal, oligoclonal, or decreased. Cell surface immunoglobulins were monoclonal on two tumours. EBV-DNA was positive within two tumours. Two patients presented EBV and CMV primary infection. CD4+T lymphocytes subsets were diminished at onset, and increased after cessation of immunosuppressive therapy. One patient died because of brain involvement; the two others are alive, one with perfect graft function. Therapy consisted of stopping immunosuppressive treatment, Acyclovir, and in two patients of group 2, monoclonal antibodies to pan-B and EBV receptor antigens.

Acyclovir↗
PubMed1989

Renal transplantation at the University of Lyon.

Over the last 23 years, progress in renal transplantation has dramatically decreased mortality and transplant failures, especially during the first years following the transplant. Further improvement in immunosuppression or in induction of specific unresponsiveness should, in the future, limit the incidence of late failures. More experience in transplantation has led to reduced frequency and severity of most complications. This has resulted in acceptance of patients with risk factors such as old age or infancy, poor vascular status, hyperimmunization, or requirement for several transplants (kidney + pancreas, kidney + heart, kidney + liver, etc.). Optimum organ procurement facilities will be required to meet the increased demand for kidney transplants. It is hoped that this need will be stabilized when late transplant failures will become infrequent, thus decreasing the requirements for retransplantation.

Blood Transfusion↗
PubMed1989

[Immunogenetics of Horton's disease and of rhizomelic pseudo-polyarthritis].

The etiopathogenesis of temporal arteritis and rhizomelic pseudo-polyarthritis still remains undefined. A genetic predisposition would seem probable in view of epidemiological data (higher frequency in white caucasian races and in certain countries), the existence of rare familial forms (25 families reported), and the significant increase in incidence in unconnected cases with HLA DR4 antigen (6 studies). Environment may intervene as a precipitating factor in the condition and the role of an infectious agent, to account for the seasonal incidence of this disorder and the rare existence of cases in non consanguineous couples, has been suggested but remains unproven. Disordered immune function probably plays an essential role in the creation of the vascular histological lesions characteristic of the condition. The disordered function involves cellular immunity (fall in OK T8. in blood) and especially humoral immunity with the very frequent presence of circulating immune complexes in the serum and deposition of immunoglobulins and complement at arterial wall level.

Antibody Formation↗
PubMed1988

Autoreactive T cell clones specific for class I and class II HLA antigens isolated from a human chimera.

T cell clones of donor origin that specifically react with recipient cells were obtained from a SCID patient successfully reconstituted by allogeneic fetal liver and thymus transplantation performed 10 yr ago. The majority of these clones displayed both cytotoxic and proliferative responses towards PBL and an EBV-transformed B cell line derived from the patient. In addition, these T cell clones had proliferative and cytotoxic responses towards the parental PBL, EBV cell lines, and PHA blasts. Blocking studies with anti-class I and anti-class II HLA mAbs indicated that the activity of the CD4+ T cell clones was specifically directed against class II HLA antigens of the recipient. On the other hand, the cytotoxic and proliferative responses of the CD8+ T cell clones were specific for class I HLA antigens which are ubiquitously expressed on the recipient cells. Thus, the establishment of transplantation tolerance observed in this stable human chimera is not due to the elimination of host-reactive T cells from the repertoire and suggests the presence of a peripheral autoregulatory suppressor mechanism.

Child↗
PubMed1988

HLA-DQ rather than HLA-DR region might be involved in dominant nonsusceptibility to diabetes.

Since HLA-DRw15 (a subdivision of the HLA-DR2 specificity previously called DR2 long) is associated with dominant nonsusceptibility to insulin-dependent diabetes mellitus (IDDM), while HLA-DRw16 (another subdivision of HLA-DR2, previously called DR2 short) is positively associated with the disease, we looked for particular characteristics of HLA products encoded by the DR2 haplotypes of IDDM patients. The results show the following: (i) HLA-DQ molecules of HLA-DRw15-positive IDDM patients are different from those of HLA-DRw15-positive controls, suggesting that the HLA-DQ gene of DRw15 haplotypes is involved in a protective effect. (ii) HLA-DR and -DQ products of DRw16-positive IDDM are functionally indistinguishable from those of HLA-DRw16-positive controls. Furthermore, our data provide evidence that the residue at position 57 on the DQ beta chain could play a crucial biological role in antigen presentation to T cells as far as the DRw16 haplotype is concerned. This observation fits with the recent observation of correlation between DQ beta allelic polymorphism at position 57 and both susceptibility and resistance to IDDM.

Amino Acid Sequence↗