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M Abbal

Publications and source records attributed to M Abbal.

At least 55 records · Page 3Linked to original sources
PubMed1997

Genes of the major histocompatibility complex class II influence the outcome of hepatitis C virus infection.

BACKGROUND & AIMS: The host's immune response may influence the course of hepatitis C virus (HCV) infection. The aim of this study was to investigate the distribution of HLA class II alleles in white subjects who spontaneously recovered from HCV infection compared with that in patients with persistent infection. METHODS: HLA-DRB1 and -DQB1 typing were performed in 103 consecutive patients with persistent HCV infection (HCV antibody positive, HCV RNA positive) and in 25 subjects with transient HCV infection (HCV antibody positive, persistently negative HCV RNA). RESULTS: No significant differences between subjects with transient or persistent infection were observed for age, sex, source of infection, or HCV serotype. The frequency of DQB1*0301 and DRB1*1101 alleles was higher in patients with transient infection than in those with persistent infection (84% vs. 30.8%, 40% vs. 9.8%; P < 0.01 and P < 0.02, respectively [Bonferroni correction]). DRB1 and DQB1 alleles did not influence viral load as an independent factor. Mean Knodell's scores were lower in patients with DQB1*0301 allele (6.12 +/- 0.4) than in those negative for DQB1*0301 (7.37 +/- 0.3; P < 0.05). CONCLUSIONS: Our results suggest that host- rather than virus-related factors are probably involved in the spontaneous clearance of HCV.

Adult↗
PubMed1996

Neuroendocrine system and immune responses after confinement.

A confinement experiment in a normobaric diving chamber was undertaken to obtain more understanding of the effects of confinement and isolation on human psychology and physiology. Pre- and post-confinement blood samples were obtained from four test subjects and five control subjects for the analysis of plasma proteins, hormone levels and immune responses. The absence of significant changes in the immune responses correlates with the absence of major changes in neurohormones and other hormones such as cortisol, prolactin, growth hormone, insulin-like growth factor 1, triiodothyronin, thyrotrophin and 1,25-dihydroxyvitamin D. It is increasingly recognized that the immune system is not an independent physiological system, but a system that interacts multidirectionally with other organs and body functions. It seems that the conditions of this confinement experiment were not stressful from a psychological point of view. The presence of a female crew member had probably a positive effect on group behavior of the test subjects. In conclusion, the data suggest that confinement for 60 days in a small habitat without particularly stressful situations has no significant impact on a variety of neuroimmunological parameters.

Adult↗
PubMed1996

Use of bed rest and head-down tilt to simulate spaceflight-induce immune system changes.

Bed rest, both with and without head-down tilt, has been extensively used as an earth-bound analog to study physiologic effects mimicking those occurring in weightlessness during spaceflight. We have been able to show in six subjects that 4 weeks of head-down tilt bed rest induces a significant decrease in interleukin-2 secretion by PHA-stimulated T lymphocytes. Another study, lasting 113 days, with two subjects showed a decreased interleukin-2 receptor expression in PHA-stimulated peripheral blood mononuclear cells but a decreased interleukin-2 production in one subject only. Under the same conditions, interleukin-1 production was largely increased in both subjects. Several other immune parameters were also analyzed. Increased interleukin-1 production could contribute to bone mineral loss encountered during bed rest and decreased interleukin-2 secretion could play a role in the appearance of infectious diseases often observed during bed red.

Antibody Formation↗
PubMed1996

Localization of the recombination points in a family with two DR/DP recombinations.

In a family with a maternal DR/GLO recombination, cellular DP typing showed it to be located between DR and DP. RFLP studies done during the 9th international histocompatibility workshop gave anomalous segregation patterns of DPA and DPB bands that could be interpreted as being due to a second, paternal DR/DP recombination. This assumption was confirmed later by PCR-SSO typing. A more precise mapping has been done by new markers showing the maternal recombination to be within the TAP2 locus and the paternal recombination to be between DQB1 and DQB3. This supports earlier suggestions of a hot spot of recombination in the TAP region. The recombinations involve parental haplotypes that presently show DR/DP linkage disequilibrium in the French population and it is proposed that DR/DP recombinations occur randomly while B/DR recombinations preferentially occur on haplotypes without strong linkage disequilibrium. Existing DR/DP linkage disequilibria in a given population will thus be broken down with time. The mixed lymphocyte culture response towards an isolated DP difference was tested in this and another DR/DP recombinant family. It showed that an alloresponse towards DP may be highly variable and this suggests that it might be important to define the rules for the strength of this reaction and the possible implications for allotransplantation.

Female↗
PubMed1996

Serological markers of autoimmunity in renal transplant patients before and after alpha-interferon therapy for chronic hepatitis C.

Chronic hepatitis C is the major cause of chronic liver disease after successful cadaveric renal transplantation. The aims of this prospective, open study were to assess in such a population, firstly the prevalence of different organ-specific and nonspecific antibodies and related disorders, and secondly their outcome after inteferon-alpha therapy as well as the incidence of new immunologic disorders under and after this therapy. In 15 cadaveric renal transplant patients (10 men, 5 women, ages 29-65 years) with chronic hepatitis C and histological features of chronic active hepatitis, undergoing chronic immunosuppression (ciclosporine A with or without steroid and azathioprine) and treated with recombinant alpha 2b-interferon (IFN alpha) (mean duration 142 +/- 35 days), we assessed before and after this therapy the serum levels of cryoglobulinemia, rheumatoid factors (RF), thyroid-stimulating hormone (TSH), free thyroxine (fT4), and antinuclear (ANA), antismooth muscle (ASMA), antimitochondrial (AMA), anti-LKM1, antimicrosomal thyroid (MCA), antithyroglobulin (TGA) autoantibodies. At the start of IFN alpha therapy, 14 of 15 patients had detectable autoantibodies (RF: 9; ANA > 1/50: 8; ASMA > 1/50: 4; other autoantibodies: 0); 1 had cryoglobulinemia. At the end of therapy the cryoglobulinemia had disappeared, the preexisting autoantibodies remained present in all patients but 2; 3 patients had developed MCA without evidence of clinical or biological thyroid abnormalities and 3 others had developed either RF (1) or ANA (1) or ASMA (1), without any related symptoms. One patient developed transient type II diabetes mellitus without anti-Langerhans beta-cell antibodies. Finally, the occurrence of autoantibodies in our patients was associated either with HLA DR3 or DR4 or DR7 phenotypes. We found that the prevalence of extrahepatic immunologic abnormalities was high in renal transplant patients with chronic hepatitis C and no exacerbation was observed during of after IFN alpha therapy. The most frequent autoantibody appearing after IFN alpha therapy was MCA although without thyroid abnormalities.

Adult↗
PubMed1996

Comparative study of 4 diagnosis criteria sets for mixed connective tissue disease in patients with anti-RNP antibodies. Autoimmunity Group of the Hospitals of Toulouse.

OBJECTIVE: To evaluate the performances of 4 sets of criteria proposed to define mixed connective tissue disease (MCTD): the criteria of Sharp, Alarcón-Segovia, Kasukawa, and Kahn. As anti-U1-RNP antibodies appear indispensable to establish the diagnosis of MCTD, we wished to reevaluate these sets of criteria in patients who all had anti-U1-RNP antibodies. METHODS: We analyzed clinical and biological data to find which diagnostic criteria were met by 45 patients with anti-U1-RNP antibodies. We tested criteria for rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, polymyositis, Sjögren's syndrome, and 4 sets of criteria for MCTD. RESULTS: The criteria that best identified patients with MCTD were those proposed by Alarcón-Segovia, with 62.5% sensitivity and 86.2% specificity, comparable to Kahn's criteria. The overlap with other connective tissue diseases was found to be 16%. These results could be improved by using the term "myalgia" instead of "myositis" in the definition. This increased sensitivity to 81.3%, with no decrease in specificity. CONCLUSION: Alarcón-Segovia's and Kahn's criteria are the best classification criteria to define MCTD.

Adolescent↗
PubMed1995

DQCAR microsatellite polymorphisms in three selected HLA class II-associated diseases.

DQCAR is a very polymorphic CA repeat microsatellite located between the HLA DQA1 and DQB1 gene. Previous studies have shown that specific DQCAR alleles are in tight linkage disequilibrium with known HLA DR-DQ haplotypes. Of special interest was the fact that haplotypes containing long CA repeat alleles (DQCAR > 111) were generally more polymorphic within and across ethnic groups. In these latter cases, several DQCAR alleles were found even in haplotypes containing the same flanking DQA1 and DQB1 alleles. In this work, three HLA class II associated diseases were studied using the DQCAR microsatellite. The aim of this study was to test if DQCAR typing could distinguish haplotypes with the same DRB1, DQA1 and DQB1 alleles in control and affected individuals. To do so, patients with selected HLA DR-DQ susceptibility haplotypes were compared with HLA DR and DQ matched controls. This included: Norwegian subjects with Celiac disease and the HLA DRB1*0301, DQA1*05011, DQB1*02 haplotype; Japanese subjects with Type 1 (insulin-dependent) Diabetes Mellitus and the HLA DRB1*0405, DQA1*0302, DQB1*0401 haplotype; and French patients with corticosensitive Idiopathic Nephrotic Syndrome and the HLA DRB1*0701, DQA1*0201, DQB1*0202 haplotype. These specific haplotypes were selected from our earlier work to include one haplotype bearing a short DQCAR allele (celiac disease and DR3,DQ2-DQCAR99) and two haplotypes bearing long DQCAR alleles (Diabetes Mellitus and DR4,DQ4-DQCAR 113 or 115 Idiopathic Nephrotic syndrome and DR7,DQ2-DQCAR 111-121). Additional DQCAR diversity was found in both control and patients bearing haplotypes with long CA repeat alleles. The results indicate that DQCAR typing did not improve specificity in combination with high resolution DNA HLA typing as a marker for these three disorders.

Base Sequence↗
PubMed1994

Epstein-Barr virus in familial Hodgkin's disease.

Hodgkin's disease (HD) has been found to be linked to Epstein-Barr virus (EBV). Familial HD (FHD) may be related to a possible unknown agent. We have determined whether EBV small RNAs (EBERs) were found in Reed-Sternberg cells from FHD. Five families were studied for histological subtype and EBER presence. There was a striking similarity in FHD subtypes of each family and 3/11 (27%) of the cases were EBER positive. In conclusion, EBV EBERs are only infrequently found in FHD and other factors including viruses different from EBV should be further investigated in FHD.

Female↗
PubMed1994

Immunoblotting detection of so-called 'antikeratin antibodies': a new assay for the diagnosis of rheumatoid arthritis.

OBJECTIVES: To assess the diagnostic value for rheumatoid arthritis (RA), of an immunoblotting assay based on the rat oesophagus epithelium antigens recognised by the so-called 'antikeratin antibodies' ('AKA'), antigens that have been identified as three non-cytokeratin proteins (referred to as A, B and C proteins). METHODS: After polyacrylamide gel electrophoresis in non-denaturing conditions and electrotransfer of an epithelial extract, the immunoreactivities to the A, B and C proteins of a series of serum samples from 88 patients with RA and 100 patients with non-rheumatoid rheumatic diseases, were semiquantitatively evaluated. RESULTS: A total of 81.8% of RA serum samples recognised the three proteins, while 91% of non-RA serum samples only weakly recognised the A and B proteins but not the C protein. Only in the group of RA patients, were the titres of the antibodies to the A, B and C proteins found to be significantly correlated with each other and with the titres of 'AKA' detected by the standard indirect immunofluorescence (IIF) method. For a diagnostic specificity of 99%, the diagnostic sensitivities of the detection of the A and B proteins were 50% and 43.2%, respectively, when those of the detection of 'AKA' by IIF and of IgM-rheumatoid factor by enzyme-linked immunosorbent assay were 42% and 54%, respectively. In contrast, at a same specificity of 99%, the diagnostic sensitivity of the detection of the C protein was significantly higher with a value of 70.5%. CONCLUSION: This immunoblotting assay which is the first immunochemical method proposed for the detection of 'AKA, should be validated on larger series of patients but can already be considered as a very powerful test for the serological diagnosis of RA.

Arthritis, Rheumatoid↗
PubMed1994

Long-term follow-up of monoclonal gammopathy of undetermined significance in transplant patients.

We report the long-term follow-up of 5 patients (4 kidney, 1 heart recipients) having a pretransplant monoclonal gammopathy of undetermined significance (MGUS). The follow-up of MGUS before transplantation was 41.2 +/- 40.7 months (range 2-108). The monoclonal component isotype was IgG-kappa in 3 cases and IgA-lambda in 2. The pretransplant level of the monoclonal component was 11.1 +/- 4.8 g/l (range 4-15.6). The transplant recipients who had MGUS were older than our other transplant patients. All but one of them received ciclosporine A. They did not experience more rejection or infectious complications than the others. Their posttransplant follow-up ranged from 3 to 9 years. The monoclonal component level remained stable in 2 patients but increased in 3 (33-225%). This was not correlated with bone marrow plasmocytosis. Two patients developed smoldering myeloma indicated by bone marrow immunochemistry studies which showed monomorph monoclonal plasma cells; nevertheless, they did not have cytopenia or bone lytic lesions. This percentage is higher than in the Kyle study but we cannot assume that it is due to ciclosporine A since our study sample is too small. In conclusion, MGUS is not a contraindication to organ transplantation.

Contraindications↗
PubMed1993

Association of tumor necrosis factor (TNF) and class II major histocompatibility complex alleles with the secretion of TNF-alpha and TNF-beta by human mononuclear cells: a possible link to insulin-dependent diabetes mellitus.

We have investigated the correlation between different tumor necrosis factor (TNF) and class II major histocompatibility complex alleles in the lipopolysaccharide- or phytohemagglutinin-induced secretion of TNF-alpha and TNF-beta by human monocytes and peripheral blood mononuclear cells in 87 unrelated Danish male individuals. Significant differences in TNF-alpha secretory capacity between TNF NcoI restriction fragment length polymorphisms, TNFa and TNFc microsatellite alleles and DR alleles were identified. No correlation with TNF-beta secretory capacity was found for any of the markers studied. TNF genotyping allowed us to define four extended HLA haplotypes which correlate with TNF-alpha secretory capacity. Two of these are DR4 positive: DQw8, DR4, TNFB*1, TNFa6, B44, A2 and DQw8, DR4, TNFB*2, TNFa2, B15, A2. Individuals carrying the TNFB*2, TNFa2 haplotype had a higher TNF-alpha secretory capacity than those carrying the TNFB*1, TNFa6 haplotype. In a group of DR3/DR4 heterozygous patients with insulin-dependent diabetes mellitus (IDDM), the frequency of the TNFa2 allele was higher than in HLA-DR matched controls, whereas the TNFa6 allele was more frequent in control individuals. In the DR3/DR4 heterozygous diabetic group 12/26 had the alleles combination DQw8, DR4 (Dw4), C4A3, TNFB*2, TNFa2, B15, whereas only 1/18 controls had this haplotype. This diabetogenic haplotype is identical to the DR4 haplotype which correlates with a higher TNF-alpha response. These observations suggest a direct role for the TNF locus in the pathogenesis of IDDM.

Adolescent↗
PubMed1992

[Study of CD45 isoforms on T CD8 lymphocytes, in the peripheral blood and the graft in patients after kidney transplantation].

We report characterization of CD45 isoforms expressed by CD8+ lymphocytes in peripheral blood and in the graft of 40 kidney transplanted patients who underwent kidney biopsy on the basis of clinical signs suggesting rejection. Standard histological examination of the biopsy fragments and three-color cytofluorimetric analysis of lymphocytes extracted from the same fragments by mechanical and enzymatic treatment were performed simultaneously and compared to the peripheral blood lymphocytes. In 14/40 biopsies where lymphocyte extraction succeeded, the predominant subset was CD8 (CD4/CD8 mean ratio was 0.53). Almost all CD8+ cells were activated: among these CD8+ cells, 55 percent were HLA-DR+, and 68 percent CD45RO+, i.e. of a memory cell type with cytotoxic activity. This situation resembles the in vitro observation made during mitogenic stimulation of lymphocytes by phytohemagglutinin, OKT3 or CML ("culture mixte lymphocytaire"). Beside their evident interest for the diagnosis, these data could be useful for our understanding of the physiopathology of the rejection crisis.

Biopsy, Needle↗
PubMed1992

Apparently non-expressed alleles of factor B (BF) code for hypomorphic proteins.

In three families with an apparent non-expressed factor B (BF) allele (BF*Q0), advanced methods of isoelectric focusing for the determination of BF F subtypes revealed different hypomorphic BF products (BF QL) with functional hemolytic activity expressed by the assumed BF*Q0 allele. A Taq I and a Msp I restriction fragment length polymorphism as well as the Ba fragment of the expression products showed banding patterns for the BF*QL alleles corresponding to BF S types, whereas an altered Bb fragment was seen in two BF QL products. In one family an intragenic recombination site within the Bb part of the BF gene was assumed. Investigations of factor B and its conversion fragments, as demonstrated by the used methods, allow to complement molecular genetic investigations of BF*Q0 alleles in heterozygous genotypes on a protein level. We conclude that apparently non-expressed alleles of factor B code for hypomorphic but functionally active proteins.

Alleles↗