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Biomedical subjects

J Jouquan

Publications and source records attributed to J Jouquan.

At least 19 recordsLinked to original sources
PubMed1997

Interaction between certain major histocompatibility complex class II and T-cell receptor V beta alleles promotes the antibody production to extractable nuclear antigen-related peptides.

Our objective was to study the interaction between major histocompatibility complex (MHC) class II and T-cell receptor (TCR) alleles in the recognition of extractable nuclear antigen-derived peptides in 32 patients with systemic lupus erythematosus and 173 of their family members. MHC genes were analyzed using sequence specific oligonucleotides, and TCR beta-chain gene polymorphism using restriction fragment-length polymorphism. One dominant peptide (as defined by enzyme-linked immunosorbent assay autoantibody reactivity) was identified in each antigen studied: peptide 1-20 in Sm-D, peptide 35-58 in U1-RNP-A, and peptide 304-324 in the Ro/SSA 60 Kd protein. None of the MHC class II and TCR beta haplotypes was directly associated with any of the autoantibodies. Twenty-six subjects had antibodies to the peptide Sm-D1-20; nine of them were DRB1*0101/DQB1*0501. Among subjects with this haplotype, the number of responders was higher (p < 0.028, p corrected, pc = 0.336) in those with the 2-25-9 TCR beta haplotype than in the remainder. Conversely, the number of DRB1*04/DQB1*0302 responders was lower (p < 0.030, pc = 0.360) among subjects with the 23-20-9 TCR beta haplotype than in those without. The odds ratios (OR) were 4.23 and 0.21, respectively. Of the 54 subjects positive for anti-U1-RNP-A 35-38, 13 were DRB1*0101/DQB1*0501 and eight DRB1*04/DQB1*0302. The percentage of responders was higher (p < 0.041, pc = 0.492, OR = 3.48) in the former group of subjects with the 2-25-9 TCR beta haplotype, and lower (p < 0.02, pc = 0.024, OR = 0.09) in the latter with the 23-20-9 TCR beta haplotype. Three of the 12 anti Ro/SSA 60Kd 304-324-positive subjects were DRB1*0101/DQB1*0501. All had the 2-25-9 TCR beta haplotype (p < 0.046, pc = 0.552, OR = 6.29) and none the 23-20-9 (p < 0.031, pc = 0.372, OR = 0.10). The same combinations of genes were associated with high/low response toward the three peptides. These data provide evidence for an interplay of the MHC class II and TCR beta alleles in the control of specific autoantibody response to well-defined nuclear Ag peptides.

Adolescent↗
PubMed1997

[Knowledge and beliefs of 4th-year medical students concerning professional practices in general medicine. Results of a survey conducted at the School of Medicine of Brest].

As part of preparations for the first seminar in general practice, organized for medical students in their forth year at the Brest faculty of medicine, students were asked to fill in a questionnaire concerning their beliefs and knowledge concerning general-practice medicine. Fifty-two students, or 89.6% of the class, completed the questionnaires. The results showed that despite the lack of formal contacts with this type of practice during their studies, the students had a good idea of what general-practice medicine is and of the role of the general practitioner in our health-care system. However, this study has illustrated the difficulties students experience in defining their future professional direction, since they receive no information during their training on the different options in medical practice.

Adult↗
PubMed1996

Interplay of four idiotypes and interaction with autoantibodies in lupus patients, their relatives and their spouses.

Our aim was to investigate links between systemic lupus erythematosus (SLE)-associated autoantibodies, idiotypes (Id) and genetic predisposition to their development. We studied four public Ids (16/6, WRI 176 beta, RT72 and RT84), identified the Km and Gm phenotypes and sought six selected autoantibodies in 32 SLE patients, 174 of their relatives and 15 spouses. Though anti-double-stranded DNA antibody was uncommon in the relatives (9%), the range of antinuclear reactivities was as broad in the relatives as in the probands. Antibodies to the synthetic peptide U1-RNP-A 35-38 were found in 56% of the patients, 28% of their relatives and 20% of the spouses, whereas antibodies to the Golgi apparatus was present in 7% of the patients, 26% of their relatives and 33% of the spouses. However, most of these family members were unaffected. RT84 Id was positively associated with antibodies to Sm-D peptide 1-20 and to Ro/SSA 60 kD peptide 304-324, but negatively associated with anti-dsDNA activity. The median of age was significantly lower in the RT84 Id-positive than in the RT84 Id-negative individuals. These data suggest that genetic as well as environmental factors are involved in the aetiology of SLE. In addition, RT84-carrying immunoglobulins (Ab2) might be directed to one of many cross-reactive Ids of dsDNA-binding antibodies (Ab1), perhaps down-regulating their production.

Adolescent↗
PubMed1995

The relationship of anti-endothelial cell antibodies to anti-phospholipid antibodies in patients with giant cell arteritis and/or polymyalgia rheumatica.

Sera from patients with giant cell arteritis and/or polymyalgia rheumatica were tested for the presence of IgG, IgM and IgA antibody to endothelial cells (AEC), cardiolipin (ACL) and phosphatidylethanolamine (APE) using enzyme-linked immunosorbent assays. There were strong correlations between ACL and APE, but also between AEC and ACL IgM (p < 0.02) and between AEC and APE IgA (p < 0.003). Inhibition of AEC binding was achieved by absorption onto EC, but ACL and APE binding was also significantly reduced. In contrast, the binding of AEC antibody could not be inhibited by incubation with CL. Our data suggest that AEC constitute a heterogeneous population of autoantibodies.

Aged↗
PubMed1995

Some nutritional parameters in patients with rheumatoid arthritis.

Its was our aim to appreciate the respective influence of age, sex, duration of disease, inflammatory status and treatment on protein markers in patients with rheumatoid arthritis (RA). Serum albumin (SA), thyroxin-binding prealbumin (TBPA), transferrin and retinol-binding protein (RBP) were determined in 155 RA patients. Since the cut off, levels of these proteins are highly dependent on sex and age, several groups of sex- and age-matched normal controls were evaluated. The levels of SA (p < 0.03) and RBP (p < 0.002) were reduced in the women under 45 years of age. SA and RBP reached a nadir following one year of evolution. There were inverse correlations between SA and Lee's index (p < 0.01) and TBPA and Lee's (p < 0.05) and Ritchie's index (p < 0.01). Sa correlated inversely with the inflammatory status. The complex challenge of nutritional evaluation in RA patients is thus impossible to adequately portray and results should be interpreted with caution.

Adolescent↗
PubMed1993

[Immunogenetics of systemic lupus: adequacy between HLA molecules class II and the germinal genes of antigen receptor of T-lymphocytes favours the production of various antibodies].

The study of 30 patients with systemic lupus and of 153 relatives failed to show any differences in HLA and TCR beta haplotype frequencies between patients and relatives. A significant interaction between TCR V beta and HLA-DR/DQ genes in the response to the peptide U1-RNP A 35-58 was demonstrated.

Antibody Formation↗
PubMed1993

Dopamine B hydroxylase deficiency responsible for severe dysautonomic orthostatic hypotension in an elderly patient.

We report the case of an elderly woman with severe dysautonomic orthostatic hypotension in whom a deficit in dopamine B hydroxylase has been established. In the literature, such a deficit has been described in six young adults with long standing symptoms of postural hypotension. This enzyme catalyses the conversion of dopamine to noradrenaline. In our elderly patient, noradrenaline and adrenaline were undetectable in the plasma, but plasma dopamine was detectable. Treatment with the synthetic amino acid, DL-threo-dihydroxyphenylserine, which is converted to noradrenaline by dopa-decarboxylase, resulted in a significant increase in blood pressure. The mechanism of this acquired deficit is not elucidated.

Aged↗
PubMed1992

Anti-neutrophil cytoplasm antibodies in patients with giant cell arteritis and/or polymyalgia rheumatica.

Anti-neutrophil cytoplasm antibodies (ANCA) were detected at low titers by indirect immunofluorescence in 1 out of 13 patients with giant cell arteritis (GCA) alone, 7 out of 30 with polymyalgia rheumatica (PMR) alone and 4 out of 15 with GCA plus PMR (8, 23 and 27%, respectively). Anti-myeloperoxidase antibodies were also demonstrated by an enzyme-linked immunosorbent assay in 4 patients with GCA alone (31%), 13 with PRM alone (42%) and 5 with GCA plus PRM (33%). The C-reactive protein response was significantly higher (p < 0.05) in ANCA-positive than in ANCA-negative patients.

Aged↗
PubMed1991

Nonorgan-specific autoantibodies in individuals infected with type 1 human immunodeficiency virus.

Fifty-six human immunodeficiency virus-1-positive asymptomatic carriers were tested for the presence of a variety of nonorgan-specific autoantibodies. Antinuclear antibodies were detected in 34 sera, of which 27 were directed to the mitotic spindle apparatus and all were of the IgG isotype. Anti-Golgi complex, anti-centriole, and anti-vimentin antibodies were also present in 20.4, and 4 sera, respectively. Ten patients had less than 500 CD4-carrying T lymphocytes per cubic millimeter. Nine of them had more than one autoantibody. No correlation could be demonstrated between the number of autoantibodies and the level of serum immunoglobulins.

Adult↗
PubMed1991

IgA-containing immune complexes in the circulation of patients with primary Sjögren's syndrome.

IgA-, IgM- and IgG-containing immune complexes (CIC) were detected in 48, 19 and 12% of 52 patients with primary Sjögren's syndrome (SS), in 36, 38 and 56% of 45 patients with rheumatoid arthritis, and in 8, 5 and 3% of 40 normal controls. A high proportion of primary SS patients also had considerable amounts of serum IgA and elevated levels of IgA with rheumatoid factor (RF) activity. IgA-CIC and IgA-RF were more frequent (P less than 0.03 and less than 0.001) in the 27 primary SS patients with, than in the 25 without extraglandular manifestations. IgA-CIC could play a role in mediating the tissue injury associated with primary SS.

Adult↗
PubMed1990

The relationship between CD5-expressing B lymphocytes and serologic abnormalities in rheumatoid arthritis patients and their relatives.

The influence of genetic factors on the expression of CD5+ B lymphocytes and their relationship to a broad spectrum of autoantibodies was investigated in a study of 12 patients with rheumatoid arthritis (RA) and 52 of their healthy first-degree relatives. The proportion of CD5+ B cells was significantly higher in RA patients (mean +/- SEM 23.9 +/- 2.7%) compared with that in their relatives (18.3 +/- 1.1%, P less than 0.05) and compared with that in a group of healthy control subjects (16.1 +/- 1.8%; P less than 0.05). Much more striking, however, were the high levels of CD5+ B cells found in the patients and their relatives in 5 of the families studied. Increases in total immunoglobulin levels and autoantibody levels were frequently observed in RA patients (approximately 20-40%) and their relatives (approximately 10-20%). Furthermore, a statistically significant correlation (P less than 0.01) between IgM rheumatoid factor and the percentage of B lymphocytes expressing CD5 was observed.

Adult↗
PubMed1990

Raynaud's phenomenon in primary Sjögren's syndrome.

Forty-five consecutive primary Sjögren's syndrome (SS) patients were divided into two subgroups according to the presence (n = 30) of Raynaud's phenomenon (RP). Non-erosive arthritis was significantly more frequent in the patients with RP than in those without. RP was not associated with HLA-DR4 in primary SS patients.

Adult↗
PubMed1990

The antibody repertoire of early human B cells. I. High frequency of autoreactivity and polyreactivity.

Cord blood and fetal liver B cells were immortalized using Epstein-Barr virus, and IgM antibodies from the resulting lines and clones were examined for their binding to a variety of auto-antigens and micro-organisms by ELISA and fluorescence assays. Auto-antigens tested included Fc of IgG, ssDNA and dsDNA, cardiolipin, histones 1-4, collagens type I and II, thyroglobulin, cytoskeletal components, and a tissue section screen. Of 71 cell lines tested, all but 19 showed some autoreactivity. All 32 fetal liver lines reacted to some self-antigens. In cord blood clones, 16 out of 26 bound to auto-antigens. Many of the clones reacted with more than one auto-antigen and were 'polyreactive'. Some of the cord blood clones bound to extracts of micro-organisms, showing specificity for both endogenous and exogenous antigens. The high frequency of CD5+ B cells in the cord blood (greater than 50%) and fetal liver (greater than 70%) argues for many of these clones being derived from this subset. Therefore, our data support the concept that many 'early' B cells produce polyreactive IgM which can bind to a variety of different auto-antigens and micro-organisms. These IgM antibodies are similar to those described by others as 'natural antibodies'.

Antibody Specificity↗