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Biomedical subjects

B Genetet

Publications and source records attributed to B Genetet.

At least 109 records · Page 6Linked to original sources
PubMed1982

[Immunological changes following heart surgery under extracorporeal circulation (author's transl)].

Post-operative immunological changes were studied in 40 patients undergoing heart surgery. Tty-five patients were operated upon under extracorporeal circulation (ECC), and 15 without ECC. Immunological investigations were performed before, immediately after the operation and again 7 days later. The post-operative changes recorded were early decrease in IgG and IgM followed by a rise in IgM, transient lymphocytopenia affecting mainly T lymphocytes and delayed increase in complement (CH50, C2, C3). These changes were comparable in both groups of patients and therefore seemed to relate to the operation itself rather than to the ECC. It may be concluded that ECC does not appear to increase the risk of post-operative infection by depressing immune defence mechanisms.

Adolescent↗
PubMed1982

HLA profiles in multiple sclerosis suggest two forms of disease and the existence of protective haplotypes.

261 multiple sclerosis (MS) patients were HLA-A and -B typed and 94 were HLA-D typed. The results were compared to those of controls typed for HLA-A; HLA-B (356) and HLA-D (113). We confirm and extend earlier findings (Oger et al. 1980b) that some phenotypes could modulate the expression of the MS susceptibility gene linked to B7-DR2: DR3 was found together with DR2 in 12/94 MS and only 3/113 controls and could be marker for an "augmentor" gene. In contrast, B35 and DR1 as well as B12 and DR7 could be markers of protector genes. We compared typing results of patients subgrouped on clinical features. 61 patients with progressive evolution showed increased A1, A1-B8, B8-DR3 and A1-B8-DR3 when compared to 200 patients with remitting evolution. When compared to controls both groups showed increased B7 but only the remitting group showed increased DR2. 71 patients with "benign MS" showed increased B7-DR2 and A3-B7-DR2. 54 patients with "severe disease" showed increased DR3 and A1-B8-DR3 when compared to controls. Both groups showed increased B7 (49.2% and 44.4% versus 25.5% for controls). 120 patients treated greater than 5 years with azathioprine were divided into "no progression" and "progression" while treated. Both groups showed increased B7 when compared to controls. DR2 was increased only in the "no progression" group. B8-DR3 and A1-B8-DR3 were found increased in the "progression" group only. We conclude that two forms of MS exist with different HLA profiles.

Adolescent↗
PubMed1982

A monoclonal antibody to the HLA-A3 alloantigen.

Monoclonal antibody production recognizing the HLA-A3 antigen is described. The XI-23 antibody reacted with all of the 89 cell suspensions carrying the HLA-A3 antigen (100% cytotoxicity) among a total of 191 suspensions tested. No extra-reactivity or cross-reactivity was observed, particularly with that of HLA-A11. This antibody can thus be considered as a good HLA-typing reagent.

Animals↗
PubMed1982

The role of human spleen interferon on natural killer activity of peripheral blood lymphocytes enriched in large granular lymphocytes.

The elimination of monocytes as well as B- and T-lymphocytes by forming rosettes with high affinity for sheep red blood cells yielded an enriched population of both natural killer (NK) activity (cytotoxicity: 65.4 +/- 9.9% with an E/T ratio of 12:1, P less than 0.005) and large granular lymphocytes (LGL: 76 +/- 13%) compared to the untreated lymphocyte population where NK activity is 35.7 +/- 17.3% (E/T 12:1) and the percentage of LGL of 26 +/- 6%. We studied the action of type I interferon (IFN) obtained from human spleens, on NK activity of 9 peripheral blood lymphocyte populations and 9 enriched in LGL. NK activity of the total lymphocyte population is significantly increased (P less than or equal to 0.05) in 6 out of 9 cases after treatment by interferon. Cell populations enriched in LGL showed increased NK activity in only one case after treatment by interferon, but no increased activity was found in the other cases. These results are compatible with the notion of cellular cooperation in increased NK activity by interferon.

B-Lymphocytes↗
PubMed1982

Allogeneic responses in vitro induced by fetomaternal alloimmunization.

The present study was undertaken in order to determine what type(s) of pregnancy-induced allogeneic reaction could alter MLC (mixed lymphocyte culture) reactivity in routine HLA-D typing of lymphocytes in multiparous women (MW) possessing antibodies against paternal HLA-DR antigens. Unresponsiveness to homozygous typing cells (HTC) representing a paternal and probably fetal HLA-DR determinant was frequently observed. Kinetics experiments ruled out an early secondary proliferative response to HTC representing the paternal HLA-D determinant, which would be missed in a classical long-term mixed lymphocyte culture. Direct cytotoxicity against paternal or panel target cells was not always associated with inhibition of proliferative response to the same stimulator cell. Specific anti-HLA-DR blocking activity (antibodies?) in the supernates of restimulation reactions of lymphocytes from MW could be responsible for this inhibitory effect. Moreover, the study points to the existence of suppressor cells in the immunized MW acting independently of specific restimulation. The in vitro suppression appeared to be selective, restricted to cells sharing HLA-D linked structures with the suppressor cells, and suggests that auto-regulator mechanisms could be induced in pregnancy in order to modulate antibody production.

Antibodies↗
PubMed1982

Changes in cAMP metabolism during phagocytosis of S. aureus by human monocytes.

Involvement of cyclic adenosine 3',5'-mono-phosphate (cAMP) in the phagocytosis of staphylococci by human monocytes was demonstrated by assay of adenylate cyclase and cAMP phosphodiesterase (PDE). Monocyte adenylate cyclase and PDE activities were assayed on cell homogenates prepared from monocytes isolated by plate adherence. Phagocytosis of staphylococci was associated with diminished adenylate cyclase activity, which reached a minimum after 10 min of incubation (p less than 0.05), and an increase in PDE activity (p less than 0.005). Transmission electron microscopy provided evidence that these changes coincide with peak phagocytic activity occurring between 10 and 20 min after the start of phagocytosis but could not be assigned to a particular stage in the phagocytic process.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1981

HLA-A, -B, and -DR specificities on human monocytes.

Monocyte-enriched cell suspensions obtained by a plate adherence method from 57 blood donors were typed by microcytotoxicity for HLA-A, -B and -DR determinants. Parallel assays were performed with autologous unfractionated lymphocytes for HLA-A and -B determinants and with autologous B-lymphocytes for HLA-DR determinants. Correlation coefficients (r values) were calculated for nine HLA-A specificities (r greater than 0.79), 16 HLA-B specificities (r greater than 0.56) and seven HLA-DR specificities (r greater than 0.81). For certain HLA-A and -B specificities detection was less readily achieved on monocytes than on autologous lymphocytes. Extra reactions were observed in some instances. With sera defining HLA-DR specificities, monocytes and B-cells showed reactivity of almost identical strength and reliability.

Antigens, Surface↗
PubMed1981

Filterability and bank blood conservation media.

A study was made of storage lesions of packed red cells stored in different preservative media: CPD, CPD-adenine, CPD-SAG, and CPD-pentoxifylline. The following chemical and physical parameters were studied: filterability, viscosity, ATP, 2-3,DPG pH, osmotic fragility, scanning electron microscopy pattern, blood gas levels. Tests were performed on days 0, 2, 4, 8, 16 and 24. The number and intensity of storage lesions in vitro give an indication of changes in oxygen-delivery capacity and flow characteristics of erythrocytes over a period of storage at 4 degrees C in different preservative media. CPD was found to maintain pertinent RBC properties up to Day 15. Adding adenine made little difference, whereas adding SAG gave better results. Pentoxifylline did not show appreciable effects in the initial concentrations used, which were close to those employed in medical practice. A preservative mixture ensuring maintenance of normal blood values during storage at 4 degrees C has yet to be found. Continued study of pentoxifylline should be conducted using higher concentrations of this additive.

Adult↗
PubMed1980

[Graves' disease. Predominance of the DRw3 antigen (author's transl)].

HLA-A, B, C antigens were studied in 86 white european patients with Graves' disease, using a lymphocyte toxicity microtechnique and the results were compared with those obtained in 356 healthy subjects. HLA-D (DR) antigens were studied by the same technique after prolonged incubation and the results were compared with those of 100 healthy controls. The incidence of DRw3 was 51.16% in the patients as against 20% in controls, the difference being highly significant (pc--PC less than 0.0003) - corrected p = p multiplied by the number of antigens tested. There was also a significant (pc less than 0.001) increase in HLA-BB: 44.19% against 22.47%, and in HLA-A1: 40.7% against 28.93% (pc less than 0.03). Conversely, there was a decrease in the incidence of HLA-B12: 12.79% against 31.74% (pc less than 0.01). B8 was found to be associated with DRw3 in 37 of the 86 patients, but in only 13 of the 100 controls (p less than 0.00003). There was no correlation between the HLA antigens and the clinical features of the disease (presence or absence of goitre and exophthalmos, severity of clinical or biological symptoms). These results are in agreement with those of other studies reporting an increase in HLA-B8. The increase in HLA-A1 is probably due to an accentuation of the unbalanced linkage with B8. The major finding was the predominance of the DRw3 antigen, also found by other authors working with a mixed lymphocyte culture. It seems therefore possible that the putative Graves' disease susceptibility antigen is present on the sixth chromosome, near to HLA-D (DR).

Adolescent↗
PubMed1980

Occurrence and specificity of anti-B lymphocyte antibodies in renal allograft recipients.

Anti-HLA-A,B and anti-B lymphocyte antibodies were screened as part of a prospective alloimmunity monitoring study in 29 renal allograft recipients using a standard microlymphocytotoxicity test. Warm-reactive and/or cold-reactive lymphocytotoxins were directed against a panel of B lymphocytes, the donor's B lymphocytes, and the recipient's own B lymphocytes. A small proportion of patients had pretransplant antibodies, whereas about one-half of the patients had post-transplant antibodies. One-year allograft survival rates were lower among the patients with warm- and cold-reactive sera than among those with nonreactive sera or pure B cold-reactive sera. The sera of 20 patients were tested against donor B lymphocytes. The presence of donor-specific antibodies correlated closely enough with graft loss to be of predictive value. Autoantibodies appeared to have an enhancing effect in this study.

Antibody Specificity↗