Biomedical subjects
Publications and source records attributed to P Gausset.
In this condensed review, we present some of the most important mechanisms which induce allo-immunisation among patients who receive blood transfusions. The understanding of these mechanisms implies simple blood transfusion rules which guarantee the recipient's safety.
A simple one-step ELISA to detect anti-CMV antibodies was developed. The test was based on the inhibition principle, and used anti-CMV coated microtitre plates, CMV nuclear antigen and anti-CMV Fab'-HRP conjugate; total assay time was 1.5 h. The use of Fab'-HRP conjugates improved discrimination between positive and negative sera as compared with IgG-HRP conjugates. In an in-house clinical study, the one-step ELISA showed a 98.4% correlation with the latex agglutination test. The test could be demonstrated to be suitable for both serum and citrate- or EDTA-plasma specimens; heparin-plasma gave somewhat higher absorbance values. In an external clinical validation, the one-step ELISA showed a 99.5% correlation with the latex agglutination test, and was found to be highly suitable for screening of blood donor specimens in a blood bank setting.
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Human tonsil lymphocytes have been separated into three subpopulations of cells: purified B cells and two subsets of purified T cells (F1 and F2). B cells were obtained by rosetting with neuraminidase treated SRBC. F1 and F2 were separated by filtration on a nylon wool column using different speeds of elution. Purified B cells contained less than 5% T cells, the T cells preparations contained less than 5% B cells for F1 and 10 to 15% for F2, respectively. A significant contamination in cells not identified by any B or T marker was observed in purified B cells and in F1. Adherent cells enhanced the response of each lymphochte population to PHA and Con A. This explained the paradoxically low responsiveness of the purified T cells. Purified B cells did not respond to these mitogens in different culture conditions. However, a small B cell response was observed when they were cultured in the presence of mitomycin-treated T cells. Striking was the enhancing effect of B cells on the T cell response to PHA and Con A. This enhancing effect was observed even when B cells were treated with mitomycin or depleted in adherent cells. The comparison of the F1 and F2 response suggested that they contained distinct types of T cells.
A significant and constant increase in DNA synthesis was observed in human lymphocytes cultured in the presence of purified anti-immunoglobulin antibodies specific for human IgG, IgA, and IgM. This has been found in cultures of lymphocytes isolated from blood, tonsils, spleen, and lymph nodes. The optimal culture conditions for blood and tonsil lymphocytes were determined. As a rule 6-day cultures containing 2 x 10(6) cells/ml and 100 mug/ml of antibody yielded the highest 3H-thymidine uptake. Purified T cell cultures could not be stimulated, whereas a low response could be observed in most of the purified B cell cultures. Optimal culture conditions were the same for the B and total tonsil lymphocytes. However, when the purified B cells were totally depleted of T cells, no response was observed. A T and B cell synergy has been demonstrated by supplementing B cell cultures with purified T cells, whether treated or not with mitomycin. These experiments indicated a permissive and potentiating effect of T cells on the B cell response. Cultures containing mitomycin-treated B cells and purified T cells (mB + T) could be stimulated by a-Ig, thus indicating a T cell proliferation. In keeping with this finding was the observation of an increased response of total lymphocytes supplemented with T cells but not with B cells. Adherent cells are necessary for an optimal response to a-Ig; they enhanced the B cell proliferation observed in (Tm + B) cultures and suppressed the response of T cells in (T + Bm) cultures.
Five patients with no detectable serum IgA (less than 20 mug/ml) and one patient with low serum IgA were compared to normal subjects. The number of circulating E-RFC was normal as was the lymphocyte DNA synthesis induced by PHA, Con A, and streptokinase-streptodornase. The patients had normal numbers of IgA-bearing lymphocytes and normal or increased numbers of B cells. Purified anti-immunoglobulin antibodies specific for IgG, IgA and IgM induced a normal lymphocyte DNA synthesis as did PWM. The patients' lymphocytes were able in vitro to transform into actively secreting IgA plasmocytes. This transformation was determined by counting the IgA and immunoglobulin-containing cells and then measuring the IgA and IgG secretion in the cultures. In some patients PWM was selectively suppressive in IgA B-cell transformation into IgA secreting cells; in the other patients PWM had no effect on the IgA B-cell differentiation. PWM enhanced the IgG secretion in the patients' cultures as well as IgA and IgG secretion in the normal controls.
Peripheral blood lymphocytes (PBL) from old subjects were less responsive to PHA than those from young controls, in both groups the PBL content of macrophages, T and B cells were comparable. Macrophages were identified as peroxydase containing cells, rosette formation with sheep red blood cell was used as a T cell marker and immunoglobulin bearing lymphocytes were considered to be B cells. PBL were separated in two subpopulations of purified T cells (F1 and F2) differing in their responsiveness to PHA and in their ability to cooperate with B cells. Purified B cells had a synergistic effect on the F1 response to PHA whereas they were often suppressive for the corresponding F2 response. Peroxydase containing cells enhanced the response of unfractionated total PBL and of purified T cells in the young subjects. The depressed response of the old age group could be related mainly to a suppressive effect of monocytes and a decreased circulating pool of F1 T cells.
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A case of auto-immune haemolytic anaemia during pregnancy is described. The different tests carried out on the patient make the diagnosis of idiopathie auto-immune haemolytic anaemic haemolytic anaemia in this case. Several theories have been reviewed in order to try and explain the possible role of pregnancy in the appearance of worsening of this kind of anaemia. The theory most likely to be true is that it is a slowly evolving process of auto-immunisation in which the haemolytic effect was accelerated by the pregnancy and showed itself clinically because of the haemodynamic factors occurring at the placental site.
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