Plasma fibronectin in various hemopathic diseases.

Plasma fibronectin was determined by laser nephelometric immunoassay in two populations: (a) healthy subjects separated into three age groups (16-29 yr, 30-50 yr and over 50 yr) and, (b) patients with various hemopathic diseases without any infection or any therapy. Results showed that fibronectin levels in a healthy population were strongly influenced by age. An increase of human plasma fibronectin was shown to occur with age. Results in hemopathic patients were expressed in terms of percentage of mean deviations as compared to normal mean values for the corresponding age range. We found that plasma fibronectin was significantly decreased in acute myeloblastic leukemia, especially in transfused patients, polycythemia vera, osteomyelofibrosis. Waldenström disease, benign dysproteinemia, refractory anemia and stage IV non-Hodgkin malignant lymphoma. Plasma fibronectin-decreased levels appear to be of prognostic value in the evolution of malignant hemopathic diseases.

[Variations of the concentrations of certain glycoproteins in maternal serum, fetal serum and amniotic fluid during pregnancy (author's transl)]. / Variations des concentrations de certaines glycoprotéines au niveau du sang maternel, foetal et du liquide amniotique lors de la grossesse

The authors investigated systematically the variations during normal pregnancies of the concentrations of alpha-1-antitrypsin, orosomucoid, transferrin and alpha-fetoprotein simultaneously in maternal serum, fetal serum and amniotic fluid. The role of certain factors such as the gestational age birth weight, placental weight and pairty were studied with regard to variations in the concentrations of each of these proteins. This research permitted the definition during pregnancy of the normal concentrations for these four proteins and allowed us to learn more about protein exchanges between fetal blood, maternal blood and amniotic fluid. There exists a difference between the concentrations of alpha-1-antitrypsin and of orosomucoid found for primigravidae and for multigravidae. The role of these glycoproteins in preventing the mother from rejecting the fetus (insofar as the fetus may be considered as an allograft) is discussed.

Simultaneous determination of C1q and C3 levels in human serum by electroimmunodiffusion on agarose.

An electroimmunodiffusion method for the simultaneous determination of C1q and C3 levels in human serum is proposed. The reproducibility is good, and an excellent correlation is observed between electroimmunodiffusion and radial immunodiffusion. This simple, fast, and accurate method is suitable for clinical investigation.

Inhibition of induced lymphocyte proliferation by lipid and protein components of the syncytiotrophoblast plasma membrane.

PROBLEM: The aim of this work was to define the respective responsibilities of the lipid and protein components of syncytiotrophoblast plasma membranes on the inhibition of lymphocyte proliferation induced in vitro. METHOD: A fractionation method using octyl-beta-D-glucopyranoside enabled lipoprotein, lipid, and protein fractions to be isolated from the membrane. RESULTS: The lipid fraction was shown nonspecifically to inhibit lymphocyte proliferation, to a lower extent compared with the native membrane. Alternatively, the protein fraction used as a proteoliposome contained the totality of the cytostatic effect of the native fraction. CONCLUSION: These results are discussed generally in the context of the immunoregulatory role of membrane lipids and proteins and in relation to the local properties of syncytiotrophoblast plasma membrane components in fetal graft tolerance.

Adhesive properties of choriocarcinoma cells toward lymphocytes activated or not by interleukin-2.

Choriocarcinoma cells (CC) in vitro are resistant to NK lysis but sensitive to lysis by blood or decidual effectors activated by interleukin-2 (IL-2). Because lytic activity requires a step of adhesion, the adhesive properties of the choriocarcinoma cells BeWo, JEG-3, and JAR were examined functionally toward peripheral blood lymphocytes. The adhesion of lymphocytes to choriocarcinoma cells was very low and did not increase after stimulating lymphocytes with IL-2. As demonstrated by cytofluorimetry analysis, choriocarcinoma cells and cytotrophoblast cells prepared from term placenta expressed intercellular adhesion molecule-1 (ICAM-1), whereas only CC expressed CD56. Tumor necrosis factor-alpha or interferon-gamma increased the expression of ICAM-1 on choriocarcinoma cells without modifying the adhesion of lymphocytes to choriocarcinoma cells. These results suggest that resistance of choriocarcinoma cells to lysis by cytotoxic effectors could partially be attributed to the low level of lymphocyte adhesion to these cells.