Biomedical subjects
Publications and source records attributed to J Wybran.
Determination of fetal red blood cell Kell antigen is possible on fetal red blood cells obtained at 10 weeks of gestation by chorionic biopsy and may contribute to the management of severe Kell-hemolytic disease.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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In vitro effects of three immunosuppressive drugs, cyclosporin, methylprednisolone, and 6-mercaptopurine (the active moiety of azathioprine), have been assessed by various proliferative assays including mixed lymphocyte reaction (MLR), concanavalin A (Con A), OKT3 monoclonal antibody (MoAb), phorbol myristate acetate (PMA), and A23187 ionophore-induced mitogenesis. The influence of these drugs on the capacity to produce interleukin-2 (IL-2) after phytohemagglutinin (PHA) induction has also been evaluated. Depending upon the nature of the stimulus used, differences were found among the three immunosuppressive drugs, suggesting that different T-cell activation mechanisms are involved. The response to alloantigens (MLR) or to mitogens (Con A and OKT3 MoAb) resulted in significant inhibition by all three immunosuppressive agents, although 6-mercaptopurine was somewhat less potent at the pharmacological concentration of 0.1 microgram/ml. When PMA (which activates cells through protein kinase C) and A23187 ionophore (which enhances Ca2+ influx into the cytoplasm through membrane channels) were used, dissociations were observed, suggesting that drugs act differentially on early stages of T-cell activation. Inhibition of PMA-induced activation by cyclosporin was very limited in contrast to the potent effect of methylprednisolone. The latter drug could thus preferentially affect an activation step involving the PMA receptor. Furthermore, the inhibitory influence of methylprednisolone on A23187 ionophore-induced proliferation was equivalent to that of cyclosporin, while 6-mercaptopurine had no effect except at the high concentration of 1 microgram/ml in which direct inhibition of DNA replication is probably involved. IL-2 production induced by PHA was strongly blocked by methylprednisolone and cyclosporin but not by 6-mercaptopurine, at least when a pharmacological concentration was used. In view of the relative independence of ionophore-induced activation from the influence of IL-2, this response could be linked to the intrinsic mechanism of antiproliferative activity of immunosuppressive drugs which probably act mostly at the level of IL-2 production. These results also provide a cellular approach to the synergies between immunosuppressive drugs. Most of the tests are more strongly affected by cyclosporin than by 6-mercaptopurine, probably explaining the potent steroid-sparing effect of cyclosporin.
Class II histocompatibility antigens were assessed by complement-dependent cytotoxicity on B enriched mononuclear cells and on purified monocytes isolated from the peripheral blood of renal patients before and after transplantation. After transplantation, a significant decrease of detection of DR alloantigens (cytotoxicity score before transplantation 3 +/- 0.1; after transplantation 0.95 +/- 0.1; p less than 0.001) was found. A similar defect was observed both on B enriched frozen cells and on purified monocytes isolated during the post-transplant period. Nevertheless, antigens could be adequately detected by a sensitive microabsorption method and by a procedure involving preincubation of mononuclear cells at 37 degrees C for 3 h followed by B cells enrichment by rosetting. The 37 degrees C induced reexpression could be inhibited by 10 micrograms/ml cycloheximide and by 50 microM monensin. No difference was found in the magnitude either of decreased expression or of temperature-induced reexpression between patients treated by CyS-Pred and those receiving Aza-Pred. It is concluded that transplanted recipients disclose a reversible defect of the expression of class II histocompatibility antigens probably related to perturbation of various steps of intracellular biosynthesis and traffic of these molecules.
In order to study the influence of iron overload on the polymorphonuclear leucocyte (PMN) metabolism of patients on chronic hemodialysis, generation of superoxide anion (O2-) by PMN in whole blood was compared in two groups of hemodialyzed patients: group A consisted of twenty-one individuals with serum ferritin levels above 1000 ng/ml and group B of nineteen individuals with serum ferritin levels below 1000 ng/ml. Whereas basal production of O2- was similar in the two groups (6.3 +/- 4.6 vs 11.5 +/- 8.3 nmoles O2- 10(6) granulocytes-1 15 min-1) (mean +/- s.e.m.), PMN response to opsonized zymosan was significantly lower in group A as compared with group B (86.5 +/- 6.3 vs 120.4 +/- 8.2 nmoles O2- 10(6) granulocytes-1 15 min-1) (p less than 0.01). Superoxide anion generation induced by the dialysis procedure was reduced in eight patients from group A (89.2 +/- 32.1) as compared with eight patients from group B (374.3 +/- 100.0 nmoles O2- 10(6) granulocytes-1 15 min-1) (p less than 0.05). These data suggest that iron overload may be involved in the impairment of neutrophil phagocytosis in patients on chronic hemodialysis.
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An immunogold staining procedure for light microscopic enumeration of peripheral blood lymphocyte subsets defined by monoclonal antibodies (OKT3, OKT4, OKT8, OKIa1, Leu 1, Leu 4, Leu 2a, Leu 3a, Leu 10, Leu 12, B1) is described. It uses colloidal gold-labeled goat anti-mouse Ig (GAM G40 and GAM G30) as second layer and a methyl-green pyronin counterstain. Performed on small volumes of blood without sophisticated laboratory equipment, this method allows accurate cell type recognition and permanent records, essential for longitudinal observations. By enumerating the gold particles on positively labeled cells, it was shown that the staining reactivity depended on the monoclonal antibody used. Lymphocytes reacting with OKT8 or OKIa1 or B1 exhibited the strongest labeling whereas OKT4+ cells were weakly labeled. When compared with flow cytometry analysis in healthy subjects, the accuracy, precision and sensitivity of both methods were very similar. Similarly, a close correlation (97%) was found between immunogold staining and immunofluorescence microscopy in 35 patients with various diseases suggesting that immunogold staining may be useful in a clinical context.
The clinical and cytogenetic findings of a patient with a preleukemic state and trisomy 11 are reported. Trisomy 11 was present as the sole karyotypic alteration at the time of overt leukemia. Trisomy 11 presents an additional chromosomal abnormality not previously described in preleukemia.
The levels of IgM, IgG and IgA were measured in the serum of 337 psychiatric inpatients (92 patients with bipolar depression, 150 patients with unipolar depression and 95 schizophrenics) and compared to 150 healthy subjects. A significantly higher level of IgM was found in all psychiatric groups compared with the controls, and IgM levels were more elevated in female patients than in male patients for the bipolar and unipolar groups. There were no differences for the other immunoglobulins (IgG, IgA) among the groups studied. In 51 of the patients (17 bipolar, 34 unipolar), other measurements were performed (C-reactive protein, antinuclear antibodies, lymphocyte antibodies, thyroid antibodies, complement and the third and fourth factors of complement). The unipolar group showed a significant rise of C-reactive protein values and the presence of antinuclear antibodies. Interestingly all patients with antinuclear antibodies were females. No difference was found between psychiatric patients and controls in lymphocyte antibodies, thyroid antibodies and values of complement.
This article summarizes some of the immunological activities of enkephalins and endorphins. Human and animal lymphocytes possess receptors for endorphins and enkephalins. These opioid peptides enhance T cell mitogen response. They decrease in vitro antibody formation. Endorphins and enkephalins will enhance human natural killer activity. This effect may be mediated by several mechanisms including the production of factor(s) enhancing natural killer activity by lymphocytes incubated in presence of opioid peptides. All these results suggest that opioid peptides may be activation molecules for the immune system and as such immunomodulatory agents.
Twenty patients with alopecia universalis, alopecia semiuniversalis and alopecia areata were studied for their immune parameters. Fourteen of them received an oral treatment with Isoprinosine, a synthetic immunomodulator. Ten patients showed the presence of several autoantibodies. No significant abnormalities in various T cell rosette markers were found, but T4/T8 ratios tended to be elevated. Erythrocyte antibody complement (EAC) rosettes were usually decreased. Treatment with Isoprinosine produced a clinical response, as judged by total or partial hair growth, in nine of the fourteen patients treated. It was striking to observe that seven of the nine responders had autoantibodies prior to treatment. These autoantibodies disappeared or decreased with Isoprinosine therapy. In contrast, only one of five nonresponders had serum autoantibodies. After treatment, both groups showed an increase in blood-active T rosettes. These results suggest that alopecia is a heterogeneous disease subdivided by the presence or absence of autoantibodies since clinical response was mainly obtained in patients presenting autoantibodies.
This paper introduces an immunogold silver staining procedure for the identification of human lymphocyte subpopulations in optical microscopy. The described procedure is performed on cells in suspension (peripheral mononuclear cells or blood buffy-coat cells) and uses conventional antilymphocytic monoclonal antibodies (OKT3, OKT4, OKT8, OKIa1) followed by gold-labeled secondary antibodies (GAM G30 or G40) and silver sensitization. It ends with the preparation of permanent records (smears or cytocentrifuge preparations) which are counterstained with standard panoptic Wright or May-Grünwald Giemsa stain. In all cases, the surface antigens appear as numerous black dots on the lymphocytes, with a strong labeling reaction that allows one to clearly distinguish between negative and positive cells. The comparison with immunofluorescence microscopy in normal individuals and in patients indicates that this new immunostaining technic is specific and more sensitive. It has the advantages of using small amounts of blood (1 mL per test), of being rapid (three hours), and of allowing the simultaneous immunophenotypic and morphologic evaluation on smears. This makes it suitable for the analysis of other biologic specimens not already accessible with immunofluorescence. The labeled preparations apparently can be stored indefinitely, and are thus useful for longitudinal studies in the same patient. Finally, the method does not require sophisticated equipment and may be subjected to automated analysis.
The influence in vivo of immunosuppressive drugs (cyclosporine, azathioprine, and corticosteroids) on the production of various lymphokines (alpha and gamma interferon, interleukin 2), both in organ transplant recipients and in normal volunteers taking 100 mg hydrocortisone orally has been studied. To avoid interference with the rejection process or viral infection, patients were studied in a steady state with low maintenance immunosuppression consisting of prednisolone combined with azathioprine or with cyclosporine. In patients treated with both drug regimens, significant depression of production of the three lymphokines was found. Normal volunteers challenged with 100 mg hydrocortisone showed inhibition of production of interleukin 2 and alpha and gamma interferon in 4 hr, a time corresponding to the nadir of T cell lymphopenia, affecting the OKT4 subset preferentially. The percentage of OKT8 cells remained unchanged. Percentages of large granular lymphocytes increased, but their absolute number was not significantly modified. Changes in lymphocyte markers were fully reversible after 24 hr, but interleukin 2 production remained markedly depressed, showing that the redistribution patterns induced by corticosteroids on lymphocyte subsets may be dissociated from functional consequences.
Human recombinant interferon-alpha 2C was given to 4 patients with essential thrombocythaemia. Three patients achieved a complete remission on day 19 +/- 1 and the 4th achieved a partial remission. After 4 weeks of induction therapy, a maintenance therapy of twice weekly intramuscular injections of 5 X 10(6) or 10 X 10(6) IU was instituted but did not maintain the remission.