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Biomedical subjects

J Y Muller

Publications and source records attributed to J Y Muller.

At least 109 records · Page 6Linked to original sources

HLA antigens on peripheral red blood cells: analysis by flow cytofluorometry using monoclonal antibodies.

The presence of HLA (class I) determinants on red blood cells was found in 15% of individuals of the French population. This percentage varies considerably from one geographical region to another in the world. The red blood cells (RBC) that express class I determinants also express beta 2 microglobulin but not HLA-DR antigens. This phenomenon does not appear to be linked to the erythrocyte phenotype nor to the HLA phenotype of the subject. Cytofluorometry analysis allowed us to establish that the large individual variations in the expression of the HLA antigens on RBC are related mainly to the percentage of positive cells but not to the fluorescence intensity of each cell. A comparative study between platelets and red blood cells showed that the expression (i.e. antigen density) of HLA class I determinants is weaker on red cell membrane.

Antibodies, Monoclonal↗

[Abnormal regulation in the production of IL2 in Hodgkin's disease].

Patients with active Hodgkin's disease demonstrate a significant depression of cellular immunity. The present study, performed with lymphocytes from 16 untreated patients with active Hodgkin's disease and 13 healthy control volunteers, demonstrate an equivalent IL 2 production in vitro in both groups. Our results, however, demonstrate an abnormal regulation of IL 2 production in patients. A negative control of IL 2 production involving monocytes producing PGE 2 able to induce radiosensitive suppressor T lymphocytes, has been identified previously with cells from healthy donors. In the present study we demonstrate that this negative control is hyper functioning with cells from Hodgkin's disease patients.

Hodgkin Disease↗

Identification of several functional subgroups of HLA-B27 by restriction of the activity of antiviral T killer lymphocytes.

Anti-Epstein-Barr virus and antiinfluenza A cytotoxic T lymphocytes (CTL) have been used to study the restriction of human antiviral responses by HLA-B27 antigens. Three functional subgroups of HLA-B27 have been clearly distinguished by this "restriction-typing assay". No cross-reaction could be detected between the three subgroups either at the CTL level or at the level of antigen-presenting cells. The cells of subgroup 1 are always positive [M2(+)] when tested in immunofluorescence with a monoclonal B27-specific antibody which divides HLA-B27 into a major M2(+) and a minor M2(-) subgroup. These M2(+) group 1 cells are apparently also HLA-B27W as previously shown by Ivanyi and co-workers using anti-HLA-CTL. Subgroup 2 includes only M2(-) cells. A comparison between this group and the previously described HLA-B27K is not fully conclusive, since two typing cells which were clearly HLA-B27K apparently did not belong to group 2. Only two donors, both of Oriental origin, have been included in subgroup 3. Both of them were "M2 intermediate". These results demonstrate (1) the existence of several functional subgroups of HLA-B27 with an interesting correlation with the M2(+), M2(-), or M2 intermediate phenotypes, and (2) the possibility of using the restriction-typing assay to define such functional subgroups not detected by classical allosera.

Antibodies, Monoclonal↗

[Acquired immunodeficiency syndrome. Measures to be taken in blood transfusion establishments in order to protect the personnel].

There is presently no evidence of AIDS transmission to laboratory workers. Because transmissible agent is suspected, precautions should be taken in laboratories. As a general rule, procedures appropriate for hepatitis B prevention are advised. These procedures concern blood collection, carrying, and processing. Measures should be taken in order to avoid blood spilling and work surfaces should be decontaminated. Disposable material should be preferred, and all potentially contaminated material should be decontaminated before disposal or reprocessing. All personnel should be aware of usual laboratory procedures concerning pipetting, hand washing, protective clothing and of general precautions against viral contaminations.

Acquired Immunodeficiency Syndrome↗

HLA-DR locus and maternal-foetal relation.

Antigen HLA-A, B sharing couples have been previously observed in abnormal pregnancies of unknown etiology. We have determined the HLA-A, B, C and DR antigens of 20 couples with recurrent spontaneous abortions (RSAs), 32 control couples and 100 normal controls. The results showed that in couples with more than two idiopathic repeated abortions, there is no significant increase in the HLA antigen sharing couples. But we were able to observe, in the affected couples, a significant increase in HLA-DR antigen sharing as regards the control couples. We also find a significant increase in the DR5 antigen, in both wives and husbands, in couples with repeated abortions of unknown etiology as previously described for the Dw5 antigen.

Abortion, Habitual↗

Polymorphism of HLA class I genes after restriction by endonucleases Eco RI, Eco RV and Hind III.

After electrophoresis and transfer onto a hybridization membrane, the restriction endonuclease fragments obtained were probed with a cDNA carrying the nucleotide sequence encoding a class I HLA gene. Polymorphism for presence or absence of various Eco RI and Eco RV and Hind III fragments was noted in a panel of unrelated Parisian people: frequent polymorphism was described for 2 Eco RI restriction fragments of sizes 16.5 and 7.7 kb, for 5 Eco RV restriction fragments of sizes 25, 20, 11.5, 7.8 and 4 kb, and for 3 Hind III restriction fragments of sizes 27.5, 23.5 and 4.7 kb. The French population studied is in Hardy-Weinberg equilibrium for the different variants described.

DNA Probes↗

Klebsiella plasmid K21 is not involved in the aetiology of ankylosing spondylitis.

The possibility that a plasmid carried by Klebsiella pneumoniae plays a role in the pathogenesis of ankylosing spondylitis was explored. K. pneumoniae K21 contains a congruent to 25-kb plasmid, but this plasmid is not present in lymphocyte DNAs of ankylosing spondylitis HLA-B27 patients, as demonstrated by molecular hybridization experiments.

Blotting, Southern↗

Familial idiopathic membranous glomerulonephritis.

2 brothers with identical HLA antigens presented an idiopathic membranous glomerulonephritis. This is, to our knowledge, the first report of familial membranous glomerulonephritis. The fact that both brothers had identical HLA antigens suggests a genetic predisposing background.

Adolescent↗

Improved culture conditions for quantitative evaluation of interleukin 2 production by frozen human lymphocytes.

Several culture parameters were studied in order to establish methods for optimal and reproducible production of interleukin 2 (IL2) by thawed lymphocytes. Standard conditions, considered optimal for production by freshly separated lymphocytes (culture medium RPMI 1640 + 1% normal human serum + 10 micrograms/ml PHA), gave low and poorly reproducible results. An increased concentration of human serum (10 and 20%) in the medium improved production but best results were obtained by adding polyethylene glycol (PEG 6000, 0.1 mg/ml) to the culture medium. Furthermore, with the addition of PEG 6000, results became highly reproducible, thus permitting valid comparison of in vitro IL2 production by lymphocytes from normal donors and patients.

Blood↗

[Estimation of platelet-bound IgG by means of a test using radioactive antiglobulin].

A method of evaluation of platelet bound IgG (PA IgG) is described. This method rely upon the fixation of a radio-labelled goat anti-human IgG on platelets. Each new batch of labelling of the antiglobulin is tested with a reference system using a semi-purified anti-D IgG and O R1R1 and O rr erythrocytes. This system is used for the standardization and the validation of the antiglobulin, and it allows to make correspond an amount of antiglobulin to a known quantity of IgG molecules. The normal level of PA IgG in 98 healthy controls was found to be 351 +/- 252 antiglobulin combining sites (ACS) per platelet. The upper limit (99% confident limit) in the controls is 999 ACS per platelet. 412 thrombocytopenic patients have been tested, 78.7% of ITP had an elevated PA IgG. However positive results are also frequent in other thrombocytopenia even when an immune mechanism cannot be evoked. These positive results raise the problem of the signification of PA IgG and of their exact nature. Further dates are necessary to ascertain the role of auto-antibodies, immune complexes or of platelet membrane modifications in PA IgG increase.

Adult↗

An immune response gene linked to MHC in man.

With a view to finding a relationship between immune response and MHC in man, 83 D negative mothers with allo-into-D antibodies and 26 PLA1 negative mothers with allo-anti-PLA1 antibodies were investigated as regards their HLA-A, B and DR antigens. We have found that there is a highly significant relation between the DR3 antigen and an immune response to the PLA1 antigen, but none to the D antigen.

Gene Frequency↗

[Neonatal thrombopenia caused by antiPLA1 and HLA-DR3 antigen alloimmunization].

The HLA typing of mothers alloimmunised against the PLA1 antigen of their thrombocytopenic neonate shows that the A1, B8, DR3 haplotype is involved. The very strong association found with DR3 (20/21) suggests that an immune response gene located in the D region of the major histocompatibility complex might be responsible for the ability to develop an anti PLA1 antibody.

Adult↗