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Biomedical subjects

M Buc

Publications and source records attributed to M Buc.

At least 55 records · Page 3Linked to original sources
PubMed1993

The major histocompatibility complex in man.

The HLA system is a complex of polymorphic genes divided into a class I group and a class II group. The disclosed tertiary structure of HLA antigens indicates that they are principally involved in binding a variety of self and foreign immunogenic peptides and in their presentation to T cells. Class III HLA region is located between class I and class II regions. It comprises many genes, some of them participate in events of the immune response, too.

Antigen Presentation↗
PubMed1993

The role of HLA-DQ antigens in the induction of cytotoxic T lymphocytes.

Investigating three pairs of HLA-DR (DRB1) identical unrelated persons on the induction of cytotoxic T lymphocytes (CTL) it was found that HLA-DQ antigens provided slight proliferative stimulus which was, however, sufficient for the generation of CTL. The results indicate that the HLA-DQ antigens do play a similar role in clinical bone marrow transplantation as the HLA-DR specificities.

Bone Marrow Transplantation↗
PubMed1993

[Immunogenetics and immunologic aspects of kidney and bone marrow transplantation].

Progress in comprehension of the immunogenetics of the HLA-complex and the discovery of new very potent immunosuppressive agents have enabled organ and tissue transplantations to be performed as a relatively routine therapeutic method. Long-term outcome measured as a half-life in kidney transplantations is 25 years among HLA-identical siblings, 12 years in one haplotype-mismatched paternal donors, and 7 years in cadaver transplantation program. The long-term outcome in the latter group can be markedly improved--to as much as 19 years--when six-antigen program is observed (i.e. donor and recipient are identical in HLA-DR, -B, and -A antigens). The survival of patients after bone marrow transplantation (BMT) having as a donor a HLA-identical sibling has improved remarkably, too. However, only about 30 percent of patients who might benefit from a bone marrow transplant have a genotypically. HLA-identical sibling who could be a donor. Transplants from unrelated donors have become therefore an alternative method. To find HLA-matched donors the establishment of large registries are needed. One of them--Them Bone Marrow Donors Worldwide--in Leiden has over 1.2 million of potential donors at the time being (1992).

Bone Marrow Transplantation↗
PubMed1992

[The HLA complex in 1991].

In November 1990 the Nomenclature Committee of the WHO updated the designation of loci, alleles, and antigens of the HLA complex. Their complete list is presented in our review, along with current knowledge on the complexity of the HLA-D region. Finally, the paper deals with the tertiary structure of HLA antigens discovered in 1987, which has enabled us to understand the biological significance of the HLA complex. (Fig. 5, Tab. 5, Ref. 15.)

HLA Antigens↗
PubMed1991

Reduced expression of HLA-DP antigens on PWM stimulated T lymphocytes in patients suffering from psoriasis vulgaris.

24 psoriasis vulgaris patients were investigated for the expression of class II HLA antigens on the surface of PWM-stimulated T lymphocytes. The percentage of the expression of HLA-DP antigens ranged from 50.1% to 82.6% compared to a 100% level in healthy controls (p less than 0.005). No significant differences in the expression of HLA-DR antigens were observed. A higher frequency of some HLA antigens was found in the group of patients studied: B13 - 23.1%/6.2%, B 17 - 15.4%/7.1%, and Dw7 - 59.4%/15.8%.

Concanavalin A↗
PubMed1990

[Possibilities of finding identical HLA donor-recipient pairs for bone marrow transplantation].

With the aim to detect genotypically identical donors for patients suffering from some type of leukemia or aplastic anemia, HLA antigens and MLC reactivity were determined in 72 families, having together 209 children. HLA identical, MLC negative sibling donors were found for 31 patients, i.e. 43%. Compared to the healthy population, no significant differences were found in the frequency of HLA antigens and haplotypes in 58 leukemic patients. Two recombinations were recorded, one between the loci HLA-A and HLA-B, and the other one between HLA-B and HLA-D/DR. Only 9 persons (2.5%) homozygous for HLA-D antigens were found in the whole series of 353 subjects investigated.

Bone Marrow Transplantation↗
PubMed1990

Occurrence rate of the HLA-identical pair donor-recipient for bone marrow transplantation.

HLA antigens and MLC reactivity were ascertained in 69 families, having altogether 198 children, with the aim to find genotypically identical donors for patients suffering from some type of leukemia or aplastic anemia. HLA identical, MLC negative sibling donors were found for 29 patients, i.e. 42.03%. In 55 leukemic patients the frequency of HLA antigens and haplotypes was calculated. No significant differences were found as compared to the healthy population. One recombination between HLA-A and HLA-B and one between HLA-B and HLA-D/DR loci were observed.

Bone Marrow↗
PubMed1989

[The effect of certain substances on changes in the expression of class II HLA antigens].

With the aid of the RIA method, the authors found that the stimulation of T-lymphocytes by means of PWM lectin is linked to the expressivity of HLA antigens of class II on their surface. A simultaneous addition of indomethacin, tetracycline, coreton, hydrocortisone and novozir was decreasing the expressivity of the Ia antigens and, at the same time inhibited the lymphocyte proliferation. The growth factor for T (IL-2) lymphocytes was increasing the expressivity of HLA-DR antigens in the cells even without a previous stimulation by mitogen. Glucan, serous thymic factor, natrium salicylicum, hippuric acid had no effect on the expressivity of the HLA antigens of class II.

HLA-D Antigens↗
PubMed1989

Family study of natural killer cell activity in C1q-deficient patients with systemic lupus erythematosus-like syndrome: association between impaired natural killer cell function and C1q deficiency.

Impaired natural killer (NK) cell activity has been found in patients with systemic lupus erythematosus (SLE)-like syndrome. The mechanism by which NK cell function is impaired in SLE patients is not quite clear. We report here a family study of NK cell activity in C1q-deficient patients with SLE-like syndrome. In both SLE-active and SLE-inactive stages of the disease, NK cell function was significantly impaired when compared with the healthy controls (10.6 +/- 2.3% and 16.9 +/- 4.8% to 34.7 +/- 9.6%, p less than 0.025). On the other hand, differences in NK cell cytotoxicity between SLE-active and SLE-inactive members of the family were not statistically relevant (p less than 0.1). Further, we found no correlation between NK cell activity and clinical or laboratory values, except for a positive correlation between function of NK cells and C1q and CH50 values, respectively (rs = 0.93, 0.01 less than p less than 0.02). To our knowledge, this is the first report on a notable association between impaired NK cell activity and C1q deficiency. The type of inheritance of C1q deficiency in this family is also discussed.

Adult↗
PubMed1989

[Specific cell-mediated cytotoxicity in patients with cerebral infarct].

The purpose of the work was to assess changes in the activity of cytotoxic lymphocates in patients with cerebral infarction. The material comprised 27 patients with the diagnosis of cerebral infarction and 18 controls. The authors analyzed the activity of cytotoxic lymphocytes, against the cerebral antigen-encephalitogenic peptide (EP). As target cells they used syngenic lymphocytes coated with EP and labelled with 51Cr, the activity of which released during reaction with supernatan is proportional to the amount of cells disrupted by cytotoxic lymphocytes. The reaction is specific for the encephalitogenic peptide. The activity of specific cytotoxic lymphocytes was in patients with cerebral infarction almost four times higher than in controls. The percentage activity was higher in "seriously affected patients" and two weeks after the onset of the disease. Then the activity declined. Investigation of the activity of cytotoxic lymphocytes could prove important in patients with cerebral infarction with symptoms of sensitization against cerebral antigen.

Adult↗
PubMed1989

HLA-D/DR identity results in a positive CML reaction.

Investigating HLA-A, HLA-B, HLA-C, and HLA-DR antigens, MLR, CML, and PLT reactivity in two unrelated persons it was found that despite their HLA-D/DR identity cytotoxic T lymphocytes (CTL) could be induced in the CML assay. The HLA-DP antigens proved to provide the necessary proliferative impetus for the generation of CTL.

Cytotoxicity, Immunologic↗
PubMed1989

A review: HLA and diseases--current status.

Since the discovery of polymorphism of the HLA complex the relationship between HLA antigens and various diseases has been followed. A number of HLA disease associations have been found. A review of the most important ones is given in this article. Explanation of the relations: "HLA and diseases" remains obscure till now what however does not hinder to take profit from them in practical medicine at diagnosis, differential diagnosis, therapy, prevention and also in genetic advisory service.

Endocrine System Diseases↗
PubMed1989

[Myocarditis in childhood].

In a group of 82 children followed up for prolonged periods the authors draw attention to some problems of virus myocarditis. They focused attention on the diagnosis of Coxsackie myocarditis for which they elaborated a scoring system. Based on this system they separated the prognostically most adverse group where cardiac decompensation was the dominant sign from the very beginning. They confirmed the theoretical assumption that in some children virus myocarditis develops into cardiomyopathy. This was proved in six children by histological examination and in 19 children by means of echocardiography.

Child↗
PubMed1989

[The development of cytotoxic T lymphocytes in HLA-D/DR identity].

The development of cytotoxic T-lymphocytes is controlled by genes of the HLA complex and occurs, in the majority of cases, when the responding and stimulating subjects differ both in HLA-A, -B and HLA-D/DR antigens. We examined a married couple for kidney transplantation and found that they differed in HLA-A, -B antigens and were identical in HLA-DR antigens. The negative results of the MLC test confirmed the serological findings. Nevertheless, cytotoxic T-lymphocytes developed despite HLA-D/DR identity. The presented case is one of the few published exceptions to the rule governing the development of cytotoxic T-lymphocytes.

Cytotoxicity Tests, Immunologic↗
PubMed1989

[Expression of HLA antigens using the radioimmunoanalysis method].

Expression of HLA antigens class II on stimulated T lymphocytes was studied by radioimmunoassay. The products of all three HLA loci --DR, --DP, --DQ were present on stimulated cells in contrast to resting control T lymphocytes which do not express these antigens and are Ia negative.

HLA-D Antigens↗