PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Histocompatibility Testing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed1986

Joint report of the Third International Workshop on Canine Immunogenetics. I. Analysis of homozygous typing cells.

The Third International Workshop on Canine Immunogenetics involved 80 potentially DLA-D homozygous typing cells obtained from dogs of various breeds and submitted from five laboratories in Europe and the United States. Mutual reactivity of all cells was studied in mixed leukocyte cultures, and stabilized relative responses were used for analysis. Intralaboratory and interlaboratory comparisons of results suggest that a stabilized relative response of 30% represents an acceptable parameter for "typing responses" indicating phenotypic DLA-D identity of stimulator and responder cells. Using this criterion, 10 clusters of homozygous typing cells were defined and accepted on an international level, and they were assigned the specificities Dw1 to Dw10. At least six additional (provisional) specificities were recognized that were well characterized within individual laboratories but require additional testing before workshop specificities can be assigned. These data show that DLA-D typing is feasible and represents a useful tool in the genetic analysis of the canine major histocompatibility complex. Much work is needed to confirm the present results in family studies, to determine gene frequencies, and to analyze at a molecular level the antigens responsible for mixed leukocyte culture reactivity.

Animals↗
PubMed1976

Cellular and humoral immune response analysis of bone-allografted rats.

Long-term cellular and humoral immune responses were studied in inbred rats in which bone was allografted. Transplants were made across major histocompatibility barriers. Mixed lymphocyte culture tests and humoral cytotoxicity assays were performed in order to determine degrees of cellular and humoral immunity. Grafts of complete bone and of bone free of marrow elicited both types of immune response and it is proposed that transplantation antigens for both types of reaction exist in the bone tissue itself. A gene-dose effect was found. Allogeneic bone grafts gave a stronger reaction than semiallogeneic grafts, and second-set grafts triggered a hypersensitivity type of humoral immune response. This study suggests that until the host-bone graft immunological relationship is better understood, the graft tissue should be matched to the host for major transplantation antigens to help prevent unexpected failures in massive bone allotransplantation.

Animals↗
PubMed1999

Natural variation of the expression of HLA and endogenous antigen modulates CTL recognition in an in vitro melanoma model.

Increasing attention has been devoted to elucidating the mechanism of lost or decreased expression of MHC or melanoma-associated antigens (MAAs), which may lead to tumor escape from immune recognition. Loss of expression of HLA class I or MAA has, as an undisputed consequence, loss of recognition by HLA class I-restricted cytotoxic T cells (CTLs). However, the relevance of down-regulation remains in question in terms of frequency of occurrence. Moreover the functional significance of epitope down-regulation, defining the relationship between MHC/epitope density and CTL interactions, is a matter of controversy, particularly with regard to whether the noted variability of expression of MHC/epitope occurs within a range likely to affect target recognition by CTLs. In this study, bulk metastatic melanoma cell lines originated from 25 HLA-A*0201 patients were analyzed for expression of HLA-A2 and MAAs. HLA-A2 expression was heterogeneous and correlated with lysis by CTLs. Sensitivity to lysis was also independently affected by the amount of ligand available for binding at concentrations of 0.001 to 1 mM. Natural expression of MAA was variable, independent from the expression of HLA-A*0201, and a significant co-factor determining recognition of melanoma targets. Thus, the naturally occurring variation in the expression of MAA and/or HLA documented by our in vitro results modulates recognition of melanoma targets and may (i) partially explain CTL-target interactions in vitro and (ii) elucidate potential mechanisms for progressive escape of tumor cells from immune recognition in vivo.

Antibodies, Monoclonal↗
PubMed2004

Successful umbilical cord blood transplantation for Fanconi anemia using preimplantation genetic diagnosis for HLA-matched donor.

Fanconi anemia is a rare autosomal recessive disease characterized by bone marrow failure, developmental anomalies, and a high incidence of myelodysplasia and acute myeloid leukemia. Stem cell transplantation is the only curative treatment. In the absence of matched- sibling donor, an alternative mismatched family or matched unrelated donor can be used, but the results are inferior to the matched-sibling transplant and carry a high risk of morbidity and mortality. Preimplantation genetic diagnosis (PGD) has been increasingly used in recent years for mutation analysis for many genetic disorders and results in the birth of healthy children, saving the need for the termination of pregnancy of an affected embryo. The use of PGD for combined analysis of mutation and HLA-matching was reported for the first time in 2001. This enables the birth of an unaffected child who can serve as a donor for an affected sibling in need for stem cell transplantation. We report successful cord blood transplantation for a Fanconi anemia patient from his HLA-matched sibling, born after PGD that included mutation analysis for Fanconi anemia and HLA typing. PGD can provide an unaffected donor for a sibling affected by genetic disease in the absence of a compatible related donor.

Blood Donors↗
PubMed1976

Inducibility of the Epstein-Barr virus (EBV) cycle and surface marker properties of EBV-negative lymphoma lines and their in vitro EBV-converted sublines.

Two EBV-negative lymphoma lines of human B-cell origin, BJAB and Ramos, were compared with altogether six of their in vitro EBV-converted, EBNA- and EBV-DNA-carrying sublines (four of Ramos and two of BJAB derivation). All converted lines closely resembled the parental line with regard to karyotype and HL-A and B antigen typing. Induction of EBV antigens (EA and VCA) by P3HR-1 virus superinfection was either similar in the converted and the negative lines, or somewhat increased in certain converted lines. These findings argue against a simple, virally determined repressor model and emphasize the role or cellular controls in restricting the EBV cycle in virus-carrying B-lymphocyte lines of human origin. IUdR inducibility varied in the different converted lines. There was a possible relationship between average number of EBV-genome equivalents per cell and inducibility. Converted sublines did not differ from the original negative lines with regard to surface immunoglobulin and Fc receptors. There was a dramatic increase in complement-consuming ability, however, following EBV conversion. Among the EBV-positive lines, there was a linear relationship between complement-consuming and EBV-receptor activity, the latter measured by a quantitative absorption test.

Antigens, Viral↗
PubMed1996

Soluble CD8 antigen, stimulated C-peptide and islet cell antibodies are predictors of insulin requirement in newly diagnosed patients with unclassifiable diabetes.

To evaluate the predictive factors of insulin requirement in newly diagnosed patients with unclassifiable diabetes, 54 consecutive patients, aged less than 35 years, were prospectively followed for 3 years or more. At entry, haemoglobin HbA1c, basal and stimulated C-peptide concentrations, HLA phenotype, islet cell antibodies (ICA) status, and serum levels of soluble CD8 antigen (sCD8) were evaluated. After a median time of 9 (range 2-32) months, 31 patients (group 1) required insulin therapy, whereas 23 patients (group 2) remained non-insulin-requiring after 36 months. Group 1 patients were younger (P < 0.05) and had higher HbA1c and sCD8 serum levels (P < 0.0001), respectively), a higher frequency of ICA positivity and of HLA DR3 and/or DR4 phenotype (P < 0.005 and P < 0.0001, respectively), and lower C-peptide concentrations (P < 0.005 and P < 0.0001, basal and stimulated, respectively) than group 2. The sensitivity, specificity, positive and negative predictive value, and overall accuracy for the subsequent insulin requirement were: sCD8 serum levels (> 737 U/ml), 100%, 65%, 79%, 100% and 85%, respectively; stimulated C-peptide (< 0.60 nmol/l), 71%, 96%, 96%, 74% and 81%, respectively; and ICA positivity (> 20 JDFU), 45%, 91%, 87%, 55% and 65%, respectively. Thus, higher sCD8 serum levels, low stimulated C-peptide concentrations and ICA positivity are the most powerful predictors of subsequent recourse to insulin therapy in young, newly detected patients with unclassifiable diabetes.

Adolescent↗
PubMed1999

Detection of HLA-E and -G DNA alleles for population and disease studies.

HLA-E and -G genes show a restricted polymorphism encoding for molecules whose variability is limited at the peptide binding site. Fourteen alleles that give rise to only three productive proteins for HLA-G (*0101, *0103 and *0104) and five alleles with three different proteins for HLA-E (*0101, *0102 and *0103) have been described. Expression of these molecules is low and found in many tissues for HLA-E: HLA-G protein is expressed in extravillous trophoblast cells and thymic epithelium. Molecular studies have shown how HLA-G and HLA-E bind to natural killer (NK) cells immunoglobulin and lectin-type inhibitory receptors. HLA-E may act as a sentinel of the cell; if classical class I and HLA-G are being expressed, HLA-E molecules may reach the cell surface and inhibit the lysis by NK cells. Most findings are consistent with the hypothesis that HLA-E and -G proteins may be tolerogenic molecules at either the T-cell receptor (TcR) (inflammation, graft rejection) or NK level, switching off cells which usually attack foreign (including foetus) or self (autoimmune) antigens. A low HLA-E and -G polymorphism is observed in humans, and their allele frequencies are mostly homogeneous in the populations tested so far. Many studies to detect these alleles are now being performed in isolated populations and also in pregnancy-associated pathologies. In the present paper, standard and detailed techniques to detect HLA-E and -G DNA polymorphism are reported and discussed.

Alleles↗
PubMed2000

Complement activation by anti-endothelial cell antibodies in MHC-mismatched and MHC-matched heart allograft rejection: anti-MHC-, but not anti non-MHC alloantibodies are effective in complement activation.

Classical complement activation is a major effector mechanism in the development of vascular lesions contributing to allograft rejection. We investigated complement activation by alloantibodies reactive with graft endothelial cell (EC) alloantigens in settings of MHC-mismatched and MHC-matched (non-MHC-mismatched) rat heart transplantation (Tx). Allosera and heart allografts were collected at the day of rejection (day 7-8 and day 28-35 in MHC-mismatched and non-MHC-mismatched Tx respectively) or earlier. Allosera reactivity was studied in vitro using rat-heart-endothelial-cell (RHEC) lines expressing the appropriate donor MHC and non-MHC alloantigen profile. Immunohistochemical analysis of rejected heart allografts showed deposition of alloantibodies in both MHC-mismatched and MHC-matched heart allografts, but expression of C3 was only seen in the vasculature of MHC-mismatched grafts. FACS analysis showed that anti MHC as well as anti non-MHC allosera were reactive with donor EC cell surface antigens. Both sera had similar IgG subclass profiles of anti-endothelial cell antibodies. Complement activation by anti MHC and anti non-MHC alloantibodies on EC was measured by FACS analysis of C3 and C5b-9 (MAC) expression. Distinct expression of C3 was noticed for EC incubated with anti-MHC allosera, but hardly for EC incubated with anti non-MHC allosera. C5b-9 was low but showed no difference between the two allosera. However, complement-mediated cytotoxicity experiments showed that functional (lytic) MAC was induced with anti MHC allosera but hardly with anti non-MHC allosera. Our data show that in settings of MHC-matched heart transplantation alloantibodies against endothelial non-MHC alloantigens are generated, but, in contrast to alloantibodies to MHC alloantigens, these alloantibodies have only poor complement-activating and lytic potentials. Whether anti non-MHC allolantibodies effect other biological processes relevant for heart allograft vasculopathy, including development of graft arteriosclerosis, needs further elucidation.

Animals↗
PubMed1995

The cytotoxic HLA-DQ3 reactive human hybridoma antibody 4166 that may distinguish DQ7 + 8 from DQ9.

The human cytotoxic hybridoma antibody 4166 (IgM kappa) was generated by fusing an in vitro EBV-transformed B-LCL from a multiparous woman with the mouse-human heteromyeloma fusion partner CB-F7. In microcytotoxicity and IIF tests with B-LCLs as target cells, the mAb 4166 was specific for DQ3 (= DQ7 + 8 + 9). However, when used for DQ typing of class-II-positive PBMCs, 4166 could be rendered functionally specific for DQ7 + 8 and did not react with DQ9+ PBMCs. Binding of mAb 4166 to DQ8-positive cells was efficiently blocked by several allotype-specific mAbs recognizing DQ8. Other HLA class-II-specific mAbs were unable to inhibit. With the use of mAb 4166, it is possible to discriminate DQ7 + 8 from DQ9 in serologic DQ typing.

Amino Acid Sequence↗
PubMed1995

Detection of antilineage specific leucocyte antibodies by a quantitative immunocytometry method in sera from candidates for renal allografts.

A sensitive and quantitative flow cytometry method for detecting antileucocyte antibodies was developed to study retrospectively samples from candidates using frozen donor cells and frozen recipient sera. This immunofluorescence method was used to compare levels of reactivities of serum antibodies before and after donor specific blood transfusion treatment and after renal transplantation. The results demonstrate that the flow cytometry crossmatch is a sensitive and accurate method which should be used prospectively before precluding transplantation in the presence of a positive B cell standard crossmatch. Antibodies detected by flow cytometry before transplantation could be responsible for an early acute rejection episode. Finally, combination of flow cytometry crossmatch and standard crossmatch assays might thus be useful before precluding transplantation in living related donors.

Adolescent↗