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M J Giphart

Publications and source records attributed to M J Giphart.

At least 55 records · Page 3Linked to original sources
PubMed1994

Tumor necrosis factor alpha-308 gene variants in relation to major histocompatibility complex alleles and Felty's syndrome.

The location of the human TNF genes within the MHC complex has prompted much speculation about the role of TNF alleles in the etiology of MHC-associated autoimmune diseases. On sequencing the 5' regulatory region of the human TNFA gene a G (TNFA-308G) to A (TNFA-308A) transition polymorphism at position -308 was discovered. We have developed a simple PCR assay to facilitate the screening of the -308 polymorphism at the DNA level. In view of the possible linkage between the TNFA-308A allele and a certain MHC type, TNFA-308 genotypes in HLA-typed healthy individuals (n = 88) were determined. A statistically significant association between the TNFA-308A allele and HLA-DR3, DQB1*0201, DQA1*0501, A1, B8, and the NcoI 5.5-kb RFLP of the TNFB gene was observed. In addition, we determined the frequency of the TNFA-308A allele in patients with FS (n = 13), an HLA-DR4-associated disease. In this study, no association was found of Felty's syndrome with the TNFA-308A allele, indicating that this allele does not appear to be a susceptibility factor for FS.

Alleles↗
PubMed1994

Asian Indian HLA-DR2-, DR4-, and DR52-related DR-DQ genotypes analyzed by polymerase chain reaction based nonradioactive oligonucleotide typing. Unique haplotypes and a novel DR4 subtype.

We have employed a PCR-based nonradioactive technique using biotinylated SSOPs to define HLA-DR2-, 4-, DR51-, and DR52-associated DR-DQ genotypes in Asian Indian families. In the DR2 group, most haplotypes described by us in a previous study were confirmed by family analysis. Evidence for one additional haplotype was available in this study. The classic DRB1*1501- and DRB1*1502-associated caucasoid haplotypes occurred with an appreciable frequency in Asian Indians, but two of the DRB1*1601-associated Caucasoid haplotypes were absent. At least six unique and unusual DR2-associated genotypes were encountered. In the DR52 group, the three most common alleles are DRB1*0301, DRB1*1404, and DRB1*1101. The DR6-associated alleles were DRB1*1301, 1302, 1401, and 1404. A few unique haplotypes occurred with low frequency in this group. In the DR4 group, at least three unusual patterns of hybridization were noticed by family analysis. One of these appears to be a novel DR4 subtype upon sequencing. These results demonstrate that, besides HLA-DR2, appreciable complexity occurs in the DR4- and DR52-associated alleles among Asian Indians. The presence of unique DR-DQ haplotypes in addition to those found characteristically among Western Caucasians suggests that the Indian population provides valuable source of many HLA class II haplotypes.

Amino Acid Sequence↗
PubMed1993

Biotinylated DRB sequence-specific oligonucleotides. Comparison to serologic HLA-DR typing of organ donors in eurotransplant.

A novel HLA-DR typing method was applied using PCR-amplified fragments and biotin-labeled oligonucleotides (PCR-biotin-SSO). The PCR-biotin-SSO method can be used efficiently to perform HLA-DR typing for a large number of individuals when time is not the limiting factor. The reliability of HLA typing of cadaveric organ donors is of vital importance for organ exchange organizations such as ET. Due to lack of time, these typings are usually performed by the complement-dependent cytotoxicity. The individual donor center typings are immediately reported to ET, where the recipient selection procedure is started. DNA isolated from donor spleen material, sent to the ETRL for retyping purposes, was subjected to PCR-biotin-SSO typing. The results were compared with the serological HLA-DR typings as reported to ET. The analysis of 1052 donor samples for the broad DR1-DR10 antigens revealed a concordance rate of over 90% between the donor center and the ETRL. The majority of the discrepancies involved specificities of the HLA-DR5, DR6, and DR8 cross-reacting group, with DR6 as the predominant discordant specificity. The results indicate (a) that PCR-biotin-SSO is a reliable technique for DNA-based HLA-DR typing and (b) that HLA-DR serology is still a useful technique when time is limited, such as for cadaveric donor typing.

Base Sequence↗
PubMed1993

Characterization of 4AOHW cell line panel including new data for the 10IHW panel.

There will be a continuing need for well characterized panels of EBV-transformed lymphoblastoid cell lines. Selection of the 4AOH panel was based on prior MHC typing and was intended to ensure representation of ancestral haplotypes from various racial groups. Cells from nonhuman primates, bone marrow donor-recipient pairs, and patients with IDDM were included. Selected cells from the 10IHW were included to enable further characterization. Cells were distributed to participants in the 4AOHW and were typed at multiple loci by a variety of procedures. Non-HLA genes such as TNF were included. Since the cells were distributed "blind" with hidden replicates, it was possible to evaluate the quality of the typing data. An approach to data management is described. The best current estimates of the typing of these cells are presented. The panel will be useful since it provides standards for most alleles at most loci. Since the cells are so well characterized, they represent a useful resource for MHC sequencing and for the evaluation of new typing procedures.

Alleles↗
PubMed1993

Microsatellite, restriction fragment-length polymorphism, and sequence-specific oligonucleotide typing of the tumor necrosis factor region. Comparisons of the 4AOHW cell panel.

The location of the TNF and other genes in the central MHC and their possible relevance to disease susceptibility provided an impetus to develop useful typing markers. The 4AOHW undertook to assess the various markers available, including DNA sequence-based systems. A panel of well-characterized lymphoblastoid cell lines were typed by Nco I RLFP analysis, SSO typing, and TNF microsatellite typing. RFLP and SSO typing were relatively reproducible as judged by the blind replicates. The two techniques provided the same results with only one exception, and it would be reasonable to prefer SSO typing because of its advantages in terms of cost and time. Microsatellite typing was much more discriminating but, as expected, less robust in that some discrepancies were apparent. As a result of the workshop and subsequent testing, alleles and haplotypes were allocated to most cells within the 4AOHW panel, including 10W cells typed in previous studies. While there was evidence that microsatellites may be relatively stable, they have the potential to identify recent mutations within ancestral haplotypes.

Artifacts↗
PubMed1993

Laboratory procedures used to select an unrelated HLA matched bone marrow donor.

Selecting an HLA matched unrelated bone marrow donor is a labour-intensive step-by-step procedure, with highly specialized techniques. To be successful immunohematologists and clinicians have to work closely together. Because so much is still unknown lymphocytes and serum of patient and donor should be stored to enable future analyses.

Bone Marrow Transplantation↗
PubMed1992

Relative contribution of HLA-DQA and -DQB alleles to predisposition to insulin-dependent diabetes mellitus.

The presence of DQA and DQB alleles conferring protection or susceptibility was assessed in a panel of 39 insulin-dependent diabetes mellitus patients and 39 healthy control subjects from the central highland of Ethiopia. The results were grouped into three entities: a combination of alleles conferring susceptibility, a group conferring protection, and a group without any apparent HLA-DQ or -DR predisposition to insulin-dependent (type 1) diabetes mellitus (IDDM). Statistical analysis revealed that the relative risk of the first group is 64.1. If a similar approach is applied to the data on a study in caucasoid IDDM patients and controls of Kahlil and colleagues, the pattern is fully consistent with the data presented here, with an extraordinarily high relative risk (RR 258.2). It will be of interest to study whether this subdivision is reflected or supported by clinical or etiologic differences of the disease. The predictive value of susceptibility phenotypes appears to be more accurate by the proposed subdivision. Furthermore, in combination with islet-cell antibody analysis, assessment of genotype will permit more accurate identification of prediabetic individuals to be entered in clinical trials.

Alleles↗
PubMed1992

Properdin factor B and complement factor C4 allotypes in rheumatoid arthritis: results of a follow-up study.

The association between allotypes of properdin factor B (Bf), the fourth component of complement (C4A and C4B), and rheumatoid arthritis (RA), was investigated in a well-characterized cohort of RA patients who were followed from an early phase of the disease for a mean duration of 6 years. The frequencies of probable heterozygous C4AQ0 and of C4A3 were lower in RA patients compared to controls, irrespective of the presence of DR4 [relative risk (RR): 0.52 and 0.49, respectively, 95% confidence intervals (95% CI): 0.34-0.80 and 0.29-0.82]. The frequency of C4A4 was higher in RA patients compared to controls (RR: 1.86, 95% CI: 1.03-3.35), especially in DR4 positive RA patients compared to DR4 positive controls (RR: 2.58, 95% CI: 1.07-6.25), indicating a positive association of this allotype with RA additional to DR4. Bf and C4B allotypes were comparable in RA patients and controls. We did not find significant differences in Bf and C4 allotype frequencies in RA patients subdivided according to severity of the disease into a mild group and a progressive group. Because of inconsistent results in all studies on Bf and C4 allotypes, we conclude that C4 and Bf allotypes do not seem to have an important independent effect on determining disease susceptibility.

Adult↗
PubMed1991

Positive correlation between oligonucleotide typing and T-cell recognition of HLA-DP molecules.

The identification of 19 different HLA-DPB1 sequences implicates the existence of more DP specificities than can be typed for with cellular methods. How many of the DP beta sequences can be specifically recognized by T cells, and which of the polymorphic regions can contribute to the specificity of allorecognition, is not known. In order to investigate the distribution and the immunological relevance of recently described DPB1 alleles, we have typed a panel of 98 randomly selected Dutch Caucasoid donors for the HLA-DPB1 locus by oligonucleotide typing. Comparison of the typing results with primed lymphocyte typing (PLT) defined DP specificities shows an extremely good correlation. Moreover, additional alleles could be defined by oligonucleotide typing reducing the number of DP blanks in the panel. By selecting the appropriate responder stimulator combinations we were able to show that distinctive PLT reagents against oligonucleotide defined specificities DPB1*0401, DPB1*0402, DPB1*0901, and DPB1*1301 can be generated. To investigate in more detail which part of the DP molecule is responsible for the specificity of T-cell recognition, T-cell clones were generated against HLA-DPw3. The clones were tested for the recognition of stimulators carrying DPB1 alleles which had been defined by oligonucleotide typing and sequence analyses and which differed in a variable degree from DPB1*0301. The recognition patterns demonstrated that differences of one amino acid in polymorphic regions situated either in the beta sheets or alpha helix of the hypothetical model of the HLA class II molecule can eliminate T-cell recognition. Furthermore, sequence analyses revealed a new DPB1 allele designated DPB1*Oos.

Alleles↗
PubMed1991

Analysis of HLA-DR2-associated polymorphisms by oligonucleotide hybridization in an Asian Indian population.

Among major histocompatibility complex class II antigens, HLA-DR2 appears to have a much larger degree of polymorphism than usually recognized by routine serology or restriction fragment length polymorphisms. We have utilized oligonucleotide probes to further identify the DR2 specificity and its molecular subtypes on the basis of specific DNA sequences as they occur in a select sample from the Asian Indian population. In addition, oligonucleotide typing of HLA-DQA1 and -DQB1 genes allowed us to determine specific associations of DRB1, DRB5, DQA1, and DQB1 alleles in DR2 individuals. A set of 60 oligonucleotide probes were hybridized to polymerase chain reaction (PCR)-amplified DNA from DR2 homozygous or heterozygous individuals. The most common DR2 subtypes that occurred in this selected population are: DRB1*1501 (60%), DRB1*1502 (33.8%), and DRB1*1602 (6.2%). No example of DRB1*1601 was detected. By combining these results with the allelic variations at DQA1 and DQB1, we were able to detect at least seven different haplotypes, the most common being DRB1*1502-DRB5*0102-DQA1*0103-DQB1*0601 and DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0502. At least five unexpected combinations, not reported among Western Caucasians, were noticed in this sample. Thus oligonucleotide typing is a valuable tool for defining further polymorphisms in the HLA-D region as exemplified by its applications to typing DR2-positive patients with tuberculoid leprosy and pulmonary tuberculosis.

Alleles↗
PubMed1991

Oligonucleotide typing is a perfect tool to identify antigens stimulatory in the mixed lymphocyte culture.

An important criterion for the selection of donors for bone marrow transplantation is the grade of matching for HLA between donor and recipient. For patients that lack an HLA-identical sibling, an extending pool of unrelated volunteers for bone marrow donation is available. From these donors the best matched candidate can be selected by serological typing, followed by a mixed lymphocyte culture (MLC). Oligonucleotide genotyping for HLA class II antigens is considered to be valuable for the prediction of MLC reactivity. We investigated whether this typing method, in combination with serological typing, would cover the recognition of all MLC stimulatory determinants. One hundred thirty-six combinations of HLA-A, -B, and -DR serologically identical individuals were tested in the MLC. Additional typing for HLA-DRB and HLA-DPB by oligonucleotide genotyping made it possible to evaluate the influence of these genes on MLC reactivity. Combinations that were matched for HLA-DRB gave significantly lower responses than those that were mismatched. Nevertheless, in the matched combinations responses were observed to 94% relative response index. These responses could all be attributed to HLA-DP, since all combinations that were identical by HLA-DPB genotyping were negative in the MLC. In conclusion, with the combined use of serology and oligonucleotide genotyping, responder-stimulator combinations can be selected that are identical for all MLC stimulatory determinants.

Bone Marrow Transplantation↗
PubMed1991

Increasing complexity of HLA-DR2 as detected by serology and oligonucleotide typing.

Serological and oligonucleotide typing was performed on a number of HLA-DR2-positive cells from different ethnic origin, including DR2 haplotypes with various DQ associations. Exons 2 of DRB1 and DRB5 of DR2-positive individuals were locus-specific amplified and hybridized with a number of different oligonucleotides capable of discriminating between the various Dw2, Dw12, Dw21, and Dw22 associated sequences. The linkage of DRB with DQA1 and DQB1 in these haplotypes was analyzed. Among the DR2- positive cells we could define 10 different DR DQ haplotypes by serology and 13 by oligonucleotide typing. The DR2.ES specificity is a serological DRw15 variant which could not be discriminated by oligonucleotide typing from a DRw15 DQw5 haplotype. The DR2.JA variant represents a unique DRB1*1602 DRB5*0101 haplotype. The DR1+2s haplotype consists of a DRB1 DQ region from a Dw1 and a DRB5 gene from a Dw2 haplotype. Its short DR2 serum pattern can be explained by the absence of a DR2 DRB1 gene product. DRB5*0101 sequences were found in association with DRB1*1501, *1502, *1602, and *0101 alleles. Since the DRB5 gene is capable of such different associations it is comparable to the DRB3 and DRB4 genes. This may have implications for the definition of the broad DR2 specificity which is predominantly encoded by the DRB5 gene product. New DR2 haplotypes included the following DQ combinations: DQw2-positive DQA1/B1*0301/0201 and DQw6-positive DQA1/B1*0102/0601 and *0102/0603 haplotypes.

Amino Acid Sequence↗
PubMed1990

The nucleotide sequence of the bovine MHC class II alpha genes: DRA, DOA, and DYA.

The nucleotide sequence of the exons 2, 3, and 4, and parts of the intervening sequences of a BoLA-DRA and -DQA gene and one other class II BoLA-A gene have been determined. The structure of the BoLA-DRA and -DQA gene was found to be very similar to that of the corresponding human HLA class II genes. An analysis of the structure of the other class II BoLA-A gene showed that this A gene was clearly very different from both the human A genes and the bovine DRA and DQA genes. The results indicate that this other type of class II A gene probably represents the class II gene that has already been identified in restriction fragment length polymorphism (RFLP) studies as BoLA-DYA. Since no clear homologue of this presumed BoLA-DYA gene was found among the human HLA class II genes, these results indicate that, at least as far as the A genes are concerned, a distinct class II gene is present in cattle.

Amino Acid Sequence↗