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R W Hoffman

Publications and source records attributed to R W Hoffman.

At least 37 records · Page 2Linked to original sources
PubMed1997

Cytokine mRNA expression in the B/W mouse model of systemic lupus erythematosus--analyses of strain, gender, and age effects.

To gain a better understanding of inherent gender-related effects on autoimmunity, cytokine genes were examined in female and male New Zealand Black X New Zealand White (B/W) mice, which are a murine model of systemic lupus erythematosus (SLE). In preliminary studies, semiquantitative reverse transcriptase-polymerase chain reaction analysis showed a trend for B/W spleen cell interferon gamma (IFN-gamma) mRNA in B/W female spleen cells to exceed that of males. This difference was obliterated following concanavalin A (Con A) stimulation. Spleen cells from B/W mice of both sexes were then examined at 6, 18, and 27 weeks of age, and results were compared with matched groups of nonautoimmune DBA/2 mice. Pooled splenocytes from all 12 groups of animals were compared simultaneously for expression of mRNA specific for IFN-gamma, interleukin 4 (IL-4) and interleukin 6 (IL-6). Strain was a potent influence on cytokine transcripts. In unstimulated splenocytes from female and male B/W mice, there was a notable trend for IFN-gamma and IL-6 mRNA expression to exceed transcripts from nonautoimmune DBA/2 mice. When comparisons were carried out by gender, a highly significant increase of IFN-gamma transcripts was apparent in B/W females compared to B/W males at the age of 27 weeks. Following Con A incubation, strain and gender differences were eliminated. IL-4 transcript expression was similar in all pools of cells, and age was not an important factor in expression of any transcript. This study represents the first examination of multiple cytokine transcripts in lymphoid cells from B/W mice. In this hormone-sensitive model of SLE, strain and gender determined in vivo expression of IFN-gamma and IL-6 mRNA.

Age Factors↗
PubMed1997

Mycoplasmas in wild turkeys living in association with domestic fowl.

One hundred and nineteen Merriam's wild turkeys (Meleagris gallopavo merriami) and 31 domestic chickens coexisting on a ranch in west-central Colorado (USA) were surveyed for mycoplasmosis by serologic and cultural methods. Although no clinical signs were apparent in any wild turkeys tested, 51 (43%) had positive rapid plate agglutination (RPA) reactions for M. gallisepticum (MG) and/or M. synoviae (MS); 37% of 56 adults and 48% of 63 subadults were classified as positive reactors to MG and/or MS. No turkeys tested in 1992 (n = 61) and 17 (29%) of 58 turkeys tested in 1993 were RPA-positive for M. meleagridis (MM). Hemagglutination inhibition (HI) test results were negative for MG, MS and MM as were most enzyme-linked immunosorbent assay (ELISA) test reactions (MG = 99%, MS = 93%, MM = 87%). Immunoblotting showed mild to moderate reactivity to MG proteins in 49% of 41 samples tested. Most chickens were strongly positive for MS by RPA (81%), HI (58%) and ELISA (87%); 48% also were positive for MG by RPA but all were MG-negative by HI and ELISA. No pathogenic mycoplasmas were isolated from either group of birds. Mycoplasma gallopavonis was commonly identified from the wild turkeys, and M. gallinaceum was isolated from both the chickens and wild turkeys. In a transmission study conducted in 1994, disease-free domestic turkeys failed to seroconvert when co-housed with wild turkeys from this population that were RPA-positive for MG. Collectively, the results of this study were inconclusive regarding the status of pathogenic mycoplasmas within this wild turkey population.

Agglutination Tests↗
PubMed1997

Antiphospholipid antibodies among anti-U1-70 kDa autoantibody positive patients with mixed connective tissue disease.

OBJECTIVE: The association between antiphospholipid antibodies (aPL) and recurrent venous and/or arterial thrombotic events, fetal loss, and thrombocytopenia in systemic lupus erythematosus (SLE) has been well documented. Such an association has not been carefully assessed in mixed connective tissue disease (MCTD). Our aim was to assess the prevalence and clinical significance of aPL in anti-U1-70 kDa autoantibody positive patients with MCTD. METHODS: We compared 48 consecutive anti-U1-70 kDa autoantibody positive patients with MCTD versus 59 consecutive anti-U1-70 kDa autoantibody negative patients with SLE to determine the frequency of aPL and clinical features of the aPL syndrome. RESULTS: Among the patients with MCTD 7/48 (15%) had anticardiolipin antibodies (aCL) versus 24/59 (41%) patients with SLE (p < 0.005) and versus 2/150 (1%) apparently healthy blood donors (p < 0.001). Among patients with MCTD with aPL, 2 were IgG, 3 IgM, and 2 both IgG and IgM isotypes; among patients with SLE 5 were IgG, 11 IgM, and 8 both IgG and IgM isotypes. No clotting events or other features of the aPL syndrome were found among the patients with MCTD compared with 26 events documented among the group of aCL positive patients with SLE (p < 0.001). There were 10 patients with SLE with deep vein thrombosis, one with a pulmonary embolism, 2 with recurrent fetal loss, one with chorea, 2 with livedo reticularis, one with severe thrombocytopenia, and one with avascular necrosis. CONCLUSION: aCL were increased in patients with MCTD compared to controls. Furthermore, aCL were increased in SLE compared with both patients with MCTD and controls. Finally, while clotting events and other manifestations of the aPL syndrome occurred among the group of aCL positive patients with SLE these were distinctly absent from the aCL positive MCTD group.

Adolescent↗
PubMed1996

T cell receptor V beta usage in murine experimental autoimmune thyroiditis.

Mouse thyroglobulin (MTg)-sensitized spleen cells activated in vitro with MTg induced experimental autoimmune thyroiditis (EAT) in which the thyroid infiltrate consists primarily of mononuclear cells (MNC) (lymphocytic EAT). MTg-sensitized spleen cells cultured with MTg together with anti-IL2R antibody induce a granulomatous form of EAT in which the thyroid is infiltrated by MNC in addition to PMNs, histiocytes, and multinucleated giant cells. CD4+ T cells are the primary effector cells for both forms of EAT. The presence of specific T cell receptor (TCR) V beta families in the thyroid infiltrate was examined by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) amplification of mRNA. At the time of maximal disease severity, cells infiltrating the thyroid expressed primarily V beta 8, V beta 4, V beta 11, and V beta 14 as determined by flow cytometry. RT-PCR confirmed these findings and also detected several additional V beta gene families, including V beta 1, V beta 2, V beta 6, V beta 13, and V beta 15; V beta 3, V beta 10, and V beta 12 were also detected in some, but not all, experiments. There were no differences in the V beta T cell repertoires in thyroids of mice with lymphocytic vs granulomatous EAT. RT-PCR analysis of intrathyroidal MNC 11 days after cell transfer showed TCR V beta mRNA transcripts to be primarily restricted to V beta 4, V beta 11, and V beta 14, whereas the predominant thyroid-infiltrating T cell 21 days after cell transfer was V beta 8+. Depletion of V beta 8+ T cells in recipient mice did not reduce EAT severity. TCR V beta usage shifted predominantly to V beta 4+, V beta 11+, or V beta 14+ T cells of both CD4+ and CD8+ T cell subsets. These results indicate that multiple V beta TCR are expressed in thyroids of mice with EAT.

Animals↗
PubMed1995

Analysis of anti-U1 RNA antibodies in patients with connective tissue disease. Association with HLA and clinical manifestations of disease.

OBJECTIVE: To determine the prevalence of anti-U1 RNA antibodies in connective tissue disease (CTD) patients and evaluate immunogenetic and clinical features of patients possessing these antibodies. METHODS: RNA immunoprecipitation was used to analyze patient and healthy control sera for the presence of anti-R1 RNA antibodies. Enzyme-linked immunosorbent assay and immunoblotting were used to determine small nuclear RNP (snRNP) polypeptide antibodies. HLA polymorphisms were determined by microcytotoxicity and DNA typing. RESULTS: Anti-U1 RNA IgM and IgG antibodies were found in 60% of anti-RNP positive patients. All of the anti-U1 RNA positive patients had anti-70K, and most had anti-A, (U1)snRNP polypeptide antibodies. HLA-DR2/DR4, as well as Raynaud's phenomenon and synovitis, were significantly increased in the anti-U1 RNA positive group. CONCLUSION: The presence of anti-U1 RNA antibodies correlates with anti-70K and anti-A polypeptide antibodies. In addition, the anti-U1 RNA positive CTD patient group is immunogenetically and clinically distinctive from the anti-U1 RNA negative patient group.

Adolescent↗
PubMed1994

Increased frequency of mutations in the hprt gene of T cells isolated from patients with anti-U1-70kD-autoantibody-positive connective tissue disease.

Mixed connective tissue disease (MCTD) is characterized by the presence of high titers of anti-U1-70kD autoantibodies which are the result of substantial B cell activation. The hprt gene encodes the constitutively expressed enzyme hypoxanthine-guanine phosphoribosyl transferase which is active in the purine salvage pathway. Rapidly dividing cells randomly accumulate gene mutations, including mutations in the hprt gene. These mutations may be used to identify activated cells. If activated T cells play a role in the pathogenesis of MCTD, an increased frequency of mutations in the hprt gene might be expected among T cells isolated from such patients. To examine this hypothesis, we isolated and cloned T cells from 10 anti-U1-70kD-autoantibody-positive MCTD patients and determined the precursor frequencies of cells possessing mutations in hprt by comparing the frequency of cells grown in the presence and absence of the purine analogue 6-thioguanine. We found that the frequency of 6-thioguanine-resistant hprt-negative T cells was significantly increased among MCTD patients (mean 566/10(6); range 122-2,845/10(6)) versus age- and sex-matched controls (mean 42/10(6); range 21-78/10(6); p < 0.003). These results demonstrate that there is an increase in the measured mutant frequency of T cells from MCTD patients. Such T cells may play a role in the pathogenesis of this disease.

Adult↗
PubMed1994

Molecular and serologic analysis of HLA genes and immunoglobulin allotypes in IgA nephropathy.

We studied a large North American Caucasian population of patients with biopsy proven IgA nephropathy for polymorphisms of HLA-A,B,C, HLA-DR, HLA-DQ and HLA-DP using a combination of serologic phenotyping and polymerase chain reaction sequence specific oligonucleotide probe (PCR-SSOP) hybridization genotyping. We also examined patients for polymorphisms of immunoglobulin by determining Gm and Km allotypes. When compared to healthy local controls there was an apparent decrease in HLA-DR5 (DRw11, DRw12) suggesting that this allele had a protective effect on disease susceptibility. None of the previously reported HLA-DQ associations found among Japanese or british Caucasian patients were found among this large North American Caucasian population. The HLA-DPB1*0601 genotype was increased among patients, but this was not significant when corrected for multiple comparisons. There were no differences in the distribution of Gm or Km allotypes among patients versus controls, regardless of whether they were stratified into those with progressive or non-progressive renal disease. Taken together, these findings suggest that there is substantial genetics heterogeneity in susceptibility to IgA nephropathy among different ethnic and/or geographically distinct populations.

Alleles↗
PubMed1993

Human T cell clones reactive against U-small nuclear ribonucleoprotein autoantigens from connective tissue disease patients and healthy individuals.

SLE and mixed connective tissue disease (MCTD) are characterized by the presence of high titers of autoantibodies against uridine-rich RNA-small nuclear ribonucleoprotein (snRNP) Ag. Because the presence of such snRNP-reactive autoantibodies has recently been shown to be associated with polymorphisms of HLA, this study was undertaken to determine whether snRNP-reactive T cells could be identified and characterized from patients. PBMC were stimulated with affinity-purified snRNP Ag and cloned by limiting dilution in the presence of rIL-2 and rIL-4, snRNP-reactive human T cell clones were generated from three patients and two healthy blood donors who possessed disease-associated HLA genotypes. The cell surface phenotype of clones determined by flow cytometry was CD3+, CD4+, CD45RO+, TCR V alpha beta+. TCR V beta analysis, performed using V beta-specific primers and polymerase chain reaction, revealed that the T cell lines generated were clonal; a limited number of TCR V beta genes were expressed among the clones tested. All clones tested by mAb blocking of Ag-induced proliferation were restricted by HLA-DR. Several T cell clones were identified that were specific for B'/B or D polypeptides. These results demonstrate that snRNP-reactive T cells can be isolated from SLE and MCTD patients in vitro, and that Ag-driven expansion of such T cells could play a role in the immunopathogenesis of these diseases in vivo.

Adult↗
PubMed1993

U1-70-kd autoantibody-positive mixed connective tissue disease in children. A longitudinal clinical and serologic analysis.

OBJECTIVE: To obtain longitudinal data on the clinical, serologic, and immunogenetic features of children with mixed connective tissue disease (MCTD). METHODS: Eleven children with MCTD were followed up for a mean of 9.8 years. Enzyme-linked immunosorbent assay and immunoblotting were used to analyze sera for autoantibodies to small nuclear ribonucleoprotein polypeptides. HLA types were determined in 9 patients, by microcytotoxicity and DNA typing. RESULTS: All 11 children had anti-U1-70-kd auto-antibodies. Six of 9 were positive for HLA-DR2, 4 of 9 for HLA-DR4, and 9 of 9 for either HLA-DR2 or DR4. Outcomes were favorable with no functional impairment in 8 of the 11 children and were poor in 3. CONCLUSION: The frequency of HLA-DR2/DR4 is increased among children with anti-U1-70-kd autoantibody positive MCTD.

Autoantibodies↗
PubMed1992

Molecular genetic analysis of HLA-DR and HLA-DQ genes among anti-U1-70-kd autoantibody positive connective tissue disease patients.

OBJECTIVE: We have recently found that the presence of autoantibodies against the 70-kd polypeptide of U1 RNP (U1-70-kd) is associated with HLA-DR4 and DR2. To further characterize this association, we performed a molecular genetic analysis of HLA-DR and DQ genes among patients with autoantibodies against U1-70-kd. METHODS: The polymerase chain reaction (PCR), sequence-specific oligonucleotide hybridization, and solid-phase direct DNA sequencing of PCR-amplified DNA were utilized to analyze HLA-DRB1, DRB5, DQA1, and DQB1 genes. RESULTS: A comprehensive analysis of HLA-DRB1, DRB5, DQA1, and DQB1 from 27 patients and controls identified shared amino acids FDYFYQA (Phe, Asp, Tyr, Phe, Tyr, Gln, Ala) at positions 26, 28, 30-32, 70, and 73 of HLA-DRB1 on disease-associated haplotypes. CONCLUSION: A common cluster of shared amino acids, or a shared epitope, identified within HLA-DRB1 among anti-U1-70-kd autoantibody positive connective tissue disease patients may be important in regulating an autoimmune response to the U1-70-kd antigen.

Amino Acid Sequence↗
PubMed1991

Association of immunoglobulin Km and Gm allotypes with specific antinuclear antibodies and disease susceptibility among connective tissue disease patients.

The distribution of the immunoglobulin Km(1) and Gm phenotypes was examined in patients with connective tissue diseases, including systemic lupus erythematosus, mixed connective tissue disease, and scleroderma, whose sera were characterized for antibodies against nuclear antigens and polypeptides of U small nuclear ribonucleoproteins. We found a strong association between Km(1) phenotype and susceptibility to systemic lupus erythematosus (P less than 0.00001, relative risk = 17). We also found a positive association between the Km(1) phenotype and the presence of anti-double-stranded DNA antibodies. The presence of certain immunoglobulin genes or gene families may have a role in susceptibility to the development of autoantibodies and/or of connective tissue disease.

Antibodies, Antinuclear↗
PubMed1991

Solid-phase direct DNA sequencing of allele-specific polymerase chain reaction-amplified HLA-DR genes.

We describe in this report a new strategy to directly sequence polymerase chain reaction-amplified human leucocyte antigen DRB genes using biotinylated allele-specific synthetic oligonucleotide primers coupled to streptavidin-coated magnetic beads. The use of allele-specific primers in the polymerase chain reaction allows for selective amplification of DNA from one haplotype, which when combined with the direct sequencing technique circumvents the need for DNA cloning prior to sequencing. We demonstrate here that this method can be used to characterize human leucocyte antigen DRB genes among heterozygous individuals. This method can be used for the rapid analysis of highly polymorphic genes among individuals heterozygous at the gene of interest.

Alleles↗
PubMed1990

Human autoantibodies against the 70-kd polypeptide of U1 small nuclear RNP are associated with HLA-DR4 among connective tissue disease patients.

Serum samples from patients with connective tissue disease (CTD) were characterized using a recently developed enzyme-linked immunosorbent assay for reactivity with individual specific polypeptides of U1 small nuclear ribonucleoproteins, including the U1-70-kd protein. The distribution of HLA antigens was compared in CTD patients with and in those without anti-U1-70-kd autoantibodies and in normal controls. The frequencies of HLA-DR4 and HLA-DRw53 were increased among the anti-U1-70-kd autoantibody positive CTD group compared with the frequencies in anti-U1-70-kd autoantibody negative systemic lupus erythematosus patients and compared with normal controls. We conclude that the presence of autoantibodies reactive with the anti-U1-70-kd protein antigen is associated with HLA-DR4 and HLA-DRw53.

Antibodies, Antinuclear↗