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Biomedical subjects

H H Peter

Publications and source records attributed to H H Peter.

At least 145 records · Page 8Linked to original sources

Precursor frequencies for DNA-specific B lymphocytes in patients with systemic lupus erythematosus (SLE).

Precursor frequencies for anti-DNA-secreting B cells were estimated in six healthy donors and 18 SLE patients with active and inactive disease. Precursors for IgG anti-dsDNA-secreting B cells were exclusively detected in SLE patients (73% of active patients and one inactive patient, 0.01-0.99% of IgG-producing B cells). These frequencies were in the same order of magnitude as frequencies of precursors for IgG anti-tetanus toxoid, which were detectable in three healthy volunteers after booster vaccination (0.07-0.8% of IgG-producing B cells), but not before (< 0.01%). Precursors for IgG anti-ss-DNA secreting B cells were observed in 33% of healthy donors and in 78% of SLE patients (0.01-0.32% of IgG-producing B cells). Only patient-derived IgG anti-DNA clones cross-reacted with (33%) or were monoreactive to dsDNA (12%). Precursors for IgM anti-DNA-secreting B cells were observed in healthy donors and SLE patients in comparable frequencies and with similar reactivities with ssDNA and dsDNA. Segregation analyses and sorting experiments showed that > 94% of clones secreting IgG anti-DNA were derived from in vivo sIgG+ B cells. sIgM+ B cells were induced to switch in vitro; however, only twice were cultures containing IgM and IgG anti-DNA antibodies observed under clonal conditions. In conclusion, our results indicate that precursor B cells for IgG anti-dsDNA in SLE patients are similarly selected and expanded as are precursor B cells specific for foreign antigens such as tetanus toxoid.

Adult↗

Impaired granulocyte oxidative burst and decreased expression of leucocyte adhesion molecule-1 (LAM-1) in patients with Wegener's granulomatosis.

Neutrophils are the target of autoantibodies in Wegener's granulomatosis (WG). In this study, granulocyte function and surface marker expression were investigated in patients with WG. The oxidative burst in response to phorbol myristate acetate (PMA) was tested with granulocytes of 25 patients with histologically proven WG. A significantly diminished percentage of oxygen radical-producing cells was found in patients with active disease. Surface antigen expression of CD11b and LAM-1 was analysed on granulocytes of 20 patients with WG. Whereas the expression of CD11b was normal, surface expression of LAM-1 was decreased in nine cases with WG. The decrease of LAM-1 correlated with disease activity. Phagocytosis of Escherichia coli was tested in 10 patients with WG, and normal values were found in all cases. We conclude that down-regulation of LAM-1 may be a marker of disease activity in WG. The altered response to PMA may indicate functional changes in granulocyte reactivity due to autoantibody-induced damage of the granulocyte membrane.

Cell Adhesion Molecules↗

Intestinal B cell defects in common variable immunodeficiency.

The humoral immune system of the small intestine of 17 patients with common variable immunodeficiency (CVID) was studied by immunohistology using antibodies specific for IgA1,2, IgM, IgG1-4, the J chain and the secretory component (SC). IgA1,2+, IgG2+ and IgM+ lamina propria B cells were totally lacking in 65% (11/17), 41% (7/17) and 18% (3/17) of CVID patients, respectively. One patient exhibited an isolated IgA1 subclass deficiency. The proportion of plasma cells in conventionally stained histological sections of the same intestinal biopsies showed a close correlation with the numbers of IgA+ and IgM+ cells. Considerable numbers of J chain-synthesizing cells were present in all patients with CVID, indicating the presence of early B cells unable to differentiate into immunoglobulin-producing plasma cells. Most of the patients with intestinal IgA and/or IgM defects strongly expressed the SC in their enterocytes, suggesting an immunoglobulin-independent regulation of the SC. Clinically, only CVID patients with intestinal IgA defects developed intestinal infections with Giardia lamblia, Campylobacter jejuni or Candida albicans. The outcome of in vitro immunoglobulin synthesis assays with peripheral blood lymphocytes did not predict the presence or absence of the respective isotype-producing B cells in the intestinal lamina propria. Thus, immunohistological examinations of intestinal biopsies are required to determine the extent of mucosal immunodeficiency in CVID patients.

Adolescent↗

Characterization of an HLA-DR4-restricted T cell clone recognizing a protein moiety of small nuclear ribonucleoproteins (UsnRNP).

In sera of patients with mixed connective tissue disease (MCTD, Sharp Syndrome) high titres of IgG autoantibodies to U1snRNP-specific proteins are found. The isolated occurrence of these autoantibodies is highly associated with the HLA-DR4 haplotype. snRNP-specific T cells are supposed to be involved in this autoantibody production. To address this question we cultured mononuclear cells from MCTD patients and healthy donors with a highly purified UsnRNP preparation from HeLa cells using bulk or limiting dilution cultures. Secondary responses to snRNP were detected only rarely with T cell lines from two patients and two controls, and turned out to be unstable during further expansion. One T cell line derived from a healthy individual retained its snRNP reactivity upon limiting dilution cloning and could be characterized in detail. The CD4+ T cell clone recognized native snRNP particles presented by monocytes in an HLA-DR4 (B1*0401)-restricted manner. Separation of the protein and RNA moieties of snRNP particles revealed that the T cell clone responded specifically to the protein fraction, but not to RNA and diverse control antigens. Sequencing of the T cell receptor alpha and beta chain cDNAs revealed that the clone used the V alpha 14.2 and V beta 14 elements. Upon antigen-specific and mitogenic stimulation the T cell clone showed a Th1-specific cytokine pattern, and did not provide helper activity for in vitro immunoglobulin production. This study demonstrate the presence of self-reactive snRNP-specific T cells in a healthy donor. The T cell clone may not represent a helper T cell for the formation of U1snRNP-specific autoantibodies.

Amino Acid Sequence↗

Radiographic course of pulmonary manifestations in Wegener's granulomatosis under immunosuppressive therapy.

Eleven patients with generalized Wegener's granulomatosis were studied. Pulmonary involvement occurred 1 month earlier than a rapid rise of serum creatinine value. Under immunosuppressive therapy, nodules and infiltrations abated slower in patients with bronchopulmonary superinfection (mean, 30 days) compared with patients without superinfection (mean, 18 days). In the short run, radiographic course was a better indicator for therapeutic success than the course of cytoplasmatic antineutrophil cytoplasm antibody titer. If the pulmonary findings did not begin to clear within 1 week after treatment had been started, either superinfection or insufficient immunosuppression was present. In this situation, a more aggressive therapy in combination with antibiotics is suggested.

Adult↗

Production of cladospirone bisepoxide, a new fungal metabolite.

Cladospirone bisepoxide (1), a novel metabolite, was isolated from cultures of a fungus which was characterized as a coelomycete by the formation of pycnidia. By optimization of media and fermentation conditions, a titer of up to 1.5 g/liter on shake level and 1.16 g/liter on bioreactor scale could be achieved. The isolation of the compound was performed by solvent extraction of the culture broth and subsequent crystallization. Cladospirone bisepoxide displays selective antibiotic activity against several bacteria and fungi and inhibits germinations of Lepidium sativum at low concentrations.

Anti-Bacterial Agents↗

3-Alkanoyl-5-hydroxymethyl tetronic acid homologues and resistomycin: new inhibitors of HIV-1 protease. I. Fermentation, isolation and biological activity.

In the course of a screening program for HIV-1 protease inhibiting activity, six new homologues of 3-alkanoyl-5-hydroxymethyl tetronic acids (1 approximately 6) and the known natural product resistomycin (7) were isolated from cultures of the Actinomycete strain DSM 7357. The substituted tetronic acids belong to a recently described structural class of secondary metabolites. The HIV-1 activity of resistomycin (7) has not been reported before.

Actinomycetaceae↗

[Immunohistochemical characterization of the intestinal immune system of patients with AIDS].

Lamina propria mononuclear cells in duodenal and colonic biopsies of AIDS patients and controls were immunohistologically studied for T-cells (CD3), IgA1+, IgA2+, IgM+, IgG2+, IgG4+ and J-chain-positive cells. In AIDS patients, there was a decrease of IgA1+ (p = 0.0009), IgA2+ (p = 0.011), IgM+ (p = 0.018), IgG4+ (p = 0.0002) cells in the duodenum. In the colonic biopsies, IgA2+ (p = 0.0001) and IgG2+ (p = 0.0372) cells were also decreased, whereas the IgM+ cells were increased (p = 0.0023). Relative numbers of J-chain-expressing cells of the small and large intestine were not different from controls (p = 0.373; p = 0.0618). The number of T-cells was reduced in duodenal and colonic biopsies (p = 0.0002; p = 0.0030). The presented results are compatible with the assumption of a functional B-cell defect of the intestinal immune system. The decrease of Ig-producing cells in the intestine contrasts with the increased levels of serum Ig in AIDS patients, indicating that the GALT is a particular compartment of the immune system.

Acquired Immunodeficiency Syndrome↗

[Differential diagnostic aspects of lethal midline granulomas (granuloma gangraenescens].

The lethal midline granuloma and limited Wegener's granulomatosis show clinical similarity, although they are of different etiology. The following case of a 53-year-old woman shows how difficult it is to establish the precise diagnosis of lethal midline granuloma. The diagnosis depends on the pathological finding of a lymphoma. The lymphoma can be differentiated in a T- or a B-cell lymphoma by immunostaining. However, the diagnostic yield of biopsies from the nose is not perfect. It would be, therefore, important to find other diagnostic criteria. The presence of the c-ANCA is a helpful tool, but in the case of limited Wegener's granulomatosis, it has a sensitivity of 50%. The prognosis of the lethal midline granuloma is poor even if an adequate radiation therapy is instituted.

Diagnosis, Differential↗

[Cold labile serum and plasma proteins: clinical and diagnostic significance of cryoglobulins, cryofibrinogen and cold agglutinins].

Cold labile serum and plasma proteins can cause a variety of clinicopathological symptoms. Due to altered physicochemical properties, cryoglobulins and cryofibrinogens may cause increased serum viscosity, cold dependent protein precipitation or, in rare cases, serum gelification. Cold agglutinins, on the other hand, cause temperature dependent agglutination of erythrocytes and eventually hemolysis. All pathological cold dependent serum and plasma phenomena are associated with either neoplasma, autoimmune disorders, various infections or are considered as "essential". While the diagnosis of these conditions remained largely unchanged during the last 10 years, new aspects regarding etiology, pathogenesis, and therapy have arisen.

Agglutinins↗

A comparative study of the iron-clearing properties of desferrithiocin analogues with desferrioxamine B in a Cebus monkey model.

A comparative study of the iron-clearing properties of subcutaneously administered desferrioxamine B (DFO) with those of orally administered desferrithiocin sodium salt (1), desmethyl desferrithiocin (2), desazadesmethyl desferrithiocin sodium salt (3), desazadesmethyl desferrithiocin pivaloyloxymethyl ester (4), and desazadesmethyl-5,5-dimethyl desferrithiocin (5) in an iron-loaded Cebus monkey model and a non-iron overloaded bile duct-cannulated rat model is presented. All six drugs, which performed well in rodent studies, demonstrated increased efficiency in the Cebus monkey model. When administered to rodents at a daily dosage of 384 mumol/kg over a period of 10 days, drug 1 demonstrated severe renal toxicity. whereas drugs 3, 4, and 5 exhibited severe gastrointestinal (GI) toxicity. Under the same experimental protocol, drug 2 did not show significant toxic side effects. In addition, to further evaluate the iron-clearing properties of analogue 2, a dose-response study was performed in the primates that showed that iron excretion increased in a dose-dependent fashion.

Animals↗

Susceptibility to relapsing polychondritis is associated with HLA-DR4.

OBJECTIVE: To determine the frequency of HLA class II antigens in Caucasian central European patients with relapsing polychondritis (RP). METHODS: HLA class I, DR, and DQ specificities were identified in 41 patients with RP, and the frequencies were compared with those in 204 healthy, unrelated control subjects. HLA typing was performed using the standard complement-dependent microcytotoxicity assay. HLA-DR genotyping of 12 DR4-positive RP patients and 57 controls was performed by allele-specific oligonucleotide probing after amplification of genomic DNA by polymerase chain reaction. RESULTS: A significant increase in DR4 antigen frequency was found in the patients (56.1%) as compared with that in healthy controls (25.5%) (Pcorr < 0.001). Genotyping of DR4-positive patients and controls revealed no predominance of any DR4 subtype. CONCLUSION: There are important clinical similarities and overlaps between RP and rheumatoid arthritis (RA). In RA, the association with DR4 has been well established. Our findings show that although there is a DR4 association with RP, the situation is sufficiently distinct from that of RA to imply considerable differences in pathogenesis of the two conditions.

Alleles↗

Increased expression of CD25 and adhesion molecules on peripheral blood lymphocytes of patients with Wegener's granulomatosis (WG) and ANCA positive vasculitides.

Peripheral blood lymphocytes of 29 c-ANCA positive WG patients fulfilling the ACR classification criteria were examined for the expression of various leukocyte surface molecules by dual marker cytofluorometry (FACStar, Becton Dickinson). Activation markers such as CD25, HLA-DR, CD29 and adhesion molecules (ICAM-1 and LFA-3) were clearly elevated in this group in comparison to 40 healthy volunteers. Similar results were obtained for p-ANCA positives vasculitides (n = 13) and, unexpectedly, also for patients suffering from cholesteatoma, a chronic, bacterial infection of the middle ear (n = 21). The results are discussed in view of a pathogenic model for WG and vasculitic disorders.

Adult↗

p-ANCA of undefined specificity in ulcerative colitis: correlation to disease activity and therapy.

Sera of 108 patients with chronic inflammatory bowel disease (IBD) and 13 sera from patients with other gastrointestinal diseases were screened for antibodies against neutrophil cytoplasmic antigens (ANCA) by an indirect immunofluorescence test. 37 out of 64 sera (58%) from patients with ulcerative colitis (UC) produced a fine granular and perinuclear ANCA staining pattern ("snowdrift-like" p-ANCA) clearly different from the cytoplasmic ANCA fluorescence (c-ANCA) seen in active Wegener's granulomatosis (WG) and the typical p-ANCA pattern produced by anti-myeloperoxidase (MPO) autoantibodies. Only 1 of 44 sera from patients with Crohn's disease (CD) and none of the control sera showed positive "snowdrift-like" p- ANCA reactions. 31 out of the 37 p-ANCA positive sera (84%) were obtained from patients with high disease activity with and without longterm high dose steroids. p-ANCA titers became negative after longterm steroid therapy and following complete colectomy.

Adult↗

A long-term longitudinal isotypic study of anti-topoisomerase I autoantibodies.

In this first retrospective longitudinal study of anti-topoisomerase I autoantibodies (anti-topo I) we examined the isotypic expression in 13 patients with scleroderma by enzyme-linked immunosorbent assay. Titers were stable for up to 16 years. However, one patient lost the antibody, while another developed high levels of IgM with myositis and another, high levels of IgA with cardiac disease. For the first time the de novo development of anti-topo I was observed.

Adult↗