Rudolf Mierau

Frequency of disease-associated and other nuclear autoantibodies in patients of the German network for systemic scleroderma: correlation with characteristic clinical features

IntroductionIn the present study, we analysed in detail nuclear autoantibodies and their associations in systemic sclerosis (SSc) patients included in the German Network for Systemic Scleroderma Registry.MethodsSera of 863 patients were analysed according to a standardised protocol including immunofluorescence, immunoprecipitation, line immunoassay and immunodiffusion.ResultsAntinuclear antibodies (ANA) were detected in 94.2% of patients. In 81.6%, at least one of the autoantibodies highly associated with SSc or with overlap syndromes with scleroderma features was detected, that is, anti-centromere (35.9%) or anti-topoisomerase I (30.1%), followed in markedly lower frequency by antibodies to PM-Scl (4.9%), U1-ribonucleoprotein (U1-RNP) (4.8%), RNA polymerases (RNAPs) (3.8%), fibrillarin (1.4%), Ku (1.2%), aminoacyl-transfer RNA synthetases (0.5%), To (0.2%) and U11-RNP (0.1%). We found that the simultaneous presence of SSc-associated autoantibodies was rare (1.6%). Furthermore, additional autoantibodies were detected in 55.4% of the patients with SSc, of which anti-Ro/anti-La, anti-mitochondrial and anti-p25/p23 antibodies were most frequent. The coexistence of SSc-associated and other autoantibodies was common (43% of patients). SSc-associated autoantibodies disclosed characteristic associations with clinical features of patients, some of which were previously not acknowledged.ConclusionsThis study shows that five autoantigens (that is, centromere, topoisomerase I, PM-Scl, U1-RNP and RNAP) detected more than 95% of the known SSc-associated antibody responses in ANA-positive SSc patients and characterise around 79% of all SSc patients in a central European cohort. These data confirm and extend previous data underlining the central role of the determination of ANAs in defining the diagnosis, subset allocation and prognosis of SSc patients.

Intraspecies transfer via total cellular DNA of the gene for hypoxanthine phosphoribosyltransferase into cultured mouse cells

SummaryUnder selective growth conditions a revertant of mouse cells, defective in hypoxanthine phosphoribosyltransferase activity (HPRT, EC-No. 2.4.2.8), was isolated, which contained an electrophoretically abnormal form of HPRT activity. The specific HPRT activity in crude extracts of the revertant cells is about 30% of the level determined in normal wild type cells. The variant HPRT reacts with antiserum against normal mouse HPRT but the rate of heat inactivation of the variant activity is different from the wild type form. By isozyme and karyotype analyses of somatic cell hybrids between the revertant mouse cells and Chinese hamster cells we found that the abnormal HPRT activity is coded for by the mouse X-chromosome as expected for a mutation in the structural HPRT gene.DNA has been purified from the abnormal HPRT revertant cells and incubated with mouse A9 cells (HPRT-). After growth in selective medium one clone was isolated which expressed the electrophoretically abnormal form of HPRT. Six clones showed the normal form of HPRT due to reversion of the defective HRRT locus in A9 cells. This result indicates DNA-mediated transfer of the mouse HPRT gene at a frequency of about 0.5×10-7. A similar frequency has been found for transfer of the variant HPRT locus via isolated metaphase chromosomes to A9 recipient cells. When placed in non-selective media the DNA-mediated transferent cells gradually lost their ability to express the HPRT transgenome at a rate of about 6% per average cell generation.

Diagnosis and prognosis of early rheumatoid arthritis, with special emphasis on laboratory analysis

Abstract Diagnosis of rheumatoid arthritis (RA) is mainly based on clinical criteria of symmetric polyarthritis of the hands and feet, with morning stiffness lasting usually more than 1h. Autoantibodies typical for RA, i.e., rheumatoid factors and anti-cyclic citrullinated peptide, and measurements of inflammation add more specific information, especially for early diagnosis, where clinical presentation may be oligosymptomatic involving only a few joints. These laboratory parameters are also relevant for prognosis of disease persistence, functional impairment and radiological progression.

Antigenic determinants shared between HLA-A, -B, -C antigens and H-2 class I molecules modified by bovine beta-2 microglobulin

The specificity of the mouse class I-specific antibody COB6-3 was examined in detail. It was found to react with the mouse class I molecules H-2Db, Kd, and Qa-2, and with human HLA-A, −B, −C antigens. The specificity pattern of COB6-3, despite its different origin, was similar to that of the monomorphic HLA class I-specific antibody W6/32. Cross-inhibition studies show that on human cells the antigenic determinants recognized by the two antibodies are situated close together and may be identical. On mouse cells, reactivity of both antibodies was generated upon replacement of mouse beta-2 microglobulin (B2m) with its bovine counterpart, but differences in specificity were observed using human B2m.

Chromosomal gene transfer of human cytosol thymidine kinase into mouse cells

SummaryIf a chromosomal fragment transferred into recipient cells were integrated or strongly associated with a specific recipient chromosome it should segregate with this chromosome in hybrid cells. In order to corroborate this prediction we studied two independent mouse cell clones (“transferent clones”) which had taken up by chromosomal gene transfer a human chromosomal fragment carrying the gene for cytosol thymidine kinase (TKs, E.C.No.2.7.1.75). The following results were obtained.1.Ten somatic cell hybrids isolated after fusion of transferent mouse clones and chinese hamster cells expressed functional human TKs and mouse galactokinase (GALK, E.C.No.2.7.1.6) activity. Counterselected derivatives of all clones had lost human TKs but still expressed mouse GALK. Recently both mouse genes for TKs and GALK have been assigned to mouse chromosome 11 (Kozak and Ruddle, 1977a, McBreen et al., 1977). Therefore our results argue against integration or association of the human gene for TKs at the site of the homologous defective mouse TKs-GALK-region in the genome of transferent clones.2.In three somatic cell hybrids isolated after fusion of microcells from two different transferent mouse clones with established chinese hamster cells only human TKs but not mouse GALK was expressed. Karyotypic analysis of one hybrid suggested the presence of at least one copy of mouse chromosome 9 per hybrid cell. Chromosome 9 and the mouse isozyme activity of mannose phosphate isomerase which had been previously assigned to a gene locus on mouse chromosome 9 were missing in a subclone counter-selected against the presence of TKs activity. These findings suggested that the transferred human gene for TKs may be integrated or strongly associated with mouse chromosome 9 in this transferent mouse clone.3.Two other somatic cell hybrids were analyzed which were derived from a different phenotypically stable transferent mouse clone by similar microcell fusion with the chinese hamster cells. Although these hybrids expressed human TKs activity, no mouse chromosome could be detected in these clones. Possibly after fusion of microcells derived from certain transferent mouse clones the transferred human chromosomal fragment could become translocated from a mouse chromosome to the chinese hamster genome.

Diagnostik und Prognostik der frühen rheumatoiden Arthritis unter besonderer Berücksichtigung der Labor-Analytik Diagnosis and prognosis of early rheumatoid arthritis, with special emphasis on laboratory analysis

Zusammenfassung Ausgehend vom klinischen Befund einer Arthritis von zwei oder mehr Gelenken wird die Diagnose einer rheumatoiden Arthritis (RA) überwiegend nach klinischen kriterien gestellt; auch die Labordiagnostik trägt jedoch wesentlich zur Frühdiagnostik der RA bei, zum einen durch die Entzündungsdiagnostik, zum anderen durch den Nachweis der RA-typischen Autoantikörper Rheumafaktor und anti-CCP. Die genannten Laborparameter haben, neben anderen Kriterien, zusätzlich zur diagnostischen auch prognostische Bedeutung im Hinblick auf Persistenz der Erkrankung, funktionelle Einbußen und radiologische Progression.

A Monoclonal Antibody Induced by H-2 Syngeneic ConA Blasts: Its Reactivity Pattern with Mouse and Human MHC Class I Antigens

Class I antigens encoded by the major histocompatibility complex (MHC) are notable for their high level of interspecies homology. The monoclonal antibody COB6-3 highlights some aspects of this feature. The antibody’s production, characterization, and specificity are reviewed and summarized in this article.