Comparison of diagnostic performance of cardiac troponin I on the IMMULITE system with other automated troponin I assays in minor myocardial damage.

An analytical and clinical evaluation of cardiac troponin I (cTnI) on the IMMULITE system is presented. The assay results were compared with those of the Stratus II and the Dimension RxL-HM. A between-run imprecision CV < 20% was found at a cTnI concentration of 0.23 microg/L (functional limit of detection). On the basis of a reference study including 215 patients without ischemic heart disease (97.5th percentile: 0.294 microg/L) and 36 patients clinically classified as having stable angina pectoris (<0.22 microg/L) a preliminary cutoff level of 0.3 microg/L was defined. Assay linearity, sample stability, influence of sample material and method comparison studies were performed. In patients with Duchenne's disease, chronic hemodialysis treatment, pulmonary embolism, coronary artery bypass surgery and minimally cardiac surgery the cTnI results of the IMMULITE agreed better with the Dimension RxL-HM than with the Stratus II data. Of 142 samples from patients with unstable angina 67 samples were classified as cTnI positive with the IMMULITE, 76 with the Dimension RxL-HM, and 62 with the Stratus II. In conclusion, the new assay is sensitive for the determination of cTnI and easy to perform within 45 min.

Analytical and clinical evaluation of troponin I determination on dimension RXL-HM.

The evaluation of cardiac troponin I (cTnI) on the Dimension RxL-HM analyzer is presented. The one-step enzyme immunoassay is based on two cTnI specific monoclonal antibodies. Performed on a separate module of the analyzer, assay-time is 17 minutes. Using as criterion a between-run impression CV <20% the functional limit of detection was set at 0.1 microg/l. Cutoff level for minor myocardial damage of 0.1 microg/l was found. In Duchenne's dystrophy, patients showed increased cardiac Troponin T (cTnT) but no increased cTnI. In patients with a history of coronary heart disease undergoing chronic hemodialysis, cTnT and cTnI were increased. In different patients with submassive pulmonary embolism, increased cTnI was determined. In coronary artery bypass surgery without perioperative myocardial infarction, patients with extracorporeal circulation showed significantly higher cTnI at 24 h after surgery than those with minimal cardiac surgery. In patients with unstable angina, increased cTnI was found more often than on Stratus analyzer. In conclusion, the new assay is a very sensitive cTnI assay, fast and easy to perform in parallel to enzyme and substrate assays.

[New aspects in the pathogenesis of Bechterew disease]. / Neue Aspekte zur Pathogenese des Morbus Bechterew.

The association of HLA-B27 with ankylosing spondylitis (AS), first described more than 20 years ago, triggered intensive research all over the world. AS is a disease model to study the interplay between genetic, immunologic, and environmental factors in the induction of rheumatic disease. Over the past years, substantial advances have taken place in the area of the molecular and cellular immunology of the HLA-B27 molecule, HLA-B27 subtype polymorphism, peptide binding and presentation to cytotoxic T cells, and their relevance to disease. New insights into the pathogenesis of the spondylarthropathies come from the development of animal models, namely HLA-B27/human beta 2-microglobulin transgenic rats, and HLA-B27 transgenic, beta 2-microglobulin knock-out mice. The role of gram-negative bacteria and gut inflammation in the development of ankylosing spondylitis continues to be the focus of interest in many studies. In this review, recent hypotheses of the pathogenesis of AS and its relationship to HLA-B27 are discussed.

Klebsiella pneumoniae-reactive T cells in blood and synovial fluid of patients with ankylosing spondylitis. Comparison with HLA-B27+ healthy control subjects in a limiting dilution study and determination of the specificity of synovial fluid T cell clones.

OBJECTIVE: To study the frequency of Klebsiella pneumoniae-responsive T cells in the peripheral blood (PB) of ankylosing spondylitis (AS) patients compared with that in healthy HLA-B27+ donors, and to examine T lymphocyte clones (TLC) derived from AS patient synovial fluid (SF) for the presence of Klebsiella reactivity. METHODS: Limiting dilution analysis of PB T cells in 8 patients with active AS and in 8 HLA-B27+ healthy subjects was used to determine the frequency of PB T cells responsive to K pneumoniae and Escherichia coli GroEL. SF T cells from a patient with active AS were cloned, and 125 TLC were characterized in proliferation assays. RESULTS: There were fewer T cells in the PB of AS patients that reacted with K pneumoniae than in the PB of healthy HLA-B27+ subjects. The frequencies of E coli GroEL-responsive T cells were approximately 5-10 times lower in all subjects tested (healthy donors and AS patients), but without significant differences between the 2 groups. Two CD4+ TLC that recognized K pneumoniae (1 cross-reactive with E coli) as well as 3 TLC that recognized GroEL (2 CD4+, 1 T cell receptor gamma/delta+) were isolated from the SF of a patient with actige AS. CONCLUSION: Our results indicate that there is a quantitative reduction of K pneumoniae-responsive T cells in the PB of AS patients as compared with healthy controls. This may reflect a defective peripheral T cell defense in the immune response to Klebsiella and may allow bacterial antigens to reach the synovium, where they initiate specific T cell responses.