Biomedical subjects

J G Kuipers

Publications and source records attributed to J G Kuipers.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Evaluation of amplicor chlamydia PCR and LCX chlamydia LCR to detect Chlamydia trachomatis in synovial fluid.

OBJECTIVES: PCR has been successfully used in research for the detection of C. trachomatis DNA in synovial samples. However, each research laboratory has developed its own PCR, making inter-laboratory comparisons difficult. To allow for standardization we evaluated two commercially available amplification systems originally designed for the examination of urogenital samples (Roche Amplicor Chlamydia PCR and Abbott LCX Chlamydia LCR), using them to analyse spiked and clinical synovial fluid (SF) samples from reactive arthritis (ReA), undifferentiated arthritis (UA), and rheumatoid arthritis (RA) patients. We compared their sensitivity in assays of clinical SF samples with our in-house developed C. trachomatis specific nested PCR. METHODS: SF was spiked with purified C. trachomatis elementary bodies (EB) and analyzed by the commercial assays. Clinical SF samplesfrom ReA (n=21), UA (n=79) and RA (n=50) patients were examined by the two commercial assays and our in-house PCR. RESULTS: Using SF samples spiked with defined numbers of C. trachomatis EB, the sensitivity of the commercial tests was high and similar to published PCR sensitivity. In clinical SF specimens the commercial assays was also able to detect CT; however, the in-house PCR was more sensitive. Out of 10 PCR-positive SF samples Amplicor tested positive in only 4/10 and LCX in only 3/10. The in-house PCR detected chlamydial DNA in synovialfluidfrom 5/21 ReA (24%), 5/79 UA (6%) and in none of the 50 RA patients. CONCLUSION: Commercial amplification assays allow the detection of C. trachomatis in clinical specimens, although with a lower sensitivity than optimized PCR. Potential explanations are discussed.

Adult↗

PubMedDate not supplied

The genetically-engineered secretory B27/Q10 chimeric molecule inhibits HLA-B27 restricted alloreactive T-lymphocytes.

OBJECTIVES: Intracellularly persisting bacterial infections and high association with HLA-B27 are the hallmarks of reactive arthritis. Soluble HLA-B27 molecules are induced by bacterial infection; however their biological role in arthritis is unknown. It was the aim of this study to generate soluble HLA-B27 molecule and to analyze its effect on cytotoxic HLA-B27 alloreactive CD8+ T-lymphocytes in order to better understand potential functional links between persistent infection and HLA-B27 association. METHODS: Using PCR Exons 1 through 4 of HLA-B*2705 were fused to Exon 5 of the soluble murine MHC class I variant Q10 and stably transfected into Hela-cells. Transfectants were analyzed using specific PCR, RT-PCR and intracellular and extracellular staining with anti-HLA-B27 monoclonal antibody ME1. Secretion of B27Q10 in the supernatant was examined by isoelectric focusing (IEF). The effect of B27Q10 on T-cells was analyzed using either HLA-B27- or HLA-A2-restricted alloreactive T-cells in a standard 51Cr-release assay. RESULTS: PCR and RT-PCR demonstrated the DNA and mRNA of B27Q10 in the transfectants. By intracellular and extracellular staining with ME1 B27Q10-molecule was detected intracellularly but was not expressed in the cell membrane. Using IEF soluble B27Q10-molecules were found in supernatants of transfectants in a concentration of up to 1.342 microg/ml. Soluble B27QJO-molecule inhibited specifically the cytotoxicity of HLA-B27-restricted alloreactive T-cells by about 30%. CONCLUSION: The secretory non-membrane-expressed molecule B27Q10 inhibits HLA-B27 specific T-cells. The inhibition of cytotoxic T-cells by bacteria induced soluble HLA-B27 may thus enable bacterial persistence.

Animals↗

PubMedDate not supplied

Anti-tumour necrosis factor (TNF)-alpha therapy in undifferentiated spondyloarthropathy.

The cytokine tumour necrosis factor (TNF)-alpha plays a major role in the spinal inflammatory process of spondyloarthropathy. In contrast to rheumatoid arthritis, disease modifying antirheumatic drugs have not been proved effective against inflammation and progressive ankylosis. Initial studies on TNFalpha inhibitors in ankylosing spondylitis are promising and raise the question as to whether early stages of the disease, mostly classified as "undifferentiated spondyloarthropathy" (uSpA), should also be treated with TNFalpha inhibitors. This article summarises the preliminary results of 11 uSpA patients in 4 different trials treated with TNFalpha inhibitors.

Antibodies, Monoclonal↗

PubMedDate not supplied

Requirements for HLA-B*2705-binding peptides with special regard to the transporter associated with antigen processing (TAP).

OBJECTIVE: To refine the algorithms governing peptide presentation by HLA-B*2705 by analyzing: (i) the specificity of the human transporter associated with antigen processing (TAP) for HLA-B27 binding peptides; and (ii) the peptide binding affinity to HLA-B*2705. METHODS: TAP-translocation was measured with a labeled reporter peptide containing an N-linked glycosylation acceptor site in Streptolysin O-permeabilized cells for a panel of HLA-B27 binding peptides. Peptide binding affinity was determined by peptide-induced stabilization of empty HLA-B*2705 expressed by the TAP-deficient cell line T2-B27. RESULTS: Human TAP preferentially translocated analogues with residues leucine, isoleucine, methionine and arginine as the carboxy-terminal amino acids, whereas analogues with aspartic acid and serine were translocated poorly. The binding affinity to HLA-B*2705 of the poorly translocated aspartic acid and serine analogues was about 100-fold less compared to the parent HLA-B27 binding peptide. CONCLUSIONS: Human TAP shows considerable specificity for the C-terminus of potential HLA-B27 ligands. Nonamer peptides with aspartic acid and serine at the C-terminus are poorly translocated by the TAP and have low binding affinity for HLA-B*2705, and are therefore unlikely to become presented by HLA-B*2705.

ATP-Binding Cassette Transporters↗

PubMedDate not supplied

Evaluation of ELISA to detect Chlamydia trachomatis antigen in urine samples from arthritis patients.

OBJECTIVE: To determine whether examination of urine samples using ELISA allows the detection of asymptomatic C. trachomatis infection in arthritis patients. METHODS: The in vitro sensitivity of IDEIA Chlamydia ELISA to detect C. trachomatis in urine samples was determined by the investigation of serial dilutions of chlamydial elementary bodies. In a clinical study, urine samples from 402 consecutive arthritis patients (182 men and 220 women) in a tertiary care rheumatology clinic were examined for asymptomatic chlamydial infection by ELISA and the results were compared to culture and direct immunofluorescence assay (DFA, MicroTrak) of urogenital swabs. RESULTS: The in vitro sensitivity of ELISA for detecting purified elementary bodies of C. trachomatis serovar K in urine was 60 infection forming units. Twenty-three of 402 arthritis patients (6%) had asymptomatic chlamydial infection as shown by DFA and culture from urogenital smears. The ELISA method identified only 3 of 17 swab-positive patients among 271 patients when urine specimens were collected during the clinical visit, while the assay detected all 6 swab-positive patients among 131 patients when first-voided early morning urine specimens were used (p < 0.001). CONCLUSION: It is mandatory to examine only first voided early morning urine samples if ELISA is used instead of DFA or culture from urogenital swabs to detect asymptomatic chlamydial infection in arthritis patients.

Adolescent↗