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Biomedical subjects

L R Wedderburn

Publications and source records attributed to L R Wedderburn.

At least 19 recordsLinked to original sources
PubMed2006

The Juvenile Dermatomyositis National Registry and Repository (UK and Ireland)--clinical characteristics of children recruited within the first 5 yr.

OBJECTIVES: To identify epidemiological, clinical and laboratory characteristics of juvenile dermatomyositis (JDM) in a national multi-centre cohort of patients, and to review recent changes in the understanding of management and prognosis in the light of these data. METHODS: All children with idiopathic inflammatory myositis recruited to the Juvenile Dermatomyositis National Registry and Repository (UK and Ireland) were included. Features at presentation, and later in disease, were assessed and evaluated. A total of 63 out of 175 children with a new diagnosis of myositis were recruited at the time of diagnosis and followed prospectively. Out of the 175 children, 122 diagnosed prior to 2000 were recruited retrospectively, with subsequent data collected prospectively. RESULTS: One patient died (0.7%), which is equivalent to one death per 465 patient years. Data were available at the time of analysis on 151 registered patients. The most common presenting features were characteristic rash, weakness, tiredness, Gottron's patches and myalgia. Muscle biopsy, magnetic resonance imaging and muscle enzymes were frequently, but not always, abnormal. Muscle enzymes and erythrocyte sedimentation rate were not useful markers of disease activity. CONCLUSIONS: The JDM National Registry and Repository captures data on a significant cohort of children with inflammatory myositis. The current study reports the largest European cohort of children with dermatomyositis to date. This powerful resource will help improve our understanding of this rare disease. Prospective data collection will allow a fuller analysis of poor prognostic features, impact of therapy, and variable outcome of childhood myositis.

Adolescent↗
PubMed2005

Expansion and enhanced survival of natural killer cells expressing the killer immunoglobulin-like receptor KIR3DL2 in spondylarthritis.

OBJECTIVE: The spondylarthritides (SpA) are strongly associated with possession of HLA-B27. We hypothesized that the expression of abnormal forms of HLA-B27 in SpA may have a pathogenic role through interaction with cells bearing natural killer (NK) receptors, in particular, killer immunoglobulin-like receptor (KIR) KIR3DL2, a receptor for HLA-B27 homodimer (B27(2)). We therefore undertook the present study to determine the number and function of NK and T cells bearing KIR3DL2 in SpA. METHODS: Expression of KIR3DL2 on NK and T cells was quantified in peripheral blood (PB) from 35 patients with SpA and 5 patients with juvenile enthesitis-related arthritis (juvenile ERA); samples were compared with samples from healthy and rheumatoid arthritis (RA) controls. Paired synovial fluid (SF) was studied where available. Expression of other KIRs as well as activation, memory, and homing markers on KIR3DL2+ NK and T cells was quantified. NK cell survival was assessed using the apoptotic markers annexin V and 7-aminoactinomycin D, and cytotoxicity by (51)Cr release assay. RESULTS: In SpA, an increased number of PB and SF NK and CD4+ T cells expressed the KIR3DL2 receptor compared with controls. In ERA, KIR3DL2 expression was increased in PB and SF CD4 T cells (and SF NK cells) compared with RA controls. KIR3DL2+ NK cells had an activated phenotype, and were protected from apoptosis by culture with a cell line expressing B27(2). SpA PB mononuclear NK cells from SpA patients showed greater cytotoxicity than those from controls. CONCLUSION: KIR3DL2 expression on NK cells and CD4 lymphocytes is increased in SpA and ERA. These cells are activated and may have a pathogenic role.

Adolescent↗
PubMed2004

Quantitative assessment of MRI T2 relaxation time of thigh muscles in juvenile dermatomyositis.

OBJECTIVE: The aim of the study was to examine the validity and reliability of a quantifiable measure of inflammation using magnetic resonance imaging (MRI) in children with juvenile dermatomyositis (JDM). METHODS: Children with active JDM, inactive JDM and healthy children received detailed assessments of recognized measures of muscle inflammation including muscle strength (manual muscle testing and myometry) and function (Childhood Myositis Assessment Scale, Childhood Health Assessment Questionnaire), the muscle enzymes lactate dehydrogenase (LDH) and creatine kinase (CK) and T2-weighted MRI scans of the thigh muscles, and these values were correlated with each other. RESULTS: Ten children with active JDM, 10 with inactive JDM and 20 healthy children completed the study. There was no significant difference in ages between the three groups. The MRI T2 relaxation times were significantly increased in active JDM compared with inactive JDM and healthy children (P = 0.05), indicating a detectable increase in inflammation within the muscles. There were also good correlations between the MRI scores and the measures of muscle strength and function; however, there was no correlation between the MRI and muscle enzymes. CONCLUSIONS: The MRI T2 relaxation time can be used as a quantitative measure of muscle inflammation and it has good correlations with other measures of disease activity.

Adolescent↗
PubMed2004

Intravenous cyclophosphamide pulse therapy in juvenile dermatomyositis. A review of efficacy and safety.

OBJECTIVES: To assess the efficacy and safety of intravenous cyclophosphamide (CYP) used in severe and refractory juvenile dermatomyositis (JDM). METHODS: Retrospective case note review of the outcome of 12 patients. RESULTS: Assessment at 6 months of therapy in 10 of the 12 patients showed a significant improvement in muscle function as assessed by the Childhood Myositis Assessment Scale (CMAS) (P = 0.012), muscle strength (P = 0.008), global extramuscular disease score (P = 0.008), skin disease severity (P = 0.015) and lactate dehydrogenase (P = 0.028). There were reductions in creatine kinase, alanine aminotransferase, prednisolone dose and ESR, but these did not reach statistical significance. Clinical improvement was maintained after CYP until the most recent follow-up (between 6 months and 7 yr) and no severe side-effects were seen. Reversible complications included lymphopenia, herpes zoster infections and alopecia. The median cumulative dose was 4.6 g/m(2) (range 3-9 g/m(2)). The available evidence suggests that, at the doses required, risks of malignancy, infertility and gonadal failure are low. Two patients with severe treatment-resistant disease died after one dose of CYP, both of whom were ventilated prior to commencement of CYP and were thought to have died as a result of their severe disease process, and too early for clinical benefit to be obtained from the drug. CONCLUSIONS: In this cohort of children with severe and refractory JDM, CYP appeared to have provided major clinical benefit with no evidence of serious toxicity in the short term.

Antirheumatic Agents↗
PubMed2004

Autologous stem cell transplantation for refractory juvenile idiopathic arthritis: analysis of clinical effects, mortality, and transplant related morbidity.

OBJECTIVE: To evaluate the safety and efficacy of autologous stem cell transplantation (ASCT) for refractory juvenile idiopathic arthritis (JIA). DESIGN: Retrospective analysis of follow up data on 34 children with JIA who were treated with ASCT in nine different European transplant centres. Rheumatological evaluation employed a modified set of core criteria. Immunological reconstitution and infectious complications were monitored at three month intervals after transplantation. RESULTS: Clinical follow up ranged from 12 to 60 months. Eighteen of the 34 patients (53%) with a follow up of 12 to 60 months achieved complete drug-free remission. Seven of these patients had previously failed treatment with anti-TNF. Six of the 34 patients (18%) showed a partial response (ranging from 30% to 70% improvement) and seven (21%) were resistant to ASCT. Infectious complications were common. There were three cases of transplant related mortality (9%) and two of disease related mortality (6%). CONCLUSIONS: ASCT in severely ill patients with JIA induces a drug-free remission of the disease and a profound increase in general wellbeing in a substantial proportion of patients, but the procedure carries a significant mortality risk. The following adjustments are proposed for future protocols: (1) elimination of total body irradiation from the conditioning regimen; (2) prophylactic administration of antiviral drugs and intravenous immunoglobulins until there is a normal CD4+ T cell count.

Arthritis, Juvenile↗
PubMed2003

Synovial dendritic cells in juvenile idiopathic arthritis (JIA) express receptor activator of NF-kappaB (RANK).

OBJECTIVES: To analyse the expression of receptor activator of NF-kappaB (RANK) and RANK ligand (RANKL) in the joints of children with juvenile idiopathic arthritis (JIA), to characterize the phenotype of RANK(+) cells and to test the hypothesis that some RANK(+) cells are of the dendritic type. METHODS: Paired samples of peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) from children with oligoarticular (n=14) or polyarticular (n=4) JIA and PBMC from 10 control subjects were studied for expression of RANK, RANKL and dendritic cell-specific ICAM (intercellular adhesion molecule)-grabbing non-integrin (DC-SIGN) by the reverse transcriptase-polymerase chain reaction and three-colour flow cytometry. Expression of DC-SIGN and RANK was followed after 1 week of culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4). RESULTS: mRNA for RANK was detected in both adherent cells and T cells from PBMC and SFMC of patients with JIA and in control PBMC, while mRNA for RANKL was detectable in the T-cell fraction from JIA patients but not in that from controls. By flow cytometry, a large number of RANK(+) cells were detected in the joint; these cells had the phenotype HLA-DR(hi)CD86(hi) CD11c(+) and expressed low levels of DC-SIGN. CONCLUSIONS: There is increased expression of RANKL and RANK in the juvenile arthritic joint. RANK is expressed on a population of cells with features of dendritic cells. RANK/RANKL interactions may contribute to the survival of inflammatory cells within the joint, as well as to erosions and osteoporosis in juvenile arthritis.

Adult↗
PubMed2001

T cell activation by coxsackievirus B4 antigens in type 1 diabetes mellitus: evidence for selective TCR Vbeta usage without superantigenic activity.

Numerous clinical and epidemiological studies link enteroviruses such as the Coxsackie virus group with the autoimmune disease type 1 diabetes mellitus (DM). In addition, there are reports that patients with type 1 DM are characterized by skewing of TCR Vbeta chain selection among peripheral blood and intraislet T lymphocytes. To examine these issues, we analyzed TCR Vbeta chain-specific up-regulation of the early T cell activation marker, CD69, on CD4 T cells after incubation with Coxsackievirus B4 (CVB4) Ags. CD4 T cells bearing the Vbeta chains 2, 7, and 8 were the most frequently activated by CVB4. Up-regulation of CD69 by different TCR families was significantly more frequent in new onset type 1 DM patients (p = 0.04), 100% of whom (n = 8) showed activation of CD4 T cells bearing Vbeta8, compared with 50% of control subjects (n = 8; p = 0.04). T cell proliferation after incubation with CVB4 Ags required live, nonfixed APCs, suggesting that the selective expansion of CD4 T cells with particular Vbeta chains resulted from conventional antigen processing and presentation rather than superantigen activity. Heteroduplex analysis of TCR Vbeta chain usage after CVB4 stimulation indicated a relatively polyclonal, rather than oligo- or monoclonal response to viral Ags. These results provide evidence that new-onset patients with type 1 DM and healthy controls are primed against CVB4, and that CD4 T cell responses to the virus have a selective TCR Vbeta chain usage which is driven by viral Ags rather than a superantigen.

Adult↗
PubMed2001

The developing human immune system: T-cell receptor repertoire of children and young adults shows a wide discrepancy in the frequency of persistent oligoclonal T-cell expansions.

While the T-cell receptor (TCR) repertoire of the newborn is highly diverse, a gradual alteration in diversity of the expressed TCR repertoire, in particular the oligoclonality of CD8+ T cells, occurs with increasing age. The timing of the initiation of this process is unknown. These changes are associated with an accumulation of T-cell expansions, thought to be in response to chronic antigen stimulation, frequently by persistent viruses such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Using reverse transcription-polymerase chain reaction heteroduplex analysis we have characterized the TCR expression of CD4 and CD8 cells from healthy young children and adults in order to delineate the age range at which these oligoclonal populations appear. We demonstrate that considerable oligoclonality can occur, even in healthy young children, and also that these expanded clonotypes persist. These are shown by heteroduplex to be exclusively within the CD28- subpopulation. The presence of such oligoclonal expansions correlates closely with the percentage of CD8+ cells that have the CD28- phenotype. However, we also show that control of chronic infection with EBV or CMV may coexist with a highly diverse, polyclonal TCR repertoire well into adulthood. These studies suggest that many factors affect the overall regulation of clone size in response to chronic antigens during the development of the immune system.

Adolescent↗
PubMed2001

Divergence in the degree of clonal expansions in inflammatory T cell subpopulations mirrors HLA-associated risk alleles in genetically and clinically distinct subtypes of childhood arthritis.

Clinically distinct forms of childhood arthritis are associated with different risk alleles of polymorphic loci within the MHC, which code for the antigen-presenting class I or class II molecules. We have compared the TCR diversity of synovial T cells from children with enthesitis-related (HLA-B27(+)) arthritis and oligoarticular arthritis (with class II MHC risk allele associations) in parallel with peripheral blood T cells from each child, using a high-resolution heteroduplex TCR analysis. We demonstrate that multiple clonal T cell expansions are present and persistent within the joint in both groups, but that there is disease-specific divergence in the dominant T cell subset containing these expansions. Thus, the largest clonotypes within the inflamed joints of children with class II-associated arthritis are within the CD4(+) synovial T cell population, while the dominant clones from children with enthesitis-related arthritis (associated with a class I allele) are within the CD8(+) synovial T cell population. These data provide powerful data to support the concept that recognition of MHC-peptide complexes by T cells plays a role in the pathogenesis of juvenile arthritis.

Alleles↗
PubMed2001

Autologous stem cell transplantation for paediatric-onset polyarteritis nodosa: changes in autoimmune phenotype in the context of reduced diversity of the T- and B-cell repertoires, and evidence for reversion from the CD45RO(+) to RA(+) phenotype.

We have studied immune reconstitution in a patient with paediatric-onset polyarteritis nodosa treated with high-dose immunosuppressive agents followed by stem cell rescue. The patient developed several new autoimmune phenomena over the 18 months after immunosuppression and stem cell rescue. Flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR) heteroduplex and isotype-specific RT-PCR analysis of immunoglobulin expression showed that the T- and B-cell repertoires were highly restricted in the first few months after treatment. The dominant T-cell clones seen after reconstitution were persistently expanded, were different from those which could be demonstrated before autologous stem cell transplantation, and were in the CD8(+) population. Our data also show that 12 months after treatment these expanded T-cell clones were within the CD45RA(+) population, suggesting that reversion from the CD45RO(+) to the CD45RA(+) phenotype had occurred in vivo.

Adult↗
PubMed2000

Clonal expansions in acute EBV infection are detectable in the CD8 and not the CD4 subset and persist with a variable CD45 phenotype.

We have applied a sensitive global analysis of TCR heterogeneity to compare clonal dynamics of CD4(+) and CD8(+) T cells in acute infectious mononucleosis. Using this approach, we are able to identify a broad representation of the total virus-specific population without the bias of in vitro culture and then to track their phenotype and fate by their unique molecular footprint. We demonstrate a large number of Ag-driven clones using different TCRs in the acute phase, all CD8(+). The diverse large clones generated in the CD8 subset in response to this virus contrast with the complete lack of detectable clonal expansion in the CD4 compartment. Many of the same clones remain detectable in directly ex vivo CD8(+) T cells for at least a year after resolution of infectious mononucleosis, although the clone size is reduced. Thus, memory CD8 cells following EBV infection persist at relatively high circulating frequency and represent a subset of the large range of clonotypes comprising the acute effectors. Separation of samples into CD45RA (naive) and CD45RO (memory) fractions shows the accumulation of identical CDR3 region defined clonotypes in both CD45RO and CD45RA fractions and sequencing confirms that dominant long-lived monoclonal expansions can reside in the CD45RA pool.

Acute Disease↗
PubMed2000

Selective recruitment of polarized T cells expressing CCR5 and CXCR3 to the inflamed joints of children with juvenile idiopathic arthritis.

OBJECTIVE: To study the expression of chemokine receptors CCR5 and CXCR3 and the Th1/Th2 cytokine balance in children with oligoarticular or polyarticular juvenile idiopathic arthritis (JIA). METHODS: Using 3-color immunofluorescence, we studied the expression of CCR5 and CXCR3 on, and T cell cytokine production by, paired samples of synovial fluid (SF) and peripheral blood (PB) T cells from 20 patients with oligoarticular- or polyarticular-onset JIA. Chemokine and cytokine phenotypes were also compared within the CD45RO+,CD3+ subsets. CCR5 genotypes were confirmed by polymerase chain reaction typing and sequencing. RESULTS: In the majority of samples, the number of T cells that were CCR5+ and CXCR3+ was higher in SF than in PB, and this difference was significant. One child was homozygous for the null A32 CCR5 allele; 4 others had lower expression of CXCR3 in SF than in blood. All samples showed strongly Th1-type cytokine production by synovial T cells compared with that by PB T cells. Both features were also markedly polarized within the synovial CD45RO+ subset compared with PB CD45RO+ T cells. CONCLUSION: The high expression of CCR5 and CXCR3 and high interferon-gamma:interleukin-4 ratios suggest a type 1 phenotype of SF T cells in JIA. The difference between CD45RO+ T cells from SF and from PB suggests that specific activation events have occurred in synovial T cells. We suggest that the highly activated, Th1-type phenotype of T cells within the chronically inflamed joints of children with JIA may reflect specific recruitment events that contribute to the polarization of these cells.

Adolescent↗