A novel dried blood spot-LCMS method for the quantification of methotrexate polyglutamates as a potential marker for methotrexate use in children

Objective

Development and validation of a selective and sensitive LCMS method for the determination of methotrexate polyglutamates in dried blood spots (DBS).

Methods

DBS samples [spiked or patient samples] were prepared by applying blood to Guthrie cards which was then dried at room temperature. The method utilised 6-mm disks punched from the DBS samples (equivalent to approximately 12 µl of whole blood). The simple treatment procedure was based on protein precipitation using perchloric acid followed by solid phase extraction using MAX cartridges. The extracted sample was chromatographed using a reversed phase system involving an Atlantis T3-C18 column (3 µm, 2.1×150 mm) preceded by Atlantis guard column of matching chemistry. Analytes were subjected to LCMS analysis using positive electrospray ionization.

Key Results

The method was linear over the range 5–400 nmol/L. The limits of detection and quantification were 1.6 and 5 nmol/L for individual polyglutamates and 1.5 and 4.5 nmol/L for total polyglutamates, respectively. The method has been applied successfully to the determination of DBS finger-prick samples from 47 paediatric patients and results confirmed with concentrations measured in matched RBC samples using conventional HPLC-UV technique.

Conclusions and Clinical Relevance

The methodology has a potential for application in a range of clinical studies (e.g. pharmacokinetic evaluations or medication adherence assessment) since it is minimally invasive and easy to perform, potentially allowing parents to take blood samples at home. The feasibility of using DBS sampling can be of major value for future clinical trials or clinical care in paediatric rheumatology.

Synovial membrane immunohistology in early untreated juvenile idiopathic arthritis: differences between clinical subgroups

OBJECTIVE

Juvenile idiopathic arthritis (JIA) consists of a heterogeneous group of inflammatory disorders, within which there are a number of clinical subgroups. Diagnosis and assignment to a particular subgroup can be problematical and more concise methods of subgroup classification are required. This study of the synovial membrane characterises the immunohistochemical features in early untreated, newly diagnosed JIA and compares findings with disease subgroup at 2 years.

METHODS

42 patients with newly diagnosed untreated JIA underwent synovial biopsy before the administration of steroids or disease-modifying antirheumatic drugs. Patients were classified as either polyarticular, persistent oligoarticular or extended-to-be oligoarticular. The location and semiquantitative analysis of T-cell subsets, B cells, macrophages and blood vessels were determined using immunohistochemistry.

RESULTS

Synovial hyperplasia varied significantly between the three groups (p<0.0001). There was a significant difference in the CD3 T-cell population between the three groups (p=0.004) and between the extended-to-be and persistent group (p=0.032). CD4 expression was significantly higher in the poly and extended-to-be oligo groups (p=0.002), again the extended-to-be group had more CD4 T cells than the persistent group (p=0.008). B-cell infiltrates were more marked in the polyarticular group and were significantly higher in the extended-to-be group compared with the persistent group (p=0.005). Vascularisation was more pronounced in the polyarticular and extended-to-be oligoarticular groups, the extended-to-be group had significantly more vascularisation than the persistent group (p=0.0002).

CONCLUSIONS

There are significant differences in the histomorphometric features of synovial tissue between patient subgroups. Immunohistological examination of synovial membrane biopsies may provide further insight into early disease processes in JIA.

The Paediatric Rheumatology International Trials Organisation provisional criteria for the evaluation of response to therapy in juvenile dermatomyositis

OBJECTIVE

To develop a provisional definition for the evaluation of response to therapy in juvenile dermatomyositis (DM) based on the Paediatric Rheumatology International Trials Organisation juvenile DM core set of variables.

METHODS

Thirty-seven experienced pediatric rheumatologists from 27 countries achieved consensus on 128 difficult patient profiles as clinically improved or not improved using a stepwise approach (patient's rating, statistical analysis, definition selection). Using the physicians' consensus ratings as the "gold standard measure," chi-square, sensitivity, specificity, false-positive and-negative rates, area under the receiver operating characteristic curve, and kappa agreement for candidate definitions of improvement were calculated. Definitions with kappa values >0.8 were multiplied by the face validity score to select the top definitions.

RESULTS

The top definition of improvement was at least 20% improvement from baseline in 3 of 6 core set variables with no more than 1 of the remaining worsening by more than 30%, which cannot be muscle strength. The second-highest scoring definition was at least 20% improvement from baseline in 3 of 6 core set variables with no more than 2 of the remaining worsening by more than 25%, which cannot be muscle strength (definition P1 selected by the International Myositis Assessment and Clinical Studies group). The third is similar to the second with the maximum amount of worsening set to 30%. This indicates convergent validity of the process.

CONCLUSION

We propose a provisional data-driven definition of improvement that reflects well the consensus rating of experienced clinicians, which incorporates clinically meaningful change in core set variables in a composite end point for the evaluation of global response to therapy in juvenile DM.

IL7RA polymorphisms and chronic inflammatory arthropathies

The C allele of a single nucleotide polymorphism (SNP), rs6897932, located in the interleukin-7 receptor alpha chain (IL7RA) was recently found to be associated with multiple sclerosis and Type I diabetes. We analysed 13 SNPs in the IL7RA gene in a combined cohort of patients with chronic inflammatory arthropathies (rheumatoid arthritis and juvenile idiopathic arthritis; 368 patients and 532 unaffected subjects). No significant associations with disease were found with the exception of the non-synonymous SNP rs6897932. This SNP showed modest enrichment of the TT genotype in arthritic patients compared with controls [P = 0.02; OR 1.72 (95% CI 1.08-2.75)]. Our data are suggestive for a role of rs6897932 in predisposition to chronic inflammatory arthropathies.

Comparative analysis of synovial fluid and plasma proteomes in juvenile arthritis--proteomic patterns of joint inflammation in early stage disease

Synovial fluid is a potential source of novel biomarkers for many arthritic disorders involving joint inflammation, including juvenile idiopathic arthritis. We first compared the distinctive protein 'fingerprints' of local inflammation in synovial fluid with systemic profiles within matched plasma samples. The synovial fluid proteome at the time of joint inflammation was then evaluated across clinical subgroups to identify early disease associated proteins. We measured the synovial fluid and plasma proteomes using the two-dimensional fluorescence difference gel electrophoresis approach. Image analysis software was used to highlight the expression levels of joint and subgroup associated proteins across the study cohort (n = 32). A defined subset of 30 proteins had statistically significant differences (p < 0.05) between sample types such that synovial fluid could be differentiated from plasma. Furthermore distinctive synovial proteome expression patterns segregate patient subgroups. Protein expression patterns localized in the chronically inflamed joint therefore have the potential to identify patients more likely to suffer disease which will spread from a single joint to multiple joints. The proteins identified could act as criteria to prevent disease extension by more aggressive therapeutic intervention directed at an earlier stage than is currently possible.

A systematic review of the effectiveness of strategies for reducing fracture risk in children with juvenile idiopathic arthritis with additional data on long-term risk of fracture and cost of disease management

OBJECTIVES

To review outcome measures and treatment costs in children with juvenile idiopathic arthritis (JIA) and low bone mineral density (BMD) and/or fragility fractures. To review evidence for effectiveness and safety of bisphosphonates and calcium and/or vitamin D in these children. To assess long-term bone health in adults with JIA.

DATA SOURCES

Major databases were searched up to July 2005 for effectiveness studies and up to January 2005 for costs.

REVIEW METHODS

A structured search strategy was conducted. For the evaluation of long-term bone health, outcome data were derived from two cohorts of adult patients with JIA. As there were few published cost data, an ongoing UK longitudinal study (CAPS) provided background data on the cost of managing JIA.

RESULTS

Sixteen studies (78 children with JIA) were included. At baseline, the children had BMD below the expected values for age- and sex-matched children; treatment with bisphosphonates increased BMD with mean percentage increases in spine BMD varying from 4.5 to 19.1%. None of the studies with control groups compared results between the intervention and control groups, they only compared each group with its own baseline. Overall, studies were heterogeneous in design, of variable quality and with no consistency in methods of assessing and reporting outcomes. Hence, data could not be combined or an effect size calculated. A further 43 papers were included in the safety review; side-effects were generally transient. Two studies assessed treatment with calcium and/or vitamin D; BMD was increased from 0.75 to 0.830 g/cm2 after 6 months and BMD Z-score from -2.8 to -2.3 after 6 months and -2.4 after 1 year. There are relatively few long-term studies on the occurrence of low BMD and fragility fractures in children with JIA, with most studies only following children for 1 or 2 years. However, the long- and short-term data indicate that children with JIA have a lower BMD and more fractures than children without JIA. There are very few data on long-term bone health from adults who have JIA, but studies indicate that low BMD persists into adulthood, although adults in remission from JIA may attain the same BMD as healthy adults. From the available data, any predictors of low BMD and fractures in children and adults with JIA remain uncertain. No studies were found that discussed the costs of treating children with JIA and low BMD and/or fragility fractures. In CAPS, 297 of 457 children with JIA attended a 12-month follow-up visit. The mean annual total cost per child in the first year after diagnosis was 1649 pounds (standard deviation 1093 pounds, range 401-6967 pounds). The highest cost component was appointments with paediatric rheumatologists. The study is continuing to accrue and follow up patients and further analyses will be undertaken as the study progresses.

CONCLUSIONS

BMD, adjusted for size, should be assessed as the primary outcome in studies of bone health in children with JIA. Quantitative computed tomography could be used where equipment is available as it offers the advantage of measuring volumetric density. Bisphosphonates are a promising treatment for osteoporosis in children with JIA, but the quality of the current evidence is poor. The accurate assessment of outcome is crucial. There are still uncertainties about the use of bisphosphonates in children, including whether the positive effects of treatment continue over time, the length of treatment and the maximal bone mass gain that can be achieved. Adults with JIA may have persistent low BMD compared with an otherwise healthy population together with an increased risk of fracture. There are no studies evaluating the costs of treating children with JIA and low BMD and/or fragility fractures. There are few data evaluating the costs of treating JIA in general. In the first 12 months after diagnosis, children with all JIA disease subtypes consume large, but highly variable, quantities of health service resources, the largest component being the consultant rheumatology appointments. Data from a larger cohort, over a longer period, are required to substantiate these results further. Further research is needed to assess more clearly the role and permit licensing of bisphosphonates for treatment of children, and in particular, longer-term studies.

The MHC2TA-168A/G and +1614G/C polymorphisms and risk for multiple sclerosis or chronic inflammatory arthropathies

The -168A-G polymorphism has been shown to influence transcription of the MHC2TA gene and has been implicated in several inflammatory/autoimmune disorders. Attempts to reproduce these findings have been inconclusive. We investigated the role of this promoter single nucleotide polymorphism (SNP) in 440 multiple sclerosis (MS), 293 rheumatoid arthritis (RA), 74 juvenile idiopathic arthritis (JIA) patients and 316 healthy controls from Northern Ireland. We also genotyped a non-synonymous SNP in exon 11, +1614G/C. There was no significant difference in the -168G allele frequencies and carriage rates in the separate RA, JIA, or MS collections compared with the control group [odds ratio (OR) = 1.1, 95% confidence intervals (CI) = 0.86-1.44; OR = 1.1, 95% CI = 0.75-1.68; OR = 1.1, 95% CI = 0.84-1.35, respectively]. Assessment of the common phenotype (chronic inflammatory disease; n = 807 vs 316 controls) was negative as well. Carriage of +1614C was protective against JIA (OR = 0.6, 95% CI = 0.3-1.0) and showed a similar trend in RA and MS (OR = 0.7, 95% CI = 0.5-1.0; OR = 0.8, 95% CI = 0.6-1.0, respectively). The common phenotype (chronic inflammatory disease) was also significant (OR = 0.7, 95% CI = 0.6-1.0).

Polymorphisms in the interleukin-4 and IL-4 receptor genes modify risk for chronic inflammatory arthropathies in women

Rheumatoid and juvenile idiopathic arthritis (RA, JIA) are chronic inflammatory arthropathies with polygenic autoimmune background. We analysed the IL-4 +33 C/T and IL-4R Q551R single nucleotide polymorphisms (SNPs) in 294 RA, 72 JIA and 165 controls from Northern Ireland. Analysis of the individual phenotypes (RA or JIA) showed that both the IL-4 +33 TT (P = 0.02; OR: 0.25, 95% CI: 0.07-0.87) and the IL-4R Q551R CC genotypes (P = 0.001; OR: 0.19, 95% CI: 0.06-0.56) were exclusively decreased in female RA patients compared to female controls. Similar non-significant trends were observed in female JIA patients (OR: 0.25, 95% CI: 0.03-2.11 and OR: 0.31, 95% CI: 0.07-1.47, respectively). Analysis of the common phenotype (inflammatory arthropathy; i.e. JIA and RA combined) corroborated the unique association of these polymorphisms with female inflammatory arthropathy (P = 0.013 and 0.002, respectively). This is the first demonstration of sex-specific association of the two foremost genes of the IL-4 signalling cascade with chronic inflammatory arthropathies.

Neurological abnormalities in young adults born preterm

OBJECTIVE

Individuals born before 33 weeks' gestation (very preterm, VPT) have an increased likelihood of neurological abnormality, impaired cognitive function, and reduced academic performance in childhood. It is currently not known whether neurological signs detected in VPT children persist into adulthood or become attenuated by maturation of the CNS.

METHOD

We assessed 153 VPT individuals and 71 term-born controls at 17-18 years old, using a comprehensive neurological examination. This examination divides neurological signs into primary and integrative domains, the former representing the localising signs of classical neurology, and the latter representing signs requiring integration between different neural networks or systems. Integrative signs are sub-divided into three groups: sensory integration, motor confusion, and sequencing. The VPT individuals have been followed up since birth, and neonatal information is available on them, along with the results of neurological assessment at 4 and 8 years of age and neuropsychological assessment at 18 years of age.

RESULTS

The total neurology score and primary and integrative scores were significantly increased in VPT young adults compared to term-born controls. Within the integrative domain, sensory integration and motor confusion scores were significantly increased in the VPT group, but sequencing was not significantly different between the VPT and term groups. Integrative neurological abnormalities at 18 were strongly associated with reduced IQ but primary abnormalities were not.

CONCLUSIONS

Neurological signs are increased in VPT adults compared to term-born controls, and are strongly associated with reduced neuropsychological function.

Musculoskeletal ultrasound training in rheumatology: the Belfast experience

OBJECTIVES

Despite the increasing use of musculoskeletal ultrasound (MSUS) as a clinical tool in rheumatology, there is no consensus yet regarding the standards required to achieve a basic level of competence in the use of this imaging technique. A number of sonographers worldwide are developing curricula and standardizing teaching methods in order to improve training in MSUS for rheumatologists. In the meantime, clinicians are devising informal means of training in order to acquire these new skills. Here we describe the informal team approach to MSUS training adopted by a group of rheumatologists from the Regional Rheumatology Centre in Belfast, UK.

METHODS

Over a 5-yr period, eight rheumatologists from Musgrave Park Hospital in Belfast used a variety of means to learn the basic skills of MSUS.

RESULTS

Seven of the team underwent a formal assessment of their competency in a practical examination devised by an experienced sonographer. All were judged to have attained a basic competency in MSU.

CONCLUSIONS

This Belfast experience shows what can be achieved despite the absence of formal MSUS training. Nevertheless, the development of recognized training programmes and international standards of competency are important goals on the way to achieving more widespread acceptance of MSUS as a useful tool in everyday clinical practice.

The CTLA4+49A/G and CT60 polymorphisms and chronic inflammatory arthropathies in Northern Ireland

Rheumatoid and juvenile idiopathic arthritis (RA, JIA) are chronic inflammatory arthropathies with an autoimmune background. The cytotoxic T-lymphocyte antigen-4 (CTLA-4) protein plays a key role in the down-regulation of T cell activation. We analyzed the CTLA4 +49A/G and CT60 polymorphisms in cohorts of Northern Irish RA and JIA patients and healthy control subjects using restriction fragment length polymorphism methods. The +49 A allele was increased in RA (61.2%; P=0.02; OR=1.28; 95% C.I.=1.04-1.58) and JIA (61.8%; P=0.14) patients compared to the control population (55.3%). No significant association was observed for the CT60 polymorphism. Haplotype analysis revealed a significantly different distribution of +49 A/G-CT60 haplotypes in RA and JIA patients compared to controls (P value<0.00001 and 0.030 for comparison of RA and JIA patients with controls, respectively). Our results suggest that the CTLA-4 gene is involved in predisposition to inflammatory arthropathies in the Northern Irish population.

Polymorphisms in the interferon-γ/interleukin-26 gene region contribute to sex bias in susceptibility to rheumatoid arthritis

OBJECTIVE

To determine whether polymorphisms in the interferon-gamma (IFNgamma)/interleukin-26 (IL-26; formerly, AK155) gene cluster contribute to sex-based differential susceptibility to rheumatoid arthritis (RA).

METHODS

Four microsatellite markers, located in a 118-kb interval that contains both the IFNgamma and IL-26 genes on chromosome 12q15, were typed in 251 patients with RA and 198 unrelated healthy controls (all of whom lived in Northern Ireland) by means of polymerase chain reaction-based fragment analysis.

RESULTS

Marker D12S2510, which is located 3 kb 3' from the IL-26 gene, was significantly associated with RA in women (corrected P [P(corr)] = 0.008, 2 degrees of freedom [2 df]) but not in men (P = 0.99, 2 df). A 3-marker haplotype, IFNGCA*13;D12S2510*8;D12S2511*9, was inferred that showed significant underrepresentation in women with RA (odds ratio 0.50, 95% confidence interval 0.32-0.78; P = 0.002, P(corr) = 0.03) but not in men with RA.

CONCLUSION

Our results demonstrate that common polymorphisms in the IFNgamma/IL-26 gene region may contribute to sex bias in susceptibility to RA, by distorting the propensity of female carriers versus male carriers to contract this disease. These results conform to our recent observations of a role for this gene cluster in sex-based differential susceptibility to another Th1-type inflammatory disease, multiple sclerosis.