Impaired reproductive fitness in mothers of children with juvenile autoimmune arthropathies

OBJECTIVE

To assess the reproductive fitness of mothers of children with juvenile idiopathic arthritis (JIA).

METHODS

A mail survey assessing pregnancy outcome was carried out among mothers of children with JIA (JIA mothers) treated at a tertiary paediatric rheumatology centre. The best friends of the JIA mothers served as controls. Besides family history, sociodemographics and reproductive outcomes were measured, including the number of pregnancies, pregnancy complications and gestational age at the time of delivery.

RESULTS

JIA mothers (n = 227) and controls (n = 235) had similar sociodemographics and racial backgrounds. On average, JIA mothers reported a greater number of conceptions than controls (3.5 vs 3.1; P = 0.01) but had significantly higher rates of pregnancy complications (25% vs 15%; P<0.001). Corrected for differences in the absolute number of pregnancies between groups, the chances of having a miscarriage [mean (s.d.), 0.12 (0.18) vs 0.09 (0.16); P = 0.02] or preterm delivery [0.08 (0.21) vs 0.04 (0.15); P<0.02] were significantly greater among JIA mothers than controls.

CONCLUSIONS

Mothers of children with JIA have impaired reproductive fitness. This phenomenon is unlikely to be the result of difficulty with conception but rather to be due to higher rates of pregnancy loss and premature delivery.

Gene expression in juvenile arthritis and spondyloarthropathy: pro-angiogenic ELR+ chemokine genes relate to course of arthritis

OBJECTIVE

To evaluate the ability of microarray-based methods to identify genes with disease-specific expression patterns in peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) of juvenile arthritis patients and healthy controls.

METHODS

Microarray data (Affymetrix U95Av2) from 26 PBMC and 20 SFMC samples collected from patients with active disease (classified by course according to ACR criteria) were analysed for expression patterns that correlated with disease characteristics. For comparison, PBMC gene expression profiles were obtained from 15 healthy controls. Real-time PCR was used for confirmation of gene expression differences.

RESULTS

Statistical analysis of gene expression patterns in PBMC identified 378 probe sets corresponding to 342 unique genes with differing expression levels between polyarticular course patients and controls (t test, P<0.0001). The genes represented by these probe sets were enriched for functions related to regulation of immune cell functions, receptor signalling as well as protein metabolism and degradation. Included in these probe sets were a group of CXCL chemokines with functions related to angiogenesis. Further analysis showed that, whereas angiogenic CXCL (ELR+) gene expression was elevated in polyarticular PBMC, expression of angiostatic CXCL (ELR-) chemokines was lower in polyarticular SFMC compared with corresponding pauciarticular samples (t test, P<0.05).

CONCLUSIONS

This pilot study demonstrates that juvenile arthritis patients exhibit complex patterns of gene expression in PBMC and SFMC. The presence of disease-correlated biologically relevant gene expression patterns suggests that the power of this approach will allow better understanding of disease mechanisms, identify distinct clinical phenotypes in disease subtypes, and suggest new therapeutic approaches.

The Argentinian version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ)

We report herein the results of the cross-cultural adaptation and validation into the Argentinian language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Argentinian CHAQ was already published and therefore it was revalidated while the Argentinian CHQ was derived from the European Spanish version by changing few words which use is different in the 2 countries. A total of 124 subjects were enrolled: 61 patients with JIA (29% systemic onset, 38% polyarticular onset, 7% extended oligoarticular subtype, and 26% persistent oligoarticular subtype) and 63 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, and polyarticular having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Argentinian version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.

Age-specific effects of juvenile rheumatoid arthritis-associated HLA alleles

OBJECTIVE

To define the onset and duration of effect of the HLA alleles that are associated with disease susceptibility and protection in juvenile rheumatoid arthritis (JRA) and 2 of its subtypes.

METHODS

We typed 680 patients with JRA and 254 ethnically matched unrelated controls for HLA class I and II genes. The frequency of each allele was calculated for each of the age-at-onset, onset type, and sex categories and plotted against the allele frequency in the control population. Survival analysis (with onset of disease as the terminating event) was used to calculate the age by which 50% (St0.5) and 80% (St0.2) of the children with particular alleles and combinations of alleles develop disease. This allele-specific survival analysis also allowed for the comparison of the overall survival functions for the various JRA subtype and sex categories.

RESULTS

Certain alleles are strongly associated with early susceptibility to pauciarticular JRA, including HLA-A2, DR8, DR5, and DPB1*0201. Fifty percent of the children carrying at least 1 of these alleles had disease onset prior to their third birthday. Among children who carried HLA-A2 and any 2 HLA-DR alleles (DR3, DR5, DR6, or DR8), the median age at the onset of pauciarticular disease was 2.7 years. Combinations of A2 and DPB1*0201 and one DR allele narrowed the window further to a median age at onset of 2.4 years. B27 and DR4 were associated with protection early in life but with increased risk later in childhood, with St0.5 values of 7.3 and 6.6 years, respectively, for pauciarticular JRA and St0.5 values of 10.2 and 10.7 years, respectively, for polyarticular JRA. Sex strongly influenced the age at which many of the alleles have their effect.

CONCLUSION

These data define at what age and for how long various HLA alleles influence susceptibility and protection (window-of-effect) in patients with JRA. In addition, these data establish more clearly the boundaries of ages-at-onset for 2 of the subtypes of the disease.

Cross-cultural adaptation and validation of an Argentine Spanish Version of the Stanford Childhood Health Assessment Questionnaire

OBJECTIVES

To translate into Argentine Spanish and cross-culturally adapt the Childhood Health Assessment Questionnaire (CHAQ) and validate the adapted instrument in Argentine patients with juvenile rheumatoid arthritis (JRA).

METHODS

Five bilingual Argentine pediatric rheumatologists translated into Argentine Spanish and cross-culturally adapted the United States English CHAQ. Pretesting was done in a sample of 23 parents using a probe question technique. Parents of 70 patients with JRA and 21 healthy children (controls) participated in the validation phase. All were from Argentina.

RESULTS

The mean disability index (DI) scores for patients with systemic, polyarticular, or pauciarticular onset JRA were 0.64, 0.32, and 0.1, respectively. Healthy controls averaged 0.2. Intercomponent correlations were between 0.4 and 0.9, suggesting internal consistency, but also some redundancy. Test-retest reliability, studied at a 1-week interval, was moderate (mean DI 0.44 [in clinic] and 0.29 [one week later], Pearson's correlation = 0.82). We compared CHAQ scores from 15 parents with those of their children > 10 years of age. Significantly higher DI scores were given by patients than their respective parents (P > 0.019), but the pairwise scores (parent-patient) were highly correlated (r = 0.986).

CONCLUSIONS

Cross-cultural adaptation of the US CHAQ to Argentina required few changes. Although DI scores for all patient subgroups were higher than for controls subjects, the scores were low, particularly for those with pauciarticular disease. Prospective studies designed to examine the sensitivity to change and predictive validity will help to assess further the usefulness of the adapted CHAQ in the Argentine population.

Transmission disequilibrium as a test of linkage and association between HLA alleles and pauciarticular-onset juvenile rheumatoid arthritis

OBJECTIVE

To determine if HLA class I and II alleles previously found to be associated with (or protective against) pauciarticular-onset juvenile rheumatoid arthritis (pauci-onset JRA) in population-association studies are transmitted from heterozygous parents to an extent different from the expected 50%.

METHODS

One hundred one Caucasian North American families that had a child with pauci-onset JRA and at least 1 parent who was heterozygous for the allele of interest were available for analysis. Both biologic parents and all children (affected and unaffected) were typed for HLA class I and II alleles. The transmission disequilibrium test (TDT) was used to determine if affected offspring received the disease-associated (or protective) allele more (or less) frequently than its alternate allele. In families in which an unaffected sibling was available, the unmatched chi-square test was used to determine if a meiotic segregation distortion bias existed.

RESULTS

HLA class I alleles A2, B27, and B35 showed a significantly higher than expected frequency of transmission to affected offspring, as did class II alleles DR5 and DR8. HLA-DR4 was found to be transmitted significantly less frequently than expected to affected, but not unaffected, offspring. All alleles that showed an excess transmission to affected offspring were transmitted to unaffected offspring at expected rates. When the data were stratified by age and sex, the likelihood of transmission of some of the alleles was strongly influenced by these variables. For example, excess transmission of HLA-DR5 was found exclusively in female patients who were younger at the time of disease onset.

CONCLUSION

Results from these family-based studies rule out the possibility that HLA disease associations found in earlier studies were a result of population stratification and establish linkage and association between the major histocompatibility complex and pauci-onset JRA.

Estimates of the discriminant ability of definitions of improvement for juvenile rheumatoid arthritis

OBJECTIVE

To investigate the ability of various definitions of improvement to distinguish between patients with juvenile rheumatoid arthritis (JRA) treated with active drug from those given placebo in randomized trials.

METHODS

A core set of 6 response (outcome) variables for use in JRA has been reported. These core variables were combined into a number of "definitions of improvement" for the purpose of classifying individual patients as either "clinically significantly improved" or "not improved." We used a large dataset from randomized controlled trials to test the discriminant ability (sensitivity to change) of the definitions. We calculated the proportion of patients classified as "improved" by each definition in each of the treatment and control groups.

RESULTS

Effect sizes were weak in 4 of the treatment regimens used (D-penicillamine, hydroxychloroquine, auranofin, and very low dose methotrexate) and no definition discriminated well between drug and placebo treated groups. Definitions that required 20 to 30% improvement in 3 to 4 of the 6 core set variables showed statistically significant differences in the proportions of patients who were classified as improved in the group treated with low dose methotrexate (10 mg/m2 body surface area/wk) compared to placebo. A definition resembling the Paulus criteria used in adult RA trials (4 of 6 core set variables improved by > or = 20%) performed well, as did the definition selected previously as the best for JRA (3 of 6 core set variables improved by > or = 30%, not more than one worsening by > 30%).

CONCLUSION

Definitions that require 20 to 30% improvement in 3 to 4 core outcome variables are sensitive to change and are able to clearly distinguish between treated and control groups when an effective drug is being tested. Further testing of their validity is under way.

Juvenile rheumatoid arthritis in affected sibpairs

OBJECTIVE

To describe the demographics and clinical disease in affected sibpairs (ASPs) with juvenile rheumatoid arthritis (JRA), and to compare JRA as it occurs in ASPs with that from non-ASP JRA populations described in the literature.

METHODS

A rare disease research registry was established with a focus on JRA ASPs to facilitate accrual of patients for genetic, epidemiologic, and clinical studies. Physicians likely to care for patients with JRA were made aware of the registry and its goals by a variety of methods and asked to refer patients for entry.

RESULTS

To date, 71 ASPs have been registered and complete information has been obtained. These affected sibs differed in age by a mean of 4.1 years (SD 3.4) and in age at disease onset by 2.8 years (SD 3.0). The actual time difference between onset in sib 1 versus sib 2 averaged 4.4 years (SD 4.2). Sixty-three percent of the sibpairs were concordant for sex, and 76% for JRA onset type. Onset type within sibpairs did not appear to be random, based upon comparisons with non-ASP populations. Greater than expected concordance was seen among those with pauciarticular-onset and polyarticular-onset JRA. Seventy-nine percent of the pairs were concordant for course type. Seven sets of twins were included (approximately 10% of the total), all were concordant for onset and course type (6 sets with pauciarticular, 1 set with polyarticular), and disease onset was separated by a mean of only 3.3 months. Within the onset and course types, the clinical disease, such as the female:male ratio, age at onset, and serologic findings, in ASPs resembled that which has been described in the literature.

CONCLUSION

A higher than expected degree of concordance for onset type of JRA exists between sibpairs, indicating that genetic influences play a role. Affected sibs do not tend to develop their disease at approximately the same point in time, except for the twin sets. Clinical features of the disease within the various subtypes appear similar to those in non-ASP populations.