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Objectives: To predict the occurrence of inactive disease in JIA in the first 2 years of disease., Methods: An inception cohort of 152 treatment-naïve JIA patients with disease duration <6 months was analysed. Potential predictors were baseline clinical variables, joint US, gut microbiota composition and a panel of inflammation-related compounds in blood plasma. Various algorithms were employed to predict inactive disease according to Wallace criteria at 6-month intervals in the first 2 years. Performance of the models was evaluated using the split-cohort technique. The cohort was analysed in its entirety, and separate models were developed for oligoarticular patients, polyarticular RF negative patients and ANA positive patients., Results: All models analysing the cohort as a whole showed poor performance in test data [area under the curve (AUC): <0.65]. The subgroup models performed better. Inactive disease was predicted by lower baseline juvenile arthritis DAS (JADAS)-71 and lower relative abundance of the operational taxonomic unit Mogibacteriaceae for oligoarticular patients (AUC in test data: 0.69); shorter duration of morning stiffness, higher haemoglobin and lower CXCL-9 levels at baseline for polyarticular RF negative patients (AUC in test data: 0.69); and shorter duration of morning stiffness and higher baseline haemoglobin for ANA positive patients (AUC in test data: 0.72)., Conclusion: Inactive disease could not be predicted with satisfactory accuracy in the whole cohort, likely due to disease heterogeneity. Interesting predictors were found in more homogeneous subgroups. These need to be validated in future studies.

Objective: The aim of this study was to investigate the current use of musculoskeletal US (MSUS) and the most relevant areas of interest for this imaging modality in paediatric rheumatology., Methods: A questionnaire was developed by the paediatric subgroup of the OMERACT US task force and e-mailed to the members of the main international paediatric rheumatology networks and societies. Responses were entered in an electronic database. Results were analysed quantitatively or summarized qualitatively in the case of open questions., Results: The overall response rate was 36% (262/719). The use of MSUS varied among members of the various networks/societies. MSUS was considered of high relevance for improvement of diagnostic skills, for the guidance of joint injections and for the assessment of specific joints, namely the hip, ankle, midfoot and wrist. It was considered useful for early detection of synovitis and in determining disease activity and disease remission., Conclusion: Although at present MSUS is not widely used by paediatric rheumatologists, there is considerable interest in this imaging technology among members of the international networks. The results of this survey suggest that the next objective in the research agenda should be the standardization of the assessment of joints in healthy children. This will then help differentiate pathological (i.e. synovitic) joints from normal joints. The initial target joints should be the hip, ankle, midfoot and wrist. MSUS training focused on the assessment of paediatric patients might be very important in implementing the use of this technique in clinical practice and research.

US is a powerful tool for the assessment of joint synovitis in children with JIA and has been shown to be more accurate than clinical examination in detecting synovial disease. Recent studies have documented the presence of US-detected synovial pathology in children with JIA in clinical remission. US assessment enables the differentiation of joint synovitis from tenosynovitis, may help detect enthesitis and is valuable for capturing cartilage damage and early bone erosions. Guidance to local injection therapy represents an important application of US in routine care. Although US has a great potential for diffusion among paediatric rheumatologists, several issues need to be addressed. In particular, a thorough knowledge of US anatomy of joints in growing children is necessary to interpret US findings in JIA patients. The present review examines the potential role of US in the assessment of joint disease in children with JIA.

Objectives: To investigate the efficacy of IA CS (IAC) therapy in single and multiple joints in children with JIA and to seek for predictors of synovitis flare., Methods: The clinical charts of patients who received their first IAC injection between January 2002 and December 2008 were reviewed. The CS used was triamcinolone hexacetonide for large joints and methylprednisolone acetate for small or difficult to access joints. Patients were stratified as follows: one joint injected; two joints injected; and three or more joints injected. Predictors included sex, age at disease onset, JIA category, age and disease duration, ANA status, iridocyclitis, general anaesthesia, number and type of injected joints, acute-phase reactants and concomitant MTX therapy., Results: The cumulative probability of survival without synovitis flare for patients injected in one, two, or three or more joints was 70, 45 and 44%, respectively, at 1 year; 61, 32 and 30%, respectively, at 2 years; and 37, 22 and 19%, respectively, at 3 years. On Cox regression analysis, positive CRP, negative ANA and injection in the ankle were the strongest predictors for synovitis flare. The only significant side effect was skin hypopigmentation or s.c. atrophy, which occurred in <2% of patients., Conclusion: IAC therapy-induced sustained remission of synovitis in a substantial proportion of patients injected either in single or multiple joints, with a good safety profile. The risk of synovitis flare was higher in patients who had positive CRP, negative ANA and were injected in the ankle.

Objective: To develop and validate a new short and simple measure of health-related quality of life (HRQL) in children with juvenile idiopathic arthritis (JIA)., Methods: The Paediatric Rheumatology Quality of Life Scale (PRQL) is a 10-item questionnaire that explores HRQL in two domains: physical health (PhH) and psychosocial health (PsH). Validation of the parent proxy report and child self-report versions of the instrument was accomplished by evaluating 472 JIA patients and approximately 800 healthy children. Validation analyses included assessment of feasibility, face and content validity; construct and discriminative ability; internal structure and consistency; test-retest reliability; responsiveness to clinical change; and minimal clinically important difference., Results: The PRQL was found to be feasible and to possess both face and content validity. The PRQL score correlated in the predicted range with most of the other JIA outcome measures, thereby demonstrating good construct validity, and discriminated well between different levels of disease severity. Assessment of internal structure (factor analysis) revealed that the PhH and PsH subscales identify two unambiguously separated domains. The internal consistency (Cronbach's alpha) was 0.86. The intraclass correlation coefficient for test-retest reliability was 0.91. The PRQL revealed fair responsiveness, with a standardized response mean of 0.67 in improved patients. Overall, the PRQL appeared to be more able to capture physical HRQL than psychosocial HRQL., Conclusion: The PRQL was found to possess good measurement properties and is, therefore, a valid instrument for the assessment of HRQL in children with JIA. This tool is primarily proposed for use in standard clinical care.

Objective: Macrophage activation syndrome (MAS) in systemic onset juvenile idiopathic arthritis (SoJIA) is considered to be an acquired form of familial haemophagocytic lymphohistiocytosis (fHLH). FHLH is an autosomal recessive disorder, characterized by diminished NK cell function and caused by mutations in the perforin gene (PRF1) in 20-50% of patients. Interestingly, SoJIA patients display decreased levels of perforin in NK cells and diminished NK cell function as well. Here, we analysed PRF1 and its putative promoter in SoJIA patients with or without a history of MAS., Methods: DNA of 56 SoJIA patients (41 Italian and 15 Dutch) was isolated. Of these, 15 (27%) had a confirmed history of MAS. We sequenced PRF1 and 1.5 kb of the 5'-upstream region. DNA sequence variations in the promoter region were functionally tested in transfection experiments using a human NK cell line., Results: We detected a previously undescribed sequence variation (-499 C > T) in the promoter of PRF1 in 18% of the SoJIA patients. However, transfection experiments did not show functional implications of this variation. Secondly, we found that 11 of 56 (20%) SoJIA patients were heterozygous for missense mutations in PRF1. In particular, we found a high prevalence of the Ala91Val mutation, a variant known to result in defective function of perforin. Interestingly, the prevalence of Ala91Val in SoJIA patients with a history of MAS (20%) was increased compared with SoJIA patients without MAS (9.8%). One SoJIA patient, heterozygous for Ala91Val, showed profound decreased perforin levels at the time of MAS., Conclusions: These findings suggest that PRF1 mutations play a role in the development of MAS in SoJIA patients.

Objectives: To determine whether demographic, clinical and immunological features may predict the outcome in juvenile SSc (JSSc)., Methods: Clinical and laboratory characteristics of patients with JSSc collected from paediatric rheumatology centres worldwide were analysed. First, univariate tests identified those features significantly related with fatal outcome, and then multivariate logistic regression analysis was applied to determine the predictors of mortality., Results: One hundred and thirty-four patients from 40 centres were eligible for the analysis. Sixteen patients died and a rapidly fatal course was observed in most of them: 4/16 died within 1 yr after diagnosis and 10/16 within 5 yrs. At the moment of diagnosis, patients with poor outcome showed a significantly higher frequency of internal organ involvement, particularly cardiac, respiratory and gastrointestinal systems. No significant difference emerged for entity of skin, vascular and musculo-skeletal involvement, nor for auto-antibodies profile and laboratory tests. Multivariate analysis showed the following factors to be significant predictors of mortality: fibrosis on chest X-rays [odds ratio (OR) 11.2], raised creatinine levels (OR 22.7) and pericarditis (OR 41.3), while a short disease duration at diagnosis conferred protection (OR 0.3)., Conclusions: All patients with JSSc and fatal outcome were affected by the diffuse form of the disease, and most of them showed a very rapid progression and early signs of internal organ involvement. This suggests that, in children, SSc may have two possible courses: a rapid development of internal organ failure leading to severe disability and eventually to death, or a slow course of the disease with lower mortality.

Objective: To develop a scoring system for juvenile idiopathic arthritis (JIA) in which joints are weighted to reflect their relative importance to children's function and to examine whether weighting increases the correlation of joint counts with subjective and laboratory outcome measures., Methods: A weighted joint score was devised by a panel of experienced paediatric rheumatologists, who assigned a weight from 1 (not very important) to 10 (essential for key functional activities) to each joint based on its functional importance to children's physical and daily activities. The associations of simple and weighted counts of swollen, tender, limited and active joints with the physician's global assessment of overall disease activity, the parent's global assessment of the child's overall well-being and intensity of pain, the Childhood Health Assessment Questionnaire (C-HAQ), the Child Health Questionnaire (CHQ) and the erythrocyte sedimentation rate were compared using Spearman's correlation analysis in 60 unselected patients seen in the clinic and in 61 consecutive patients with disease duration > or = 5 yr., Results: Weighted counts of swollen and active joints yielded greater correlation with the physician's global assessment than did simple counts. The correlation of weighted counts of swollen, painful and active joints with the parent's assessment of overall well-being and intensity of pain was superior to that provided by simple counts. Weighting increased most of the correlations between joint counts and the C-HAQ score and the physical component of the CHQ., Conclusion: Weighting improves the information provided by joint counts on the severity of arthritis and its impact on patients' well-being.