Performance of the 2016 ACR-EULAR myositis response criteria in juvenile dermatomyositis therapeutic trials and consensus profiles

OBJECTIVES

The 2016 ACR-EULAR Response Criteria for JDM was developed as a composite measure with differential weights of six core set measures (CSMs) to calculate a Total Improvement Score (TIS). We assessed the contribution of each CSM, representation of muscle-related and patient-reported CSMs towards improvement, and frequency of CSM worsening across myositis response criteria (MRC) categories in validation of MRC.

METHODS

Data from JDM patients in the Rituximab in Myositis trial (n = 48), PRINTO JDM trial (n = 139), and consensus patient profiles (n = 273) were included. Observed vs expected CSM contributions were compared using Sign test. Characteristics of MRC categories were compared by Wilcoxon tests with Bonferroni adjustment. Spearman correlation of changes in TIS and individual CSMs were examined. Agreement between physician-assessed change and MRC categories was evaluated by weighted Cohen's kappa.

RESULTS

Of 457 JDM patients with IMACS CSMs and 380 with PRINTO CSMs, 9-13% had minimal, 19-23% had moderate and 41-50% had major improvement. The number of improved and absolute percentage change of CSMs increased by MRC improvement level. Patients with minimal improvement by MRC had a median of 0-1 CSM worsened, and those with moderate/major improvement had a median of zero worsening CSMs. Of patients improved by MRC, 94-95% had improvement in muscle strength and 93-95% had improvement in ≥1 patient-reported CSM. IMACS and PRINTO CSMs performed similarly. Physician-rated change and MRC improvement categories had moderate-to-substantial agreement (Kappa 0.5-0.7).

CONCLUSION

The ACR-EULAR MRC perform consistently across multiple studies, supporting its further use as an efficacy end point in JDM trials.

Spotlight on latent tuberculosis infection screening for juvenile idiopathic arthritis in two countries, comparing high and low risk patients

Background

Rheumatic diseases are associated with an increase in overall risks of tuberculosis (TB). The aim of this study was to evaluate the frequency of TB and the frequency of latent TB infection (LTBI), in clinical practice, for juvenile idiopathic arthritis (JIA) patients from high and low risk of TB incidence endemic countries.

Methods

This is an international, multicenter, cross-sectional, observational study of data collection from Brazil and Registry of Portugal at REUMA.PT. The inclusion criteria were patients with Juvenile Idiopathic Arthritis (JIA) with age ≤ 18 years who underwent screening for Mycobacterium tuberculosis infection [tuberculin skin test (TST) and/or interferon gamma release assay (IGRA)]. Chest X-rays and history of exposure to TB were also assessed.

Results

292 JIA patients were included; mean age 14.3 years, mean disease duration 7.5 years, 194 patients (66.4%) performed only TST, 14 (4.8%) only IGRA and 84 (28.8%) both. The frequency of LTBI (10.6%) and TB was similar between the two countries. The reasons for TB screening were different; in Brazil it was performed more often at JIA onset while in Portugal it was performed when starting Disease Modified Anti-Rheumatic Drugs (DMARD) treatment (p < 0.001). Isoniazid therapy was prescribed in 40 (13.7%) patients (31 with LTBI and 9 with epidemiologic risks and/or due to contact with sick people). Only three patients (1%) developed active TB.

Conclusion

We found nearly 10% of patients with LTBI, a small percentage of patients with treatment due to epidemiologic risks and only 1% with active TB. Distinct reasons and screening methods for LTBI were observed between the two countries.

Takayasu arteritis in childhood: misdiagnoses at disease onset and associated diseases

Juvenile-Takayasu arteritis (j-TA) is a difficult diagnosis and some patients develop uncommon manifestations and associated diseases that may contribute to the delayed diagnosis. Our aim was to identify the misdiagnoses, the associated diseases and the atypical manifestations observed in a j-TA Brazilian multicentre study. 71 children and adolescents who met the classification criteria for j-TA were included. The misdiagnoses, the associated diseases and the atypical manifestations were evaluated. 19 (26.8%) patients had misdiagnoses. The most common of them was aortic coarctation in six (8.4%) patients, followed by rheumatic fever in five (7.0%) and one patient presented with both former diagnoses. Limb pain (two patients), spondyloarthropathy, juvenile idiopathic arthritis (JIA), spinal arteriovenous malformation, polyarteritis nodosa (PAN) and fever of unknown origin (FUO) were other misdiagnoses. Patients who had misdiagnoses previously to j-TA diagnosis presented a trend to have a longer diagnosis delay. 11 (15.5%) patients had 14 TA-associated diseases, such as pulmonary tuberculosis (5 patients), rheumatic fever (2 patients), spondyloarthropathy, polyarticular JIA, Crohn's disease, Prader-Willi disease, diabetes mellitus, Moyamoya and primary immunodeficiency. 7 (9.9%) patients presented 10 atypical manifestations, such as pyoderma gangrenosum, erythema nodosum, myositis, chorea, enthesitis, episcleritis, uveitis, hepatomegaly, splenomegaly and necrosis of extremities. Our study emphasizes the main misdiagnoses, associated diseases and atypical manifestations that occur in patients with j-TA and warns of the features that may alert paediatricians to this diagnosis, such as constitutional symptoms and elevated inflammatory markers.

Outcomes of 847 childhood-onset systemic lupus erythematosus patients in three age groups

Objective The objective of this study was to assess outcomes of childhood systemic lupus erythematosus (cSLE) in three different age groups evaluated at last visit: group A early-onset disease (<6 years), group B school age (≥6 and <12 years) and group C adolescent (≥12 and <18 years). Methods An observational cohort study was performed in ten pediatric rheumatology centers, including 847 cSLE patients. Results Group A had 39 (4%), B 395 (47%) and C 413 (49%). Median disease duration was significantly higher in group A compared to groups B and C (8.3 (0.1-23.4) vs 6.2 (0-17) vs 3.3 (0-14.6) years, p < 0.0001). The median Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR-DI) (0 (0-9) vs 0 (0-6) vs 0 (0-7), p = 0.065) was comparable in the three groups. Further analysis of organ/system damage revealed that frequencies of neuropsychiatric (21% vs 10% vs 7%, p = 0.007), skin (10% vs 1% vs 3%, p = 0.002) and peripheral vascular involvements (5% vs 3% vs 0.3%, p = 0.008) were more often observed in group A compared to groups B and C. Frequencies of severe cumulative lupus manifestations such as nephritis, thrombocytopenia, and autoimmune hemolytic anemia were similar in all groups ( p > 0.05). Mortality rate was significantly higher in group A compared to groups B and C (15% vs 10% vs 6%, p = 0.028). Out of 69 deaths, 33/69 (48%) occurred within the first two years after diagnosis. Infections accounted for 54/69 (78%) of the deaths and 38/54 (70%) had concomitant disease activity. Conclusions This large multicenter study provided evidence that early-onset cSLE group had distinct outcomes. This group was characterized by higher mortality rate and neuropsychiatric/vascular/skin organ damage in spite of comparable frequencies of severe cumulative lupus manifestations. We also identified that overall death in cSLE patients was an early event mainly attributed to infection associated with disease activity.

Levels and complexity of IgA antibody against oral bacteria in samples of human colostrum

Streptococcus mutans (SM) have three main virulence antigens: glucan binding protein B (gbpB), glucosyltransferase (Gtf) and antigens I/II (Ag I/II) envolved in the capacity of those bacteria to adhere and accumulate in the dental biofilm. Also, the glycosyltransferases 153 kDa of Streptococcus gordonii (SGO) and 170kDa of Streptococcus sanguinis (SSA) were important antigens associated with the accumulation of those bacterias. Streptococcus mitis (SMI) present IgA1 protease of 202 kDa. We investigated the specificity and levels IgA against those antigens of virulence in samples of human colostrum. This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the Western blot. The mean concentration of IgA was 2850.2 (±2567.2) mg/100 mL followed by IgM and IgG (respectively 321.8±90.3 and 88.3±51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

Efficacy of recombinant allergens for diagnosis of cockroach allergy in patients with asthma and/or rhinitis

BACKGROUND

Immunoglobulin E (IgE) reactivity to individual allergens among cockroach-allergic patients has revealed wide variability. The aim of this study was to assess the effectiveness of recombinant cockroach allergens for skin testing, and to determine sensitization profiles among cockroach-allergic patients living in Brazil.

METHODS

Fifty-seven cockroach-allergic patients with asthma and/or rhinitis were recruited. Skin testing with recombinant (r) allergens from Periplaneta americana (rPer a 1 and rPer a 7) and Blattella germanica (rBla g 2, rBla g 4 and rBla g 5) were performed at 10 μg/ml and 5 μg/ml (rPer a 1). IgE antibodies to rPer a 7 and rPer a 1 were quantitated by ELISA.

RESULTS

Of 57 patients tested, 3 (5.3%), 24 (42.1%), 4 (7%), 3 (5.3%) and 4 (7%) showed positive reactions to rPer a 1, rPer a 7, rBla g 2, rBla g 4 and rBla g 5, respectively. Twenty-eight patients (49.1%) had positive tests to at least one allergen. In keeping with skin test results, 31/57 patients (54.4%) and 5/55 patients (9%) had detectable IgE to rPer a 7 and rPer a 1, respectively. Levels of IgE to rPer a 7 were higher in patients with positive tests to rPer a 7 than those with negative tests (geometric mean 13.2 and 1.8 IU/ml, p < 0.05). There was good concordance of results of skin tests and measurements of serum IgE to rPer a 7.

CONCLUSION

IgE reactivity to rPer a 7 (P. americana tropomyosin) was dominant among patients in Brazil. However, 50% of the patients did not present reactivity to any of the recombinant allergens tested.

Prospective surveillance study of acute respiratory infections, influenza-like illness and seasonal influenza vaccine in a cohort of juvenile idiopathic arthritis patients

BACKGROUND

Acute respiratory infections (ARI) are frequent in children and complications can occur in patients with chronic diseases. We evaluated the frequency and impact of ARI and influenza-like illness (ILI) episodes on disease activity, and the immunogenicity and safety of influenza vaccine in a cohort of juvenile idiopathic arthritis (JIA) patients.

METHODS

SURVEILLANCE OF RESPIRATORY VIRUSES WAS CONDUCTED IN JIA PATIENTS DURING ARI SEASON (MARCH TO AUGUST) IN TWO CONSECUTIVE YEARS: 2007 (61 patients) and 2008 (63 patients). Patients with ARI or ILI had respiratory samples collected for virus detection by real time PCR. In 2008, 44 patients were immunized with influenza vaccine. JIA activity index (ACRPed30) was assessed during both surveillance periods. Influenza hemagglutination inhibition antibody titers were measured before and 30-40 days after vaccination.

RESULTS

During the study period 105 ARI episodes were reported and 26.6% of them were ILI. Of 33 samples collected, 60% were positive for at least one virus. Influenza and rhinovirus were the most frequently detected, in 30% of the samples. Of the 50 JIA flares observed, 20% were temporally associated to ARI. Influenza seroprotection rates were higher than 70% (91-100%) for all strains, and seroconversion rates exceeded 40% (74-93%). In general, response to influenza vaccine was not influenced by therapy or disease activity, but patients using anti-TNF alpha drugs presented lower seroconversion to H1N1 strain. No significant differences were found in ACRPed30 after vaccination and no patient reported ILI for 6 months after vaccination.

CONCLUSION

ARI episodes are relatively frequent in JIA patients and may have a role triggering JIA flares. Trivalent split influenza vaccine seems to be immunogenic and safe in JIA patients.

The PRINTO criteria for clinically inactive disease in juvenile dermatomyositis

OBJECTIVES

To develop data-driven criteria for clinically inactive disease on and off therapy for juvenile dermatomyositis (JDM).

METHODS

The Paediatric Rheumatology International Trials Organisation (PRINTO) database contains 275 patients with active JDM evaluated prospectively up to 24 months. Thirty-eight patients off therapy at 24 months were defined as clinically inactive and included in the reference group. These were compared with a random sample of 76 patients who had active disease at study baseline. Individual measures of muscle strength/endurance, muscle enzymes, physician's and parent's global disease activity/damage evaluations, inactive disease criteria derived from the literature and other ad hoc criteria were evaluated for sensitivity, specificity and Cohen's κ agreement.

RESULTS

The individual measures that best characterised inactive disease (sensitivity and specificity >0.8 and Cohen's κ >0.8) were manual muscle testing (MMT) ≥78, physician global assessment of muscle activity=0, physician global assessment of overall disease activity (PhyGloVAS) ≤0.2, Childhood Myositis Assessment Scale (CMAS) ≥48, Disease Activity Score ≤3 and Myositis Disease Activity Assessment Visual Analogue Scale ≤0.2. The best combination of variables to classify a patient as being in a state of inactive disease on or off therapy is at least three of four of the following criteria: creatine kinase ≤150, CMAS ≥48, MMT ≥78 and PhyGloVAS ≤0.2. After 24 months, 30/31 patients (96.8%) were inactive off therapy and 69/145 (47.6%) were inactive on therapy.

CONCLUSION

PRINTO established data-driven criteria with clearly evidence-based cut-off values to identify JDM patients with clinically inactive disease. These criteria can be used in clinical trials, in research and in clinical practice.

Vaccination practice in children with rheumatic disease

INTRODUCTION/OBJECTIVES

Evaluate clinical practice through assessment of vaccination card and recommendation of specific vaccines in pediatric patients with rheumatic diseases in use of different drugs and reveal the possible association between vaccination frequency and time of the clinical practice of pediatric rheumatologists in the state of São Paulo.

MATERIAL AND METHODS

A questionnaire was sent to pediatric rheumatologists of the Departamento de Reumatologia da Sociedade de Pediatria de São Paulo. This instrument included questions about practice time on Pediatric Rheumatology, vaccination of patients with juvenile systemic lupus erythematosus (JSLE), juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), and immunization according to the treatments used.

RESULTS

Vaccination card was seen by 100% of the professionals at the first visit and by 36% annually. Vaccines of live agents were not recommended for patients with JSLE, JIA, and JDM in 44%, 64%, and 48%, respectively. The professionals were divided into two groups: Group A (≤ 15 years of practice, n = 12) and B (≥ 16 years, n = 13). No statistical difference was observed in the use of live agent vaccine and vaccines with inactivated agents or protein components in the two treatment groups (P > 0.05). Moreover, the groups had similar opinion regarding severity of immunosuppression in patients with JSLE, JIA, and JDM (with or without activity) and treatment used (P > 0.05).

CONCLUSIONS

The frequency of immunization by pediatric rheumatologists in São Paulo is low, especially after the first visit, and not influenced by time of professional practice.

A Brazilian registry of juvenile dermatomyositis: onset features and classification of 189 cases

OBJECTIVE

To describe onset features, classification and treatment of juvenile dermatomyositis (JDM) and juvenile polymyositis (JPM) from a multicentre registry.

METHODS

Inclusion criteria were onset age lower than 18 years and a diagnosis of any idiopathic inflammatory myopathy (IIM) by attending physician. Bohan & Peter (1975) criteria categorisation was established by a scoring algorithm to define JDM and JPM based on clinical protocol data.

RESULTS

Of the 189 cases included, 178 were classified as JDM, 9 as JPM (19.8: 1) and 2 did not fit the criteria; 6.9% had features of chronic arthritis and connective tissue disease overlap. Diagnosis classification agreement occurred in 66.1%. Median onset age was 7 years, median follow-up duration was 3.6 years. Malignancy was described in 2 (1.1%) cases. Muscle weakness occurred in 95.8%; heliotrope rash 83.5%; Gottron plaques 83.1%; 92% had at least one abnormal muscle enzyme result. Muscle biopsy performed in 74.6% was abnormal in 91.5% and electromyogram performed in 39.2% resulted abnormal in 93.2%. Logistic regression analysis was done in 66 cases with all parameters assessed and only aldolase resulted significant, as independent variable for definite JDM (OR=5.4, 95%CI 1.2-24.4, p=0.03). Regarding treatment, 97.9% received steroids; 72% had in addition at least one: methotrexate (75.7%), hydroxychloroquine (64.7%), cyclosporine A (20.6%), IV immunoglobulin (20.6%), azathioprine (10.3%) or cyclophosphamide (9.6%). In this series 24.3% developed calcinosis and mortality rate was 4.2%.

CONCLUSION

Evaluation of predefined criteria set for a valid diagnosis indicated aldolase as the most important parameter associated with definite JDM category. In practice, prednisone-methotrexate combination was the most indicated treatment.

Is measurement of IgM and IgA rheumatoid factors (RF) in juvenile rheumatoid arthritis clinically useful?

The prevalence and clinical relevance of IgM and IgA RF detected by ELISA were studied in 91 patients with juvenile rheumatoid arthritis (JRA) and 45 healthy children. IgM and IgA RF were detected, respectively, in 33 and 44% of the patients, compared to 6.7 and 15.6% of the healthy children (p = 0.001 and 0.0006, respectively). The frequency of IgM RF was significantly higher in patients with polyarticular (52%) as compared to systemic onset JRA (21%; p = 0.04). Five out of ninety-one patients and none of the control group were IgM RF positive by the latex test. High levels of IgM RF were detected more frequently in patients with active disease (p = 0.01) and positive latex agglutination test (p < 0.001) and had a marginally significant association with severe radiological deformities (p = 0.05). The presence of IgA RF was associated with active disease in polyarticular onset JRA children (p = 0.04). In conclusion, high levels of IgM RF and the detection of IgA RF can be useful in assessing clinical activity in a subset of patients with JRA.

Risk factors for wheezing in a subtropical environment: role of respiratory viruses and allergen sensitization

Background

Risk factors for acute wheezing among children in subtropical areas are largely unknown.

Objective

To investigate the role of viral infections, allergen sensitization, and exposure to indoor allergens as risk factors for acute wheezing in children 0 to 12 years old.

Methods

One hundred thirty-two children 0 to 12 years of age who sought emergency department care for wheezing and 65 children with no history of wheezing were enrolled in this case-control study. Detection of respiratory syncytial virus antigen, rhinovirus and coronavirus RNA, adenovirus, influenza, and parainfluenza antigens was performed in nasal washes. Total IgE and specific IgE to mites, cockroach, cat, and dog were measured with the CAP system. Major allergens from mites, cockroach, cat, and dog were quantified in dust samples by ELISA. Univariate and multivariate analyses were performed by logistic regression.

Results

In children under 2 years of age, infection with respiratory viruses and family history of allergy were independently associated with wheezing (odds ratio, 15.5 and 4.2; P = .0001 and P = .008, respectively). Among children 2 to 12 years old, sensitization to inhalant allergens was the major risk factor for wheezing (odds ratio, 2.7; P = .03). High-level allergen exposure, exposure to tobacco smoke, and lack of breast-feeding showed no association with wheezing.

Conclusions

Some risk factors for wheezing previously identified in temperate climates were present in a subtropical area, including respiratory syncytial virus infection in infants and allergy in children older than 2 years. Rhinovirus was not associated with wheezing and did not appear to be a trigger for asthma exacerbations.

Determination of CD59 protein in normal human serum by enzyme immunoassay, using octyl-glucoside detergent to release glycosyl-phosphatidylinositol-CD59 from lipid complex

In this study we have optimised the enzyme immunoassay (ELISA) to quantify CD59 antigen in human serum or plasma. The glycosyl-phosphatidylinositol (GPI)-linked form of CD59 is known to complex with serum high-density lipoprotein. For ELISA optimisation, therefore, we investigated the effect of detergents, added to the sample diluent, on the determined values of CD59. Values obtained in the presence of octyl-glucoside (OG) for 20 adults aged 18-35 years and 17 children 1-5 years old were, respectively, 33-119 ng/ml (mean +/- S.D.: 66+/-22 ng/ml) and 37-143 ng/ml (76+/-33 ng/ml). These results were higher than those measured without OG and were in contrast with published results showing absence, or eight to nine times lower levels, of the protein in serum. A known range for serum concentrations of CD59 in healthy individuals will establish an important reference point for clinical work and for the investigation of diseases involving the complement membrane attack complex (MAC) and its regulation.

Exposure to indoor allergens in homes of patients with asthma and/or rhinitis in southeast Brazil: effect of mattress and pillow covers on mite allergen levels

BACKGROUND

Exposure and sensitization to indoor allergens have been associated with the development of asthma and other allergic diseases in many parts of the world. It is important to establish the degree of exposure, and to evaluate whether allergen control measures are effective in a particular area.

METHODS

Concentrations of major allergens of mites, cockroach, cat and dog were measured in dust samples from homes of 24 mite-allergic patients living in Ribeirão Preto, Brazil. Allergen concentrations were quantitated by monoclonal antibody-based ELISA. Mite-impermeable mattress and pillow covers were applied to beds in the homes of 19 of the 24 patients, and group 1 mite allergen levels were measured 1 and 6 months following intervention.

RESULTS

Patients were exposed to high concentrations of mite allergens in their homes. 87.5% of the homes presented concentrations of group 1 allergens >10 microg/g of dust in at least one site. Cockroach allergen concentrations were low in most samples. Dog allergen concentrations were significantly higher in homes with dogs as compared to those without dogs. Mean concentrations of cat allergen were 0.1 microg/g. Mite allergen concentrations in bedding samples dropped from 24 microg/g at baseline to 0.9 and 1.0 microg/g, respectively, 1 and 6 months following encasement of mattresses and pillows.

CONCLUSIONS

Significant mite allergen reduction can be achieved in an area of high degree of exposure to mite allergens. Further studies evaluating the effect of this reduction on symptoms and airway inflammation will be necessary to establish the effectiveness of mite avoidance measures in our area.

Ontogeny of complement regulatory proteins - concentrations of factor h, factor I, c4b-binding protein, properdin and vitronectin in healthy children of different ages and in adults

Previous studies of human in vivo complement protein levels have only compared data for neonates with that from adult sera. Here, we establish the normal concentration ranges of the following complement regulatory proteins in healthy Brazilian children of different age groups (neonates: 1 month-1 year, 1-6 years and 6-13 years) and in adults: factor H (fH), factor I (fI), C4b-binding protein (C4 BP), properdin and vitronectin. We found that the concentrations of fH, fI, properdin and vitronectin in neonates are significantly lower than in adults. Remarkably, the concentration of C4 BP is below the method resolution (<50 micro g/ml) in 76% of the sera from neonates, while adults presented 199-532 microg/ml of C4 BP in their sera. The concentration of properdin in the sera from neonates and up to 1-year-old children was less than that observed in older children. Adults presented vitronectin levels significantly higher than all the other age groups in the study. No significant sex differences in the concentrations of all the studied regulatory proteins were detected. This study reveals the ontogeny of complement system in greater detail than previously available and may point to the reasons why neonates have higher susceptibility to develop life-threatening pyogenic infections. These reference values will be of use in clinical and laboratory investigations of disorders associated with low levels of these regulatory proteins.

[Health related quality of life survey about children and adolescents with juvenile idiopathic arthritis]

OBJECTIVE

To study the impact of chronic arthritis on health related quality of life by means of two self-reported tools: the parents' version of the Childhood Health Assessment Questionnaire (CHAQ) and the Childhood Health Questionnaire PF50\'ae (CHQ).\par

METHODS

Both tools were filled in after proper instructions by 36 parents, during 1-2 clinic visits. The Disability Index (CHAQ) and the Physical and Psychosocial scores (CHQ) were compared to the core set of outcome measures, namely 1) physician's global assessment, 2) parents' global assessment, both scored by 10 cm visual analogue scale, 3) number of joints with active arthritis, 4) number of joints with limited range of motion, 5) erythrocyte sedimentation rate.\par

RESULTS

There was significant difference for all measures of disease activity, being higher in the polyarticular as compared to oligoarticular except for erythrocyte sedimentation rate, parents' global assessment, and psychosocial score. This leads to different parents' perceptions of disease activity and outcome. The responsiveness of the outcome measures during two follow-up visits of patients receiving active treatment indicated better responsiveness of physicians' global assessment among the subjective measures, and intermediate responsiveness of the self-reported measures in comparison to the number of active and limited joints, and erythrocyte sedimentation rate. \par

CONCLUSIONS

The responsiveness of two health related quality of life tools indicates their relative sensitivity for assessing clinical improvement during active treatment in Juvenile Idiopathic Arthritis patients.\par

Use of a chimeric ELISA to investigate immunoglobulin E antibody responses to Der p 1 and Der p 2 in mite-allergic patients with asthma, wheezing and/or rhinitis

BACKGROUND

Sensitization to indoor allergens, particularly to dust mites, is a strong risk factor for asthma in children and adults. Assessment of sensitization is carried out using in vivo and in vitro tests to detect specific IgE antibodies.

OBJECTIVE

To investigate IgE antibody responses to mites in patients with asthma, wheezing and/or rhinitis, using chimeric ELISA to measure specific IgE antibodies to mite allergens Der p 1 and Der p 2.

METHODS

Specific IgE antibodies to Der p 1 and Der p 2 were quantified by chimeric ELISA, and compared with IgE to Dermatophagoides pteronyssinus (Dpt) measured using the CAP system (Pharmacia). A panel of sera from 212 patients with asthma, wheezing and/or rhinitis and 11 controls was analysed.

RESULTS

There was a significant correlation between IgE to Dpt measured by CAP and IgE to Der p 1 (r = 0.81, P < 0.001), Der p 2 (r = 0.79, P < 0.001) and combined Der p 1 and Der p 2 (r = 0.86, P < 0.001). Seventy per cent of all patients had IgE to Dpt, and of those, 76.5% had IgE to Der p 1, 79.2% had IgE to Der p 2 and 83.1% had IgE to Der p 1 and Der p 2 combined. Considering the cut-off level of 2 IU/mL of IgE to either Der p 1 or Der p 2, the predictive value for a positive IgE to Dpt by CAP was greater than 95%.

CONCLUSIONS

The chimeric ELISA allowed accurate quantification of IgE antibodies to Dpt allergens Der p 1 and Der p 2, and it could be useful for studying immune responses to mites in patients with asthma and/or rhinitis.