Pilot study of etanercept in patients with refractory juvenile dermatomyositis.

OBJECTIVE: To evaluate the efficacy of etanercept in patients with juvenile dermatomyositis (DM) refractory to standard treatment. METHODS: Nine patients with juvenile DM prospectively received etanercept 0.4 mg/kg subcutaneous twice weekly concurrently with baseline medications for 12 weeks. Patients were reevaluated 12 weeks (week 24) after stopping etanercept. Outcome measures included a validated Disease Activity Score (DAS), serum muscle enzymes, Childhood Myositis Assessment Scale (CMAS), and nailfold capillaroscopy (NFC). RESULTS: Six patients completed all visits; 2 patients completed through week 12 and 1 patient stopped after the fifth etanercept dose due to marked worsening of a rash. At week 12, 7 patients had a mild decrease in DAS and 1 patient noted worsening of the DAS. At week 24, 1 patient remained stable, 2 patients had worsening of the DAS, and 3 patients had improvement of the DAS (1 patient with inactive disease), including the patient who worsened while receiving etanercept. This patient and the patient who stopped (worsening rash) both had the tumor necrosis factor α (TNFα) 308A allele. There was a trend of worsening NFC at week 12, while at week 24 improvement of NFC was noted. There was no appreciable change in serum muscle enzymes or CMAS throughout the study. CONCLUSION: In this trial of patients with refractory juvenile DM, etanercept did not demonstrate appreciable improvement and some patients noted worsening of disease. Caution should be taken when recommending TNF receptor inhibitors to patients with active symptoms of juvenile DM, and close followup is warranted. Further investigation of the interaction of the TNFα-308A polymorphism and type I interferon is needed to define the mechanism of TNF blockade in juvenile DM.

Pulmonary function tests in idiopathic inflammatory myopathy: association with clinical parameters in children.

OBJECTIVE: To determine the association of decreased lung function in children with idiopathic inflammatory myopathies (IIMs) with specific clinical parameters. METHODS: This study of 38 children ages 6-23 years diagnosed with definite/probable IIM evaluated the association of myositis-specific/-associated antibodies (MSAs/MAAs), duration of untreated disease at diagnosis, Disease Activity Score for muscle (DAS-M), muscle-derived enzymes (aldolase, lactate dehydrogenase [LDH], aspartate transaminase, and creatine phosphokinase [CPK]), neopterin and von Willebrand factor antigen, and the Childhood Myositis Assessment Scale (CMAS) scores with data from pulmonary function testing (PFT). RESULTS: Impaired PFTs were defined as total lung capacity (TLC) or diffusing capacity for carbon monoxide (DLCO) of <80% predicted. The PFTs documented that 37% of the children (14 of 38) had either decreased TLC or decreased DLCO; 5% (2 of 38) had both. Children with decreased TLC alone (7 [18%] of 38) were older both at the time of PFT and diagnosis, had anti-Jo-1 and anti-Scl-70 antibody, and had elevated levels of CPK and neopterin. Children with decreased DLCO alone (5 [13%] of 38) had a shorter duration of untreated disease at diagnosis, had higher DAS-M and total DAS, were positive for anti-Ro and anti-PL-12, had increased LDH, and had elevated levels of neopterin and aldolase, with low CMAS scores for items 1, 3, 10, 11, and 14. CONCLUSION: Assessment of PFTs in children with IIMs should be considered, since more than one-third of patients were found to be impaired. The presence of MSAs/MAAs, an elevated serum neopterin level (mean ± SD 12.4 ± 9.6 nmoles/liter, normal value <10.5), older age at diagnosis, and shorter duration of untreated disease at diagnosis suggest the presence of potential lung pathology.