Background JDM has distinct clinical, immunologic and pathological features compared with patients of adult onset. Studies have evidenced Fas, Fas ligand (FasL), TNF related apoptosis inducing ligand (TRAIL) and Bcl-2 altered expressions in both muscle fibers and inflammatory cells in biopsies from adult and juvenile dermatomyositis.1-5 The role of soluble apoptosis molecules in JDM is not yet defined.
Objectives This study assessed soluble Fas, FasL, TRAIL and Bcl-2 in JDM patients and evaluated the relation with disease activity markers.
Methods sFas, sFasL, sTRAIL and sBcl-2 levels were measured in sera from 34 JDM patients (22 girls, mean age 10.8 yrs, Bohan and Peter criteria), 40 gender and age matched healthy individuals (26 girls, mean age 10.7 yrs), 33 JIA patients (20 girls, mean age 11.9 yrs) and 41 JSLE patients (20 girls, mean age 12.2 yrs) as disease controls. Soluble apoptosis molecules were quantified by commercial ELISA Kits following manufacturer's instructions. Disease activity markers included ERS (Westergreen), CRP (nephelometry), CMAS and MMT. Statistical analysis used nonparametric Kruskal-Wallis test and Spearman's rank. P-values<0.05 were considered significant.
Results JDM patients presented significant increased sBcl-2 levels compared with healthy controls which negatively correlated with CRP (r=0.55; p=0.01). sFas and sTRAIL were similar to controls and sFasL was detected in only one patient (0.32 ng/ml). JIA patients had sFas, sFasL, sTRAIL and sBcl-2 similar to healthy controls. In contrast, JSLE patients had increased sFas and sTRAIL, decreased sFasL and similar sBcl-2 levels compared with controls (Table).
Conclusions JDM patients presented a unique profile of soluble apoptosis molecules characterized by increased sBcl-2 levels, contrasting with the results of adult patients that had increased sFas, and similar sFasL levels.6,7 This particular profile may contribute to disease pathogenesis and is distinct from those presented by JIA and JSLE patients.
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Acknowledgements We thank FAPESP (grants 2012/22997-4 and 2008/58238-4) for supporting this study.
Disclosure of Interest None declared