Abstract
Objective Myositis-specific antibodies (MSAs) facilitate grouping children with juvenile dermatomyositis (DM) into distinct phenotypes. The first aim of this study was to investigate the link between anti-p155/140 and lipodystrophy as determined by dual x-ray absorptiometry (DXA) assessment of fat distribution. The second aim was to examine the relationship between anti-p155/140 and damage to the nailfold capillary system. Methods Children with juvenile DM followed for a minimum of 5 years were included. The study population was divided into 3 groups (anti-p155/140, other MSA, and MSA negative). Lipodystrophy was assessed by physician assessment and DXA fat distribution (trunk-to-leg fat ratio). Documentation of nailfold capillary end row loops (ERLs) was obtained at diagnosis. Results A total of 96 subjects (44% anti-p155/140, 23% other MSA, 33% MSA negative) were included. There was no significant difference in age, disease activity scores, or lipodystrophy between the 3 groups. The trunk-to-leg fat ratios were similar among the 3 groups at different time points. However, the anti-p155/140 group had significantly decreased ERL counts (P = 0.006) at baseline as well as a prolonged duration of untreated disease at diagnosis (P = 0.027). Also, the anti-p155/140 group had fewer patients with a monophasic disease course than the other 2 groups (P = 0.008). Conclusion Generalized lipodystrophy frequency was equivalent in all 3 groups based on physician assessments and trunk-to-leg fat ratios. The anti-p155/140 group had a greater loss of ERLs, suggesting that this MSA may impact the vascular component of juvenile DM.