OBJECTIVE
Myositis-specific antibodies (MSA) facilitate grouping children with Juvenile Dermatomyositis (JDM) into distinct phenotypes. Aim one of this study investigates the link between anti-P155/140 and lipodystrophy as determined by DXA assessment of fat distribution. Aim two examines the relationship between anti-P155/140 and damage to the nailfold capillary system.
METHODS
Children with JDM followed for a minimum of five years were included. The study population was divided into three groups (anti-P155/140, other MSA, and MSA negative). Lipodystrophy was assessed by physician assessment and DXA fat distribution (Trunk:Leg fat ratio). Documentation of nailfold capillary end-row loops (ERL) was obtained at diagnosis RESULTS: 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 three groups. The Trunk:Leg fat ratios were similar among the three groups at different time points. However, the anti-P155/140 group had significantly decreased (ERL) count (p-value = 0.006) at baseline as well as a prolonged duration of untreated disease at diagnosis (p-value = 0.027). Also, the anti-P155/140 group has fewer patients with monophasic disease course than the other two groups (p-value = 0.008) CONCLUSIONS: Generalized lipodystrophy frequency was equivalent in all three groups based on physician assessments and Trunk:Leg fat ratios. The anti-P155/140 group had a greater loss of ERL, suggesting that this MSA may impact the vascular component of JDM.