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.