Wedderburn et al reported a scoring system for evaluating muscle biopsies from a patient with juvenile dermatomyositis. This consists of 4 domains and a visual analogus scale (VAS).
Patient selection: juvenile dermatomyositis
Parameters for the inflammatory domain:
(1) CD3+ endomysial infiltration
(2) CD3+ perimysial infiltration
(3) CD3+ perivascular infiltration
(4) CD68+ endomysial infiltration
(5) CD68+ perimysial infiltration
(6) CD68+ pervascular infiltration
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Finding
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Points
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< 4 positive cells per hpf (20x objective)
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0
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>= 4 positive cells per hpf (20x objective)
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1
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1 cluster with 10+ positive cells
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1
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> 2 clusters with 10+ positive cells in entire biopsy
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2
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diffuse infiltration
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2
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subscore for inflammatory domain =
= SUM(points for all of the parameters)
Parameters of the vascular domain:
(1) capillary dropout on a stain for CD31: obvious and marked decrease in the density of the capillary network, not restricted to the areas of perifascicular atrophy
(2) arterial abnormality: mural thickening and/or endothelial swelling and/or transmural inflammation
(3) infarction: well-demarcated regional loss of muscle fiber nuclei and loss of normal cellular architecture
subscore for vascular domain =
= (number of items present)
Interpretation:
• minimum subscores: 0
• maximum inflammatory subscore: 12
• maximum number of vascular items: 3
