Table 3

Muscle pathology in immune myopathies: comparative features

Anti-SRP myopathyPolymyositis: Jo-1 antibody positivePolymyositis: Jo-1 antibody negativeDermatomyositisFasciitisParaneoplastic necrotic myopathy
*Based on six rather than seven anti-SRP patients: one muscle biopsy (from patient No 2) had too few muscle fibres for determination of the capillary index.
aDifferent from other forms of immune myopathy, p < 0.001.
bDifferent from myositis and fasciitis, p < 0.001.
cDifferent from dermatomyositis, p < 0.001.
dDifferent from Jo-1 myositis and fasciitis, p < 0.001.
eDifferent from polymyositis and fasciitis, p < 0.001.
ND, not determined; +, positive.
No of biopsies7118854
Inflammation (focal)2a118650
    Perimysial0113150
    Endomysial224300
    Perivascular115420
Muscle fibre features
    Enlarged muscle fibres6*a00000
    Perifascicular myopathy0 c110810
    Regional necrosis000004
Perimysium
    Fragmentation1d111030
    Alkaline phosphatase +3103212
Endomysium
    Diffusely increased6a00000
Vessels
    Reduced number4*b00700
    Enlarged size6*b00600
    C5b-9 deposition7e00502