Table 2

Muscle pathology in patients with anti-SRP antibodies

Patient No
NA, tissue type not present for evaluation in biopsy; +, present in biopsy; −, not present in biopsy.
Time from disease onset to muscle biopsy (months)536381032
Pathological features
Lymphocytic inflammation
Muscle fibre size
    Hypercontracted fibres+NA+
    Grouped small round fibres+NA+++++
    Perifascicular atrophyNA
Muscle fibre pathology
        Regional (large groups)NA
    Coarse internal architecture+NA+++++
    Immature (2C) fibres+NA++++
    Mitochondrial changesNA
    C5b-9 deposition±NA
Connective tissue features
        Acid phosphatase+/CD68+ cells+NA+++++
        Alkaline phosphatase staining+++
        Acid phosphatase+/CD68+ cells++
        Reduced number+NA+++
        Enlarged size+NA+++++
C5b-9 deposition+++++++