MYOSITIS PROFILE, SERUM
(Immunoblot)
Mi-2
Ku
PM-Scl 100
PM-Scl 75
Jo-1
SRP
PL-7
PL-12
EJ
OJ
Ro-52
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Note
All results must be correlated with ANA screening by Indirect Immunofluorescence assay
Comment
Myositis is an inflammatory disease of the skeletal muscle which may be hereditary or caused by
infection, autoimmunity or toxins. The detection of Myositis associated antibodies is essential in the
diagnosis of Dermatomyositis / Polymyositis in monitoring the course of disease & therapy
management.
AUTO
ANTIBODY
Mi-2
Prevalence (%)
REMARKS
15-30
Ku
10
PM Scl
(PM-1)
50-70
Highly specific for Dematomyositis; may also be seen in Idiopathic
Myositis
Systemic Lupus Erythematosus (SLE), Systemic Sclerosis (SSc)
40% of symptoms in patients with antibodies to Ku are Myositis
related
Overlap syndrome (Combination of Polymyositis, Dermatomyositis
& Systemic Sclerosis)
Jo-1
25-55
Polymyositis
PL-7
3-6
PL-12
3
Polymyositis, partly overlapping with SLE, SSc or Interstitial lung
fibrosis
Myositis