Predictor of Clinical Response to Acthar in Myositis

To compare the clinical impact of Acthar Gel at the cellular and molecular level before and after treatment and compare it to patients with inactive disease. The cohort of active myositis subjects are not actually enrolled in this study, but rather the data for those with active myositis will be obtained from a previously completed trial entitled "Efficacy and safety of Adenocorticotropic Hormone Gel in Refractory dermatomyositis and polymyositis".

Inclusion criteria

• Healthy Controls:

• An individual will be eligible to be a control subject if his/her age is 18 years or greater.
• Myositis Remission Control Group

• Definite or probable PM or DM by Bohan and Peter criteria.
• PM patients must either possess a myositis-associated autoantibody or undergo adjudication for confirmation of the PM diagnosis by consensus of two experts (Aggarwal or Oddis) to ensure non-PM patients are not enrolled. This step is necessary since there are well known mimics of PM.
• Age is greater than or equal to 18 years
• Remission of myositis as defined by a myositis disease global activity score <1 on the MDAAT and no new immunosuppressive or glucocorticoid therapy or dose change within one year.

Exclusion criteria

• Healthy Controls:

• An existing diagnosis of a CTD
• A potential immune compromised state, for example, treatment with immunosuppressant or anti-rejection medication or a diagnosis of an immune deficiency disease
• Myositis Remission Control Group:

• Juvenile DM or PM, myositis in overlap with another connective tissue disease, cancer associated myositis, inclusion body myositis, or any other non immune mediated myopathy.
• Severe muscle damage defined as a baseline global muscle damage score on the MDI (Myositis Damage Index) of greater than or equal to five centimeters on a ten centimeter VAS.
• Patients with malignancy within three years of screening (except basal cell cancer or squamous cell cancer of skin.
• Uncontrolled diabetes, hepatic or renal disease.