Some of these additional tests may include a WBC differential, a blood smear review, or in severe conditions, a bone marrow examination. A differential may indicate which type of WBC is low or high while a blood smear and/or bone marrow biopsy can reveal the presence of abnormal and/or immature WBCs. ^ Back to top.
The most common types are dermatomyositis, polymyositis, necrotising autoimmune myopathy and sporadic inclusion body myositis (IBM). Although dermatomyositis affects the skin and muscles, it may also affect other parts of the body such as joints, oesophagus, lungs and heart.
Polymyositis is an inflammatory disease of muscles, causing weakness in the muscles closest to the torso -- usually the shoulder and hip muscles. It is an autoimmune disorder, meaning that a person's white blood cells begin attacking muscles for an unknown reason.