Review on IVIG Therapy in Dermatomyositis: Can the MAC Pathway Be Suppressed?
Melissa Payne
Abstract
Myositis encompasses different idiopathic inflammatory myopathies (IIMs) which contain a subset of diseases that are regulated through an irregular autoimmune response. A rare form of IIM is Dermatomyositis. Dermatomyositis is mediated by a complement process that results in the destruction of muscle fibers through the membrane attack complex (MAC). When dermatomyositis patients become resistant to fist-line interventions, there is an inadequate response in the patients’ health which leads to physical disabilities. When first-line therapies provide insufficient remission states, second-line therapies are administered or paired with the first-line drugs. Intravenous immunoglobulin (IVIG) is an immune-modulating therapy introduced as a second line therapy; it affects the immune system at multiple levels. In dermatomyositis, IVIG therapy has been shown to diminish the formation of MAC depositions through inhibiting the assembly of C5B-9 B cells on capillaries and muscle fibers. Inhibition of MAC through the Fc receptor on IgG antibodies disrupts multiple polymerization steps through the complement pathway. The impact IVIG has on dermatomyositis exhibits significant impacts on muscle strength and skin lesions, improving and prolonging remission states seen in dermatomyositis patients.
