From the Guidelines
Intravenous Immunoglobulin (IVIG) is recommended as a second-line therapy for early myositis, particularly in patients with severe or rapidly progressive disease, those with dysphagia or respiratory involvement, and individuals who cannot tolerate standard immunosuppressive therapies due to side effects or comorbidities, with a typical dosing regimen of 1-2 g/kg of ideal body weight, usually given over 2 consecutive days, once a month for 1 to 6 months, as supported by the most recent evidence from 1.
The use of IVIG in myositis is based on its immunomodulatory effects, including neutralization of pathogenic autoantibodies, inhibition of complement activation, modulation of cytokine production, and regulation of T-cell and B-cell function, which help reduce muscle inflammation and promote recovery of muscle strength.
Some key points to consider when using IVIG in myositis include:
- Monitoring treatment response through clinical strength assessments, creatine kinase levels, and functional outcome measures
- Using IVIG cautiously in patients with renal insufficiency, thrombotic risk factors, or IgA deficiency
- Considering the use of IVIG in combination with other immunosuppressive therapies, such as corticosteroids and synthetic or biologic disease-modifying antirheumatic drugs, as supported by evidence from 1 and 1
- Being aware of the potential side effects of IVIG, including headache, fever, nausea, and infusion reactions, which can be minimized by slowing the infusion rate and providing premedication with acetaminophen and antihistamines.
Overall, the decision to use IVIG in myositis should be based on a careful assessment of the individual patient's needs and circumstances, taking into account the potential benefits and risks of this therapy, as well as the availability of other treatment options, as discussed in 1, 1, and 1.
From the Research
Role of IVIG in Early Myositis Treatment
- IVIG has been shown to be an effective treatment for polymyositis and dermatomyositis, with significant clinical improvement noted in 15 of 20 patients in one study 2.
- The use of IVIG in the treatment of inclusion-body myositis has also been reported, with improvement in strength of proximal and less atrophic muscle groups in three of four patients 3.
- In cases of refractory myositis, such as immune-mediated necrotizing myopathy, intensive treatment involving the addition of immunosuppressive agents and repeated intravenous administration of immunoglobulin therapy is recommended 4.
Benefits of Early IVIG Initiation
- Early initiation of IVIG treatment has been shown to be beneficial in patients with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase immune-mediated necrotizing myopathy, with significant improvement in manual muscle testing and limited total improvement score 5.
- Delay in IVIG treatment may lead to the development of permanent residual weakness and long-term disability 5.
IVIG Therapy in Adult Patients with Polymyositis/Dermatomyositis
- A systematic literature review found that IVIG therapy is effective in the treatment of adult patients with polymyositis/dermatomyositis, with a standard dose of 2 g/kg given in two to five individual daily doses 6.
- IVIG therapy has been shown to be effective in patients with refractory, flare-up, rapidly progressive, or severe polymyositis/dermatomyositis, and can be tried in patients with a contraindication for corticosteroid 6.