Key messages

• Intravenous immunoglobulin — a treatment made from donor antibodies — may slightly improve symptoms and the ability to carry out daily activities in people with myasthenia gravis, a disease in which the immune system — the body’s defenses — attacks the communication between nerves and muscles, causing weakness. However, the effects may not be large enough to matter to patients.

• Compared to plasma exchange — a procedure that filters harmful antibodies from the blood — intravenous immunoglobulin may be less beneficial in improving symptoms and may prolong hospital stay, but we are not confident in the evidence for these results.

• Intravenous immunoglobulin probably causes headache in up to one-third of patients and may lead to the breakdown of red blood cells, though it is unclear whether this would make a real difference to patients’ health.

• For many results, we have little or no confidence in the evidence due to limited data and study quality, highlighting the need for further well‑designed studies.

What is myasthenia gravis?

Myasthenia gravis is a rare disease where the immune system attacks the communication between nerves and muscles, causing weakness. It often affects the muscles used for eye movement, facial expressions, and swallowing, which can reduce quality of life and, in some cases, increase the risk of death.

How is myasthenia gravis treated?

Treatment for myasthenia gravis is personalized and often begins with medicines which help nerves send signals to muscles more effectively. Other treatments may include medicines that reduce the immune system’s activity, targeted immune treatments, surgical removal of the thymus gland, plasma exchange, or immunoglobulin.

What did we want to find out?

We wanted to find out if immunoglobulin given through a vein (called intravenous immunoglobulin, or IVIg) or under the skin (called subcutaneous immunoglobulin) provides more benefit than other treatments, such as plasma exchange, corticosteroids, or placebo (a dummy treatment), in reducing physician-assessed disease symptoms, and improving patients' ability to carry out daily activities. We also investigated whether immunoglobulin affects length of hospital stay, leads to myasthenia gravis-related hospitalizations, and causes specific treatment-related unwanted effects, such as hypotension (low blood pressure), headache or breakdown of red blood cells.

What did we do?

We searched for studies comparing immunoglobulin to other treatments in people who still had symptoms despite receiving other therapies, including only those that randomly assigned people to treatment groups.

We compared and summarized the study results and rated our confidence in the evidence, based on factors such as study methods and sizes.

What did we find?

We included 12 studies with 515 people conducted in Europe, North America, and Asia between 1997 and 2025. All studies evaluated IVIg; no studies evaluated subcutaneous immunoglobulin.

• IVIg versus placebo: IVIg may slightly improve physician-assessed symptoms and self-reported ability to carry out daily activities for up to six months, though the effects may not be large enough to matter to patients, but we have little confidence in the evidence. We are moderately confident that IVIg probably causes headache in up to one-third of patients. It may lead to the breakdown of red blood cells, though it is unclear whether this would make a real difference to patients’ health, and we have little confidence in the evidence. IVIg may not change the length of hospital stay, but we are not confident in the evidence for this. It may also not lead to more myasthenia gravis‑related hospitalizations, but again, we have little confidence in the evidence.

• IVIg versus plasma exchange: IVIg may be less beneficial than plasma exchange in improving physician-assessed symptoms, but both treatments may improve self-reported ability to carry out daily activities to a similar degree in the first two weeks. However, we are not confident in the evidence for these results. IVIg may also lead to longer hospital stays than plasma exchange, but we have little confidence in the evidence. The two treatments may not differ in their unwanted effects, but again, we are not confident in the evidence.

• IVIg versus corticosteroids: IVIg and corticosteroids may not differ in physician-assessed symptom improvement in the first two weeks, but we are not confident in the evidence. No evidence was available for other outcomes.

• IVIg versus subcutaneous immunoglobulin: no studies evaluated subcutaneous immunoglobulin or compared it to IVIg or other treatments.

What are the limitations of the evidence?

Our confidence in the evidence was reduced due to limited data, concerns about how people were assigned to treatments, and because many outcomes were only reported by one study. There was no evidence evaluating subcutaneous immunoglobulin or its comparison to IVIg or plasma exchange. We also found no usable data for many outcomes we had planned to study.

How up to date is this evidence?

The review is up to date as of September 2024.