context: This therapy can help people with weakened immune systems or other diseases fight off infections. Some of the diseases that intravenous immunoglobulin ( IVIg) can treat include: Immune deficiencies like immune thrombocytopenia Kawasaki disease Guillain- Barre syndrome Chronic inflammatory demyelinating polyneuropathy Lupus Myositis Other rare diseases Neurological diseases like myasthenia gravis or multiple sclerosis People who receive bone marrow transplants may also use IVIg to prevent infections. Some people may take IVIg instead of other medications (such as immunosuppressants, corticosteroids, or biologic drugs) to help treat their immune system disorders. In some cases, you may take IVIg along with immunosuppressants or other meds. Your body's immune system normally makes enough antibodies to fight germs that cause infections. But if you have an immune deficiency, your body can't make enough of them. This puts you at greater risk for infections that could make you very sick. IVIg gives you antibodies that your body is not making on its own so you can fight infections. In autoimmune diseases like lupus, the treatment may help your body raise low red-blood-cell counts. Not enough of these and you can become anemic and feel very tired. IVIg helps stop the white blood cells of people with lupus from destroying their red blood cells. In people with myositis, the treatment may block your immune system's destruction of muscle cells. Both children and adults can have this therapy. Immunoglobulin is part of your blood's plasma. It has antibodies in it to fight germs or disease. When people donate blood, this part can be separated out. Then it can be given to you through a vein in your arm, or IV. If you get IVIg, it can help strengthen your immune system so you can fight infections and stay healthy. Liquid immunoglobulin is taken from the blood plasma of donors who are screened to make sure they are healthy. The plasma is tested for serious infections like hepatitis and AIDS. The plasma is purified before it's used for IVIg therapy. During the therapy, prepared immunoglobulin is infused into your veins. A health care provider uses a needle to get into your vein. Then the medicine can flow from a bag through a tube into your arm. This takes about 2 to 4 hours. You'll probably go to an infusion center, hospital, clinic, or doctor's office to get the treatment. Sometimes you can have treatments done at your home by a medical professional. Typically you'll have treatments every 3 to 4 weeks to keep your immune system strong. Your blood may break down about half of the immunoglobulin over that period, so you'll need another dose to keep fighting infections. Your IVIg dosage depends on how much you weigh. The standard starting dosage is 400 to 600 mg/kg of your body weight per month. Most people tolerate IVIg well, but side effects can include low-grade fever, muscle or joint aches, and headaches just after your infusion. Call your doctor if you have a headache that doesn't get better after taking medicines. Get emergency medical help right away if you get hives, a tight feeling in your chest, or you wheeze. You might feel your best soon after your treatment, when the highest amount of immunoglobulin is in your body. As your body absorbs it , though, you may start to feel more weak or tired. You might feel your worst just before your next treatment. If you have severe side effects from IVIg, you might be able to switch to another type of treatment called subcutaneous immunoglobulin therapy, or SCIG. You'd get shots with small amounts of immunoglobulin under your skin either once a week or every few days. Talk to your doctor about your treatment options.