What is IVIg, where does it come from and why is it used in KD?
Immunoglobulins are antibodies, and part of the immune system. In health, their main role is to help fight infections.
Immunoglobulins are collected from plasma – the liquid part of the blood – donated by blood donors.
Immunoglobulins can be used for treatment of a wide range of conditions. In some people with low immunoglobulin levels, replacing immunoglobulins to normal levels can reduce the risk of infection. These treatments may be administered either intravenously (through a vein) or subcutaneously (under the skin).
High-dose intravenous immunoglobulins (IVIg) can also be effective treatment for many other conditions, including some with inflammatory, immune, or infectious causes, or where the underlying cause is not known.
Kawasaki Disease is one of these conditions and IVIg is a mainstay of current therapy. Under the National Blood Authority Criteria, treatment of KD is approved for access to government-funded immunoglobulin therapy, at no direct charge to the patient.
Currently there is no synthetic (artificial) alternative to plasma-derived IVIg, and thousands of plasma donations need to be processed to make one batch. Clinical demand is growing, and Australia now imports over half the immunoglobulins we use. IVIg products are also very costly, in part reflecting the many steps required for their production and to make sure they are as safe as possible. These include careful blood donor selection, testing of donated plasma, treatment of the plasma and the final product during preparation to reduce infectious and other risks, and careful documentation of all steps in the process.
Ongoing supply of plasma is essential to make sure that there is enough IVIg for patients who need it. In Australia, you can check if you are eligible to donate plasma at: https://www.lifeblood.com.au/donors/blood-plasma-platelets/making-a-donation
More information on how immunoglobulins are managed in Australia is available here:
https://www.blood.gov.au/immunoglobulin-therapy
and a useful video is available here:
https://www.blood.gov.au/immunoglobulin-videos-clinicians-and-patients
What are the risks/rate of re-occurrence and needing another round of treatment?
After the first treatment with intravenous immunoglobulin (IVIg), about one-third of children may need additional treatment in the following days to weeks to fully settle that episode of KD. This may include a second dose of IVIg or other medicines to help reduce inflammation and support recovery.
Once that episode of KD has completely resolved, the chance of a child developing KD again is very low. Studies show that only a small number of children (less than 2%) ever experience a second episode.
If a child has recovered from KD and their heart is normal, are there any other health problems they might face later in life, like autoimmune conditions?
If a child was appropriately treated with timely IVIg, had no coronary artery involvement, and inflammation fully resolved, most children will not experience ongoing problems related to KD.
KD does not appear to significantly increase the lifetime risk for other autoimmune conditions (such as lupus, rheumatoid arthritis, inflammatory bowel disease or multiple sclerosis). Large follow-up studies have not shown a consistent or strong association, and the immune system changes have not been shown to result in clinically meaningful disease if no recurrent or chronic inflammation occurs.
Children who fully recover typically have normal immune function after resolution and do not have higher rates of infections, allergies or chronic inflammatory conditions. If ongoing inflammation or recurrent KD episodes occur, re-evaluation with a specialist including counselling may help you understand these issues specifically for your child and family.
For all children whose echocardiograms (an ultrasound scan that shows how the heart muscle and heart vessels are working) are normal during and after KD, long-term cardiovascular outcomes are considered similar to the general population.
As clinicians, we would recommend that children and families take a proactive approach to long-term cardiovascular health and wellbeing to improve lifelong cardiometabolic risk. This includes heart-healthy habits including regular exercise, balanced diet, avoiding smoking and vaping, screening and management for diabetes and high blood pressure, manage cholesterol levels, avoid alcohol consumption and maintaining a healthy weight.
If, however, there was evidence of during or after KD of coronary artery dilatation (widening), aneurysms (see question 7) or heart dysfunction, children are considered to be at an increased lifetime risk of heart complications and the advice of your local cardiologist should be followed.