The immune system is a network of cells, tissues, and organs that work together to protect the body from infection.
The human body provides an ideal environment for many microbes, such as viruses, bacteria, fungi, and parasites, and the immune system prevents and limits their entry and growth to maintain optimal health.
Some people think that many people on the autism spectrum have an impaired immune system which causes a range of immunological problems, such as oxidative stress.
Some people also think that this impaired immunity may cause or worsen some of the symptoms of autism, although this theory is disputed by many researchers.
Please see Impaired Immunity and Autism: Publications