What it is
A rare and deadly mutation of the immune system, making the patient vulnerable to sickness.
Science behind it
There are two cells, T-cells and B-cells, that warn the immune system when a virus is invading. This way, the system can prepare and gather its strength for fighting off the intruder.
Living with it
This is a hereditary disease that will reveal itself during the first months of one's life. There are no cures that have been discovered, so putting up with the chronic cough, ear and sinus infections, and rashes that come with it isn't an option.