DONOR AND RECIPIENT MATCHING
Tissue type matching
Your immune system is designed to keep you safe from foreign invaders such as viruses and bacteria. Everyone has special proteins on their cells called HLA proteins. Your combination is unique to you and is recognised by your immune system so it will not attack your own cells.
Your immune system will recognise a combination of foreign proteins not belonging to you and will attack them. It will then develop cytotoxic antibodies against these HLA proteins. This is how your immune system defends your body against infections. This is also the underlying cause of your body rejecting a transplant and the reason you need to take anti-rejection medications.
Cytotoxic antibodies are called donor specific antibodies if they are shown to be against your potential donor’s HLA proteins. These can make it hard for you to be compatible with other donors. These antibodies may have developed because you have previously been exposed to other people’s HLA proteins through a blood transfusion, through pregnancy, or from a previous transplant. Sometimes there is no clear reason found for the presence of these HLA-antibodies.
Your immune system remembers this exposure and is ready to attack cells with similar HLA-proteins on them. The cross match test also checks for this.