Now, tissue typing is actually a pretty complicated process so we're not going to go into too much details. But what tissue typing basically is it's a process of determining the type of major histocompatibility complexes and a type of self antigens that are found within that host individual. And then finding the exact match or a very similar match, a compatible match from another individual that contains very similar MHC antigen complexes. So tissue typing is the process that involves determining the major histocompatibility complex antigens of the host individual and finding a donor that is most compatible that contains the least mismatches. Another important type of method that is used to basically solve these complications and is probably used virtually on all cases of grafting an organ transplant is immunosuppression. Now, immunosuppression deals with using different types of chemical agents that are extracted from other organisms or synthesized in a lab.