Product selection of third-party ESTs. Recipient HLA is compared with 2 separate third-party products along with antiviral activity. Product 1 is a 5/8 HLA match with the patient, whereas product 2 is a 6/8 HLA match. On prior evaluation of products to determine through which alleles the product has antiviral activity, product 1 demonstrated antiviral activity in 3 of these shared alleles (HLA restriction), whereas product 2 had antiviral activity in only 1 shared allele. Because of this antiviral activity in more shared alleles, product 1 is chosen as the initial suitable product.