Hla

This review offers an elementary introduction to the HLA system. The assays for each locus are presented to describe how HLA phenotypes are derived. Then the genetics of the codominant alleles at each locus are discussed with special attention to their linkage in haplotypes. A brief description of the molecular structure of HLA antigens and a detailed look at the most commonly used formulas in HLA population genetics follow. The major applications of the HLA system, allograft transplantation and HLA-disease associations, are indicated. Variation in the HLA polymorphism and its potential for population studies are also discussed.