Dog Leukocyte Antigens (DLA) are the canine equivalent of major histocompatibility complexes (MHCs) in humans; these are cell surface proteins expressed by cells of the immune system (white blood cells, or leukocytes). DLA types have received considerable attention in recent years, as they are suspected to play a critical role in autoimmune diseases, and we are aware of this research. However, because DLA types reflect a functional portion of the canine immune system, and its ability to fight infectious disease and cancer, until DLAs are better understood, we do not feel it prudent to select for or against certain DLA types, as there may be benefits or reasons for the presence or commonness of certain DLA types that are not known, and unforeseen consequences could occur that would impact the health of those dogs. Optimal Selection contains markers in the DLA region and incorporates these data into the dog’s diversity analysis, but does not actively select for DLA types in isolation. By emphasizing overall diversity in breeding, we feel similar benefits in immune health can be obtained. More research is certainly needed on this subject.