H270 is a designation for a specific type of human leukocyte antigen (HLA) that plays a crucial role in the immune system. It helps the body recognize which cells are its own and which are foreign, thus aiding in the immune response against infections and diseases. This antigen is part of the HLA system, which is essential for tissue compatibility in organ transplants. Variations in H270 can influence susceptibility to certain autoimmune diseases and affect how individuals respond to various treatments, making it an important area of study in immunology and transplant medicine.