HLA-DRA and nasal cavity polyp: HLA-DRA has not been linked to AERD but other HLA class II genes have [54], however, the same study that linked HLA-DRA to the presence of nasal polyps among asthmatic patients found two HLA-DRA polymorphisms to be potential markers for nasal polyp development in aspirin-tolerant asthma compared to the AERD subgroup [36].