The causes of aplastic anemia are considered to be of three types: abnormalities in hematopoietic stem cells, abnormalities in the bone marrow microenvironment, and abnormalities in immune factors. Among these, abnormalities in immune factors play a dominant role. Therefore, most patients with aplastic anemia see some improvement after receiving immunosuppressive therapy clinically. However, there is a small subset of patients with aplastic anemia for whom immunosuppressive therapy is not effective, and the causes of the disease in these patients are not well understood and may be congenital, such as congenital dyskeratosis.