CD4 and T-cell non-Hodgkin lymphoma: Because CD4 antigen is present in the most of T cell lymphoma and some T lymphocytic leukemia cells [19], but it is not highly expressed in hematopoietic stem cells and non-hematopoietic cells, the property makes CD4 antigen as an ideal target in CAR-T cell therapy against T cell lymphoma and some T lymphocytic leukemia [20].