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In previous studies, it was shown that the fusion region of the pml/RAR-alpha protein , expressed by acute promyelocytic leukemia (APL) cells , can be specifically recognized in vitro by donor (D. E.) CD4 T cells in a HLA class II DR11-restricted fashion .
 CD4 T cells, HLA class II, pml/RAR-alpha protein, acute promyelocytic leukemia (APL) cells
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 CD4 T cells, HLA class II, pml/RAR-alpha protein, acute promyelocytic leukemia (APL) cells