13335
The two Duffy polymorphic antigens , Fya and Fyb (coded by the FY*A and FY*B alleles ), are present on erythrocyte membranes .
 erythrocyte membranes, Duffy polymorphic antigens, Fya, Fyb
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:
 erythrocyte membranes, Duffy polymorphic antigens, Fya, Fyb