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The mRNA for the Duffy blood group antigen , the erythrocyte receptor for the Plasmodium vivax malaria parasite , has recently been cloned and shown to encode a widely expressed chemokine receptor .
 chemokine receptor, Duffy blood group antigen, mRNA, erythrocyte receptor
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:
 chemokine receptor, Duffy blood group antigen, mRNA, erythrocyte receptor