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During challenge , rebiopsy was done when reticulin antibodies turned positive ( mean 0 . 6 years , range 0 . 2 - 2 . 0 ) or at the end of the two year study .
 reticulin antibodies
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 reticulin antibodies