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A 40-year - old man with relapsing - remitting multiple sclerosis ( MS ) developed primary central nervous system lymphoma ( PCNSL ) after having received 21 doses of natalizumab monotherapy .
 adverse effect: PCNSL, natalizumab; adverse effect: primary central nervous system lymphoma, natalizumab
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: adverse effect 
Text: {0} 
 Entity Pairs:  PCNSL, natalizumab; primary central nervous system lymphoma, natalizumab 
Answer:
 adverse effect: PCNSL, natalizumab; adverse effect: primary central nervous system lymphoma, natalizumab