6425
Numerous cellular and biochemical abnormalities in immune regulation have been described in patients with systemic lupus erythematosus ( SLE ), including surface Ag receptor -initiated signaling events and lymphokine production .
 Ag receptor, lymphokine
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:
 Ag receptor, lymphokine