Compared to unilateral varicocele patients, inflammatory response pathways were dysregulated in bilateral varicocele, with an underexpression of alpha-1-acid glycoprotein 1 (ORM1), alpha-1-acid glycoprotein 2 (ORM2), SERPINA1, GGT1, apolipoprotein D (APOD) and FN1, and an overexpression of ECM1, polymeric immunoglobulin receptor (PIGR) and ALDR. Here, APOD is linked to varicocele.