It’s not a normal (or common) consequence of J-pouch surgery. Do you know if they were high before your surgery? Does your doctor have an opinion about what’s going on?
You don’t say how high they are, and that can make a difference. Normal ranges of labs tests provide useful guidance, but they aren’t god-given. My WBC and eosinophils always run high, perhaps related to autoimmunity, though I wouldn’t describe the values as very high.