You've gone through years of intense training and have access to all the coolest high-tech equipment. You know what immunodeficiency diseases are out there and how to treat them. You're just like Dr. House or Dr. Quinn, Medicine Woman—minus the cantankerous attitude or the way-outdated medical techniques.
Your knowledge as an immunologist makes you a highly valued member of society. The public is looking to you to keep them safe from allergies, infections, inflammations, and hives. You have the ability to improve and save lives.
So yeah, you have a lot of power...but only in certain circumstances. Your hospital or research lab will be your domain, which you'll be able to rule over with an iron fist.
You'll be able to say, "Yes, Stan, I needed those samples returned to me five minutes ago," or "Ugh, Marie, put another scoop of sugar in this coffee." But you won't have, like, President of the United States power, where you can walk into pretty much any room anywhere, point at someone, and say, "Get him out of my sight."
Just stick to your stomping grounds at the hospital or lab, and you'll wield all the power you could hope for. Except over the diseases themselves, which might still take some wrestling to get under control.