Immune system build up after discontinuing Humira?

I was prescribed Humira for my ulcerative colitis. I was on this tnf blocker from April 2009-March 14, 2011. Due to the detection of latent TB in March, I had to discontinue the use of Humira. What I want to know is how long it takes for the immune system to build up back to the way it's supposed to be?