Methods for treating or preventing a Foxp3+ T regulatory cell (Treg) related disease in a subject in need thereof comprise administering to the subject an effective amount of a pharmaceutical composition comprising an inhibitor of a histone/protein acetyltransferase (HAT). Methods for identifying an agent useful for treating or preventing a Foxp3+ T regulatory cell (Treg) related disease comprise (a) contacting a candidate agent with a test sample comprising Foxp3+ T regulatory cells (Tregs), and (b) comparing a function of the Foxp3+ Tregs in the test sample with that in a control sample, wherein inhibition of the function of the Foxp3+ Tregs in the test sample when compared with the control sample indicates that the candidate agent is an agent useful for treating or preventing a Foxp3+ Treg related disease.
