T regulatory cells: aid or hindrance in the clearance of disease?

CD4(+) CD25(+) T regulatory cells (Tregs) are classified as a subset of T cells whose role is the suppression and regulation of immune responses to self and non-self. Since their discovery in the early 1970s, the role of CD4(+) CD25(+) Tregs in both autoimmune and infectious disease has continued to expand. This review exam-ines the recent advances on the role CD4(+) CD25(+) Tregs may be playing in various diseases regarding pro-gression or protection. In addition, advances made in the purification and manipulation of CD4(+) CD25(+) Tregs using new cell markers, techniques and antibodies are discussed. Ultimately, an overall understanding of the exact mechanism which CD4(+) CD25(+) Tregs implement during disease progression will enhance our ability to manipulate CD4(+) CD25(+) Tregs in a clinically beneficial manner.