FOXP3 and viral infectious disease: The impact of FOXP3+ cells in host defence appears to vary with the pathogen as well as the cell manipulations used in in vivo and in vitro experimental systems [23] Thus, in some viral infections they provided protection [24] in some bacterial infections they are detrimental [25] and in some parasitic infections including malaria, they had no effect [26] Therefore, we investigated the role of CD25+FOXP3+ Treg cells in the anergic form of lepromatous leprosy.