PTPA and asthma: While our in vitro systems were unable to recapitulate the recent in vivo observations regarding the importance of PP2A in Treg cell function [32], it is an intriguing possibility that the decrease in PP2A expression observed in the mediatstinal lymph nodes of mice with allergic airway inflammation, and in the peripheral blood monocytes of patients with glucocorticoid resistant asthma, might be associated with Treg cell dysfunction.