Flow cytometry
Circulating Th2 cells were assessed as the proportion of peripheral blood CD4+ T cells expressing CRTh2 as we described previously [26, 34] (Fig. S1). CRTh2 levels on in vitro differentiated Th2 cells were determined as previously referenced [35] (Fig. S2). Briefly, cells were stained using antibodies against CD4, CRTh2 or isotype control and fixed with paraformaldehyde (2%). Flow cytometry analysis was performed using a BD LSR II Flow Cytometer, with gates set in accordance with the profiles of the isotype control and/or negative control beads. Results were analyzed using FlowJo® (TreeStar, Ashland OR, USA).