Progesterone favors the development of human T helper cells producing Th2-type cytokines and promotes both IL-4 production and membrane CD30 expression in established Th1 cell clones. - Piccinni,M.P.; Giudizi,M.G.; Giannarini,L.; Sampognaro,S.; Parronchi,P.; Manetti,R.; Annunziato,F.; Livi,C et al. (J Immunol 1995)