We have examined the capacity of peripheral blood T cells from RA patients to be polarized in vitro towards a type 1 (T1) or a type 2 (T2) phenotype. Peripheral blood T cells from RA patients and from healthy donors were primed by 1 week of culture with soluble OKT3 in the presence of polarizing cytokines. The recovered T cells were restimulated and their cytokine secretion profile determined. Priming of T cells from RA patients in the presence of recombinant (r)IL-2 plus rIL-12 induced a shift towards a T1 pattern, characterized by increased production of interferon-gamma, that was more pronounced than in the case of healthy donors. Conversely, priming of T cells from RA patients in the presence of IL-4 failed to induce a shift towards a T2 profile after 1 week, whereas it induced T cells from healthy donors to acquire such a profile characterized by heightened production of IL-4, IL-5 and IL-13. However, a T2 polarization profile emerged in T cells from RA patients that were primed in the presence of rIL-4 and subsequently maintained in culture in rIL-2 alone for 1 or 2 additional weeks. We conclude that in vitro differentiation of peripheral T cells towards a type 2 phenotype is impaired in RA. Nevertheless, conditions required to drive peripheral T cells towards a type 2 phenotype were established. Administration of autologous polyclonal T cells expressing a type 2 cytokine secretion profile is proposed as a therapeutic strategy in RA.