However, the CD4+ as well as the CD4- NKT cell fractions in RA patients contained significantly fewer IL-4 producing cells as compared with their counterparts in healthy control individuals (for CD4+ NKT cells: IFN-γ+ 57.2 ± 12.9%; IL-4+ 5.8 ± 1.5%; IFN-γ+IL-4+ 37.0 ± 13.2%; and for CD4- NKT cells: IFN-γ+ 72.1 ± 12.4%; IL-4+ 3.3 ± 1.9%; IFN-γ+IL-4+ 24.6 ± 11.9%), indicating that both CD4+ and CD4- NKT cells in the peripheral blood of RA patients are biased toward a Th1-like cytokine profile. This evidence concerns the gene IL4 and rheumatoid arthritis.