Expression of costimulatory markers CD80 and CD134 on IL-17+ CD3+ cells in SLE. (a) Percentages of CD80+ IL-17 producing CD3+ cells in patients with SLE (n = 30) and healthy controls (HC) (n = 13). (b) The expression of CD134+ on IL-17 producing CD3+ cells from patients with SLE (n = 30) and healthy controls (HC) (n = 13). (c) Percentages of CD80+ and CD 134+ IL-17 producing T cells form active (n = 15) and inactive (n = 15) patients with SLE and healthy controls (n = 13). (d) Expression of CD80+ and CD 134+ on IL-17 producing T cells from patients with lupus nephritis (with LN) (n = 13), patients without lupus nephritis (without LN) (n = 14) and healthy controls (n = 13). Data are shown as mean value. Significance was tested by the Mann-Whitney U-test. A P-value less than 0.05 was considered significant.