PTX3 and systemic lupus erythematosus: PTX3 levels of patients with SLE correlated with disease activity as assessed by SLEDAI-2K in the whole group of patients (rho = 0.361; p = 0.007, n = 55) and in those who were off corticosteroids (p < 0.001, n = 19; Table 3), but not in patients receiving prednisone.