PTX3 and lupus nephritis: Thus, the lupus nephritis patients in our study were further divided into two groups according to their serum anti-PTX3 auto-antibodies and PTX3 levels: patients in group 1 were anti-PTX3 auto-antibodies negative and with higher serum PTX3 levels (≥3.207 ng/ml), while patients in group 2 were anti-PTX3 auto-antibodies positive and with lower PTX3 levels (<3.207 ng/ml).