PTX3 and lupus nephritis: The average level of serum PTX3 in the discovery cohort of lupus nephritis was significantly higher than that in SLE without renal involvement group (3.270 (0.349–56.376) vs. 1.065 (0.040–9.098) ng/ml, P < 0.001), minimal change disease group (3.270 (0.349–56.376) vs. 1.021 (0.105–2.940) ng/ml, P < 0.001), and normal controls (3.270 (0.349–56.376) vs. 0.993 (0.007–2.655) ng/ml, P < 0.001) (Figure 1A).