LN patients showed the lowest absolute numbers of PTX3+ B cells among total peripheral B cells, which were also significantly decreased in comparison with HD and non-renal SLE [mean ± standard deviation (SD) cells/ml: LN 0.023 ± 0.027 vs. HD 33.09 ± 48.15, p = 0.008; LN 0.023 ± 0.027 vs. non-renal SLE 12.53 ± 20.24, p = 0.033] (Figure 2A, left). This evidence concerns the gene PTX3 and systemic lupus erythematosus.