The density of infiltrated CD68+ macrophages in glomeruli correlated with age, SLEDAI, SLE duration, LN duration, PLT, Hb, blood urea nitrogen (BUN), UA, C3, C4, CD3, CD8, AIs, and CIs, with the highest Spearman correlation coefficients (r) being 0.41. This evidence concerns the gene C4A and systemic lupus erythematosus.