GSTM1 and systemic lupus erythematosus: 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.