The number of total CD68+ macrophages per glomerular area was greatest in class IV renal biopsies, with mean macrophage numbers about 2.5 times higher compared to SLE ISN/RPS class V (Fig. 1a; p < 0.001) and about 2.4 times higher compared to SLE ISN/RPS class II (Fig. 1a; p < 0.05). The gene discussed is CD68; the disease is systemic lupus erythematosus.