As expected from the higher proportion of recent infections, MSM had a higher median CD4 cell count (435, interquartile range (IQR) 259–585 cells/mm3) than the corresponding CD4 values found in heterosexuals (median 280, IQR 110–458 cells/mm3) and in IDU (median 392, IQR 197–521 cells/mm3) (p<0.0001). The gene discussed is CD4; the disease is infection.