CD4 and HIV infectious disease: There were significant differences in the distributions of CD4 cell counts by the routes of HIV infection and by the year of HIV diagnosis (heterosexual contact: χ2 = 119.63, p<0.01; male-to-male sexual contact: χ2 = 21.07, p<0.01; IDUs: χ2 = 191.85, p<0.01; and commercial blood plasma donation: χ2 = 66.95, p<0.01).