With respect to the route of HIV-1 transmission, however, a significantly higher mean (± SD) increase from baseline in CD4+ T cells was observed among MSM/bisexual men compared to heterosexual men and women (231 ± 136 vs. 163 ± 100 cells/μL, p = 0.01) after 12 months, despite no significant baseline differences between the two groups in clinical stage (44% of AIDS-presenters in heterosexuals vs. 29% among MSM, p = 0.1) and age (44.1 years in heterosexuals vs. 43.2 in MSM, p = 0.73). The gene discussed is CD4; the disease is AIDS.