In accordance to study by Chowdhury and colleagues [38], the existence of EC groups 2–5 cannot be explained by differences in age, gender, race, and ethnicity of individuals, as well as the presence of protective alleles HLA-B*57/B*27/B*5801, the duration of HIV infection, viral load, the ratio of CD4+ / CD8+ cells, total CD4+ counts, the neutralizing breadth of HIV-specific antibodies, and the breadth and magnitude of HIV-specific cytotoxic response. The gene discussed is CD4; the disease is HIV infectious disease.