CD4 and AIDS: The papers with the highest indegree in sub-modules 1A, 1D and 1E are, respectively, “Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment,”[42] “Rapid turnover of plasma virions and CD4 lymphocytes in HIV-1 infection”[43] and “Identification of a reservoir for HIV-1 in patients on highly active antiretroviral therapy”.[44] These papers report and explain fundamental changes in the clinical reality of HIV/AIDS produced by the implementation of anti-retroviral therapies.