title: CD4 counts as surrogate markers for progression to AIDS.
authors.forename: S D
authors.initials: SD
authors.lastname: Nightingale
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes; D006801:Humans; D007958:Leukocyte Count; D016016:Proportional Hazards Models