Differences in CD4 Cell Counts at Seroconversion and Decline Among 5739 HIV-1–Infected Individuals with Well-Estimated Dates of Seroconversion - Giota Touloumi, Nikos Pantazis, Abdel Babiker, A. Sarah Walker, Olga Katsarou, Angelos Hatzakis, Anastasia Karafoulidou, Kholoud Porter; Janet Darbyshire, CASCADE Collaboration (JAIDS Journal of Acquired Immune Deficiency Syndromes, 2003)