CD4 lymphocyte counts within 24 months of human immunodeficiency virus seroconversion. Findings in the US Navy and Marine Corps. The Navy Retroviral Working Group.

BACKGROUND: Although CD4 lymphocytes are the primary target of the human immunodeficiency virus (HIV), few studies have evaluated CD4 cell counts in a large population of seroconverters with known dates of seroconversion. This study reports an analysis of CD4 lymphocyte counts and CD4 cells as a percentage of all lymphocytes within 24 months of estimated date of HIV seroconversion in 1046 HIV seroconverters.
METHODS: Study participants included all Navy and Marine Corps seroconverters (1023 men, 23 women) from 1987 through 1991 with a previous negative HIV test. CD4 lymphocyte counts and percentages were obtained for blood drawn from HIV seroconverters during initial clinical evaluations carried out at Naval Medical Centers in Bethesda, Md; Oakland, Calif; Portsmouth, Va; and San Diego, Calif. The seroconversion date was estimated as the midpoint between the last negative test date and the first positive test date.
RESULTS: Nearly 40% of seroconverters presented with initial CD4 lymphocyte counts lower than 0.50 x 10(9)/L (500/microL) and 3% with counts lower than 0.20 x 10(9)/L (200/microL). Approximately half the seroconverters presented with fewer than 29% CD4 cells, and 5% presented with fewer than 14% CD4 cells. There were no significant differences in CD4 counts according to sex, race, or estimated duration of HIV infection.
CONCLUSIONS: Little difference in CD4 lymphocyte counts or percentages by duration of infection within 24 months was evident on initial clinical evaluation of HIV seroconverters. The high percentage of seroconverters presenting with low CD4 counts or percentages suggests a population of seroconverters with rapid depletion of CD4 lymphocytes following seroconversion.