The Relationship between the Human Immunodeficiency Virus and the Acquired Immunodeficiency Syndrome (Draft)

DRAFT
300 cells per cubic millimeter (mm3) of blood in the absence of HIV antibodies or other
conditions or therapies associated with depressed levels of CD4+ T cells (reviewed in Fauci,
1993b; Laurence, 1993.)
In a CDC survey, only 47 individuals (.02 percent) among 230,179 individuals
diagnosed with AIDS fit these criteria (Smith et al., 1993). In the MACS, 22,643 CD4+ T cell
determinations in 2,713 HIV-seronegative homosexual men revealed only one individual with a
CD4+ T cell count persistently lower than 300 cells/mm3, and this individual was receiving
immunosuppressive therapy (Vermund et al., 1993a). A similar review of another cohort of
homosexual and bisexual men found no case of persistently lowered CD4+ T cell counts
among in 756 HIV-seronegative men who had no other cause of immunosuppression (Smith
et al., 1993).
Similar results were reported from the San Francisco Men's Health Study, a
population-based cohort recruited in 1984. Among 206 HIV-seronegative heterosexual and
526 HIV-seronegative homosexual or bisexual men, only one had consistently low CD4+ T cell
counts (Sheppard et al., 1993). This individual also had low CD8+ T cell counts, suggesting
that he had general lymphopenia rather than a selective loss of CD4+ T cells. No AIDSdefining clinical condition was observed among these HIV-seronegative men.
Studies of blood donors, transfusion recipients, and household contacts of transfusion
recipients also suggest that persistently lowered CD4+ T cell counts are extremely rare in the
absence of HIV infection (Aledort et al., 1993; Busch et al., 1994). Longitudinal studies of
injection-drug users also have demonstrated that unexplained CD4+ T-lymphocytopenia is
almost never seen among HIV-seronegative individuals in this population, despite a high risk
of exposure to hepatitis B, cytomegalovirus and other blood-bome pathogens (Des Jarlais et
al., 1993; Weiss et al., 1992).

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