Int Conf AIDS. 1996 Jul 7-12;11(2):9 (abstract no. We.A.264). Unique
Objective: Infection with the human immunodeficiency virus is
characterized by depletion of CD4+ T cells. In the past, it has been
difficult to determine the effects of HIV infection on the development
of the T-cell lineage. We have examined the ability of human peripheral
blood from HIV-infected patients to regenerate T-cells using a unique
chimeric organ culture system. Methods: Approximately 1 x 105 peripheral
blood mononuclear cells from 16 HIV-infected patients (CD4 count from 20
- 1072/microliter) and 8 control subjects were placed on
NOD/LtSz-scid/scid fetal thymus lobes in organ culture. Cells were
cultured for 12d and subsequently stained with antibody against
T-lymphocyte surface antigens and analyzed by flow cytometry. Culture
supernatants were analyzed for reverse transcriptase activity (RT) to
assess for viral replication in culture. Results: In all cases, the
total number of lymphocytes generated from the HIV-infected patients was
at least 3-fold fewer than in the controls. In addition, the number of
CD4+ and CD4/CD8 double-positive cells from patients was always below
those of control by at least 3-fold. The number of CD8 cells regenerated
in vitro from patients was variable. There was no relationship between
the number of regenerating CD4 or CD4/CD8-positive cells in vitro and
the patients' peripheral blood CD4 count, nor to RT activity in cultured
supernatants. Addition of zidovudine (1 and 10 micrograms/ml) to the
culture did not change the regenerative ability of cells from either the
patients or the controls. Moreover, regenerative ability of cells from
patients was not associated with whether the patient was taking
antiretroviral therapy or not. Conclusions: Regardless of peripheral
blood CD4 count or RT activity, regeneration of CD4 and CD4/CD8
lymphocytes in vitro by HIV-infected patients is diminished. Since
murine recipient tissue was used in this study, the effect of HIV on the
thymic microenvironment has been minimized, suggesting that this defect
resides in prethymocytes.
*CD4 Lymphocyte Count *CD4-Positive T-Lymphocytes/PHYSIOLOGY
*CD8-Positive T-Lymphocytes/PHYSIOLOGY *HIV Infections/PATHOLOGY