High prevalence of thymic tissue in adults with human immunodeficiency virus-1 infection.
The thymus in adults infected with the HIV-1 is generally thought to be inactive, both because of age-related involution and viral destruction. We have revisited the question of thymic function in adults, using chest-computed tomography (CT) to measure thymic tissue in HIV-1-seropositive (n = 99) or HIV-1-seronegative (n = 32) subjects, and correlating these results with the level of circulating CD4(+) and CD8(+) T cells that are phenotypically described as naive thymic emigrants. Abundant thymic tissue was detectable in many (47/99) HIV-1-seropositive adults, aged 20-59. Independent of age, radiographic demonstration of thymic tissue was significantly associated with both a higher CD4(+) T cell count (P = 0.02) and a higher percentage and absolute number of circulating naive (CD45RA+CD62L+) CD4(+) T cells (P < 0.04). The prevalence of an abundant thymus was especially high in younger HIV-1-seropositive adults (</= 39 yr) with CD4 counts in the range 300-500 cells/microl and in older subjects (> 40 yr) regardless of CD4 count (P = 0.03). These studies suggest that the thymus is functional in some but not all adults with HIV-1 disease.
McCune
J M
JM
The Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, California 94141-9100, USA. Mike_McCune.givi@quickmail.ucsf.edu
Loftus
R
R
Schmidt
D K
DK
Carroll
P
P
Webster
D
D
Swor-Yim
L B
LB
Francis
I R
IR
Gross
B H
BH
Grant
R M
RM
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003430:Cross-Sectional Studies; D015497:HIV-1; D006801:Humans; D008875:Middle Aged; D013950:Thymus Gland / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed