Entrapment of recent thymic emigrants in lymphoid tissues from HIV-infected patients: association with HIV cellular viral load.
OBJECTIVE
Depletion of thymus derived naive T-cells is a feature of HIV infection. Here the impact of HIV infection on the compartmentalization of recent thymic emigrants of (RTE) and naive T-cells was examined.


METHODS
Peripheral blood mononuclear cells (PBMC) and lymphoid tissue (LT) from 43 HIV-infected patients and 12 controls were examined for RTE distribution by measuring coding joint T-cell receptor excisional circles (cjTREC) by PCR and naive and memory T-cell subsets and adhesion molecules (L-selection, LFA-1) by flow cytometry.


RESULTS
In HIV-infected patients, the RTE as quantified by cjTRECs in CD4 LT cells were significantly higher than in PBMC. Their values, however, were less than in control subjects, in both the LT and PBMC compartments. This was associated with an increase in L-selectin and LFA-1 expression on LT derived T cells. In PBMC, a significant positive relationship between TREC and naive CD4 cells and an inverse relationship between TREC and cellular viral load (CVL) was observed. Whereas in LT, there was a positive relationship between cjTREC and both naive CD4 cell percentage and CVL.


CONCLUSIONS
Collectively, the data suggests that LT is a significant reservoir for RTE. The RTE appeared to be entrapped in LT from HIV-infected subjects. Such entrapment is probably a response to the high viral load in these tissues. These observations may partially explain the decline in RTE observed in the peripheral blood of HIV-infected patients, and the delay in recovery of naive cells in blood after initiation of HAART.
Nokta
Mostafa A
MA
University of Texas Medical Branch, Galveston 77555, USA.
Li
Xiao-Dong
XD
Al-Harthi
Lena
L
Nichols
Joan
J
Pou
Anna
A
Asmuth
David
D
Landay
Alan
A
Pollard
Richard B
RB
D000328:Adult; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D019041:L-Selectin / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D008221:Lymphoid Tissue / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology*; D019562:Viral Load
D016169:Lymphocyte Function-Associated Antigen-1; D012367:RNA, Viral; D011948:Receptors, Antigen, T-Cell; D019041:L-Selectin