Thymic size and CD4+ cell recovery in HIV-infected patients during long-term highly active antiretroviral therapy

Abstract number: 1134_01_261

Kolte L., Lerbæk A., Ersbøll A.K., Strandberg C., Nielsen J.O., Nielsen S.D.


The human thymus is suggested to be contributing to de novo T cell synthesis even late in life. Such synthesis can be assessed by analyzing thymic output markers such as thymic size. In HIV-infected patients reconstitution in the peripheral CD4+ cell pool during the first phase of highly active antiretroviral therapy (HAART) seems to be thymic-associated. To investigate whether this is a prolonged effect 25 HIV-infected patients in steady state HAART and with known thymic size were followed prospectively with CD4 counts and HIV-RNA measurements every third month in a follow-up period of 12 months.


Thymic size was determined by computer tomography (CT) at inclusion in the study and T-cell subpopulations were determined at follow-up by flow cytometry.


The correlation between thymic size and CD4 counts was significant at inclusion in the study (r = 0.498; P = 0.011) and remained almost unaltered at 3, 6 and 9 months of follow-up (r = 0.449, P = 0.036 after 3 months, r = 0.517, P = 0.012 after 6 months, r = 0.478, P = 0.021 after 9 months). However, with regard to CD4 increase no difference was found between patients with minimal and abundant thymic tissue, respectively, at any time of follow-up.


The measurement of thymic size at baseline may be of importance regarding the initial increase in CD4+ cells in HIV-infected patients receiving HAART, but does not seem important to a continued increase in CD4+ cells during long-term HAART in a follow-up period of 12 months. Whether thymic size is important to a continued increase in CD4+ recent thymic emigrants estimated by measuring other thymic output markers such as naïve CD4+ cells and TREC-containing CD4+ cells is still not known. The included patients in this study are still followed and the abovementioned measurements at follow-up will be performed.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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