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| Workshop I Lymphocyte Subsets and Immune Regulation | ||
Abstract I.8   | ||
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| 1Department of Theoretical Biology, Utrecht University, Utrecht and 2Department of Clinical Viro-Immunology, CLB, Amsterdam, The Netherlands | ||
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| Mathematical models are required for the interpretation of T cell receptor excision circle data | ||
| R.J. de Boer1, B.E. Dutilh1, M.D. Hazenberg2, and F.M. Miedema2 | ||
 ecent thymic emigrants (RTE) have been identified by T cell receptor excision circles (TRECs) that are formed during T cell receptor rearrangement. The average number of TRECs per naive T cell decrease with age, after thymectomy, and in diseases perturbing T cell homeostasis (like HIV-1 infection and rheumatoid arthritis). These observed decreases in the TRECs per naive T cell are typically taken as evidence for a declining thymic output. This remains ambiguous however because TRECs are diluted when naive T cells divide. We recently developed a mathematical model to dissect the effects of thymic production and peripheral T cell division on the TRECs (Hazenberg et al., 2000). Our analysis indicates (i) that TRECs can only decrease with age if there is naive T cell homeostasis, (ii) that the rapid loss of TRECs observed during disease is an indicator of increased division rates rather than decreased thymic output, and (iii) that during disease the TRECs will approach a new steady state and will hence become independent of the duration of the disease. | ||
| Hazenberg M.D., et al. (2000) Nat. Med., 6: 1036–1042. | ||
