Introduction

Ageing is associated with changes in the peripheral T-cell immune system, which can be significantly influenced by latent cytomegalovirus (CMV)-infection. Therefore, we wanted to investigate how changes in circulating T-cell populations correlate with T-cell composition of the lymph node (LN), which is crucial for a comprehensive understanding of the T-cell system.

Materials and methods

T cells from peripheral blood (PB) and LN of 38 end-stage renal disease patients were analyzed for frequency of recent thymic emigrants (using CD31 expression within naive cells and T-cell receptor excision circle (TREC) content), relative telomere length and expression of differentiation markers.

Results

Compared with PB, LN contained relatively more CD4⁺ than CD8⁺ T cells (p<0.001). The TREC-content in T cells was significantly higher in the LN (p=0.002). The percentage of naive and central memory (CM) CD4⁺ and CD8⁺ T cells and thymic output parameters, showed a strong linear correlation between PB and LN (p=0.026 for CM CD4⁺ T cells and p<0.001 for the other parameters). Highly differentiated CD28^null T cells, being CD27^–, CD57⁺ or PD-1⁺ were almost exclusively found in the circulation but not in LN. An age-related decline in naive CD4⁺ and CD8⁺ T-cell frequency was observed (p=0.035 and p=0.002, respectively) within LN, concomitant with an increase in central memory CD8⁺ T cells (p=0.033). Latent CMV-infection dramatically increased the frequency of circulating terminally differentiated T cells, leading to increased frequencies of CD4⁺CD28^null and CD8⁺CD28^null T cells showing decreased expression of CD27 and increased expression of PD-1 and CD57. However, this effect of CMV was not observed in the LN-derived T-cell population.

Conclusions

Overall T-cell composition and measures of thymic function in PB and LN are strongly correlated. However, highly differentiated CD28^null T cells, which may comprise a large part of circulating T cells in CMV-seropositive individuals, are almost exclusively found within the circulation.

CITATION INFORMATION: Dedeoglu B, de Weerd A, Huang L, Langerak A, Klepper M, Verschoor W, Reijerkerk D, Baan C, Litjens N, Betjes M. T-Cell Aging Parameters in the Lymph Node and Peripheral Blood Are Strongly Associated but Terminally Differentiated T Cells Are Mainly Located within the Circulation. Am J Transplant. 2017;17 (suppl 3).

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