My major research line encompasses the quantification of leukocyte dynamics.

Despite enormous advances in the field of immunology, many quantitative insights

in immunology are still badly lacking, including the expected lifespan of different

types of leukocytes, the contribution of thymus and bone marrow output to leukocyte

homeostasis, and changes in lymphocyte diversity during ageing.

This lack of information hampers our understanding of the immunological changes

that occur during healthy ageing, and in different diseases. Our research aims to

reveal such quantitative insights by taking an interdisciplinary approach in which

experimental immunologists and mathematicians work together on a daily basis.

Using in vivo stable isotope labelling we study the daily production rates of different

types of leukocytes, how they are maintained during healthy ageing, and how these

processes are disturbed in diseases such as leukemia, HIV infection, and after

haematopoietic stem-cell transplantation. Our quantitative approach has also pointed

out that T-cell maintenance occurs fundamentally differently in mice and men,

underlining the need for more in vivo studies in humans.