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Katrin S Blum

Publications and source records attributed to Katrin S Blum.

2 recordsLinked to original sources

Lymphocyte numbers and subsets in the human blood. Do they mirror the situation in all organs?

Lymphocyte numbers in the blood are used to evaluate the immune status on a daily basis in medicine. Several studies have documented the normal ranges of lymphocytes and lymphocyte subsets in the peripheral blood. A variety of techniques and criteria have revealed clear differences between the lymphocyte subsets in childhood and adolescence. Race and gender are also variables for blood lymphocytes, and even environmental factors seem to influence the numbers of some lymphocyte populations. However, do all these variations in lymphocyte subsets in the peripheral blood mirror changes in the lymphocyte populations of the whole body, or is it just a result of different migratory habits of cells? The factors influencing the distribution of lymphocytes in the peripheral blood with regard to the different abilities of T and B cells to migrate to distinct lymphoid or non-lymphoid tissue are summarized. In addition it will be described how the removal of organs (e.g. thymus, spleen, liver) influences the distribution of lymphocytes in the blood. All these parameters should be considered not only in the clinical situation when the immune status of a patient is extrapolated from the lymphocyte numbers in the blood, but also when interpreting treatment effects in patients.

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Keystones in lymph node development.

New molecular markers are constantly increasing our knowledge of developmental processes. In this review article we have attempted to summarize the keystones of lymphoid tissue development in embryonic and pathological conditions. During embryonic lymph node development in the mouse, cells from the anterior cardinal vein start to bud and sprout, forming a lymph sac at defined sites. The protrusion of mesenchymal tissue into the lymph sacs forms the environment, where so-called 'lymphoid tissue inducer cells' and 'mesenchymal organizer cells' meet and interact. Defects of molecules involved in the recruitment and signalling cascades of these cells lead to primary immunodeficiency diseases. A comparison of molecules involved in the development of secondary lymphoid organs and tertiary lymphoid organs, e.g. in autoimmune diseases, shows that the same molecules are involved in both processes. This has led to the hypothesis that the development of tertiary lymphoid organs is a recapitulation of embryonic lymphoid tissue development at ectopic sites.

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