In healthy human brain/spinal cord, blood capillaries and venules are locked differently with junctions and basement membrane (blood-brain barrier, blood-venule barrier). In choroid plexus, epithelial tight junctions and basement membrane lock bloodcerebrospinal-fluid (CSF) barrier. Lymphocytic cell data, quantified with multicolour flow-cytometry or immuno-cytochemical methods in sample pairs of lumbar CSF, ventricular CSF and peripheral venous blood, are taken from references; similarly, data of thoracic duct chyle and blood sample pairs. Through three circumventricular organs (median eminence, organum vasculosum lamina terminalis, area postrema), 15-30 ll blood are pressed by blood pressure through fenestrated capillaries, matrix/basement membrane spaces and ependyma cell lacks into ventricular/suboccipital CSF to generate CD31 , CD4
CD31 cell counts in ventricular and lumbar CSF, higher CD31 subsets in lumbar CSF, and few NK and B cells due to absorption in circumventricular organs. The Marburg CSF Model reflects origin and turnover of lymphatic cells in CSF realistically; the model differs from ligand-multistep processes of activated lymphocytes through blood-brain-, blood-venule-, and blood-CSF-barriers; because transfer of inactivated native lymphocytes through the barriers is not found with healthy humans, although described so in literature. V C 2015 International Society for Advancement of Cytometry