Angiokines, angiogenesis and angiolymphoproliferative syndromes (ALPS).

In earlier experiments we had noted that transformed and leukemic leukocytes produced an RNA-rich angiogenic lymphokine. The formation of capillaries is a stepwise process in which reticulum cells first become detached and attracted to a site (mobilization and migration along a reticulin network). This is followed by local proliferation and finally by elongation and alignment against a basal membrane in tubular geometry. Coincidental with the last step is a biochemical and immunochemical differentiation of the endothelial cells manifested by the appearance of alkaline phosphatase, angiotensin-converting enzyme, factor VIII and the generation of receptors for thrombin as well as the capacities to produce prostacyclin and fibronectin on demand. It is postulated that there may be not one but several angiogenic lymphokines (angiokines) for each step of capillary development. Angiokine 1 (AK1) for the mobilization-chemotactic-migration, AK2 for the local proliferative, and AK3 for differentiating-morphogenic events. The above postulate aids in the classification and understanding of a number of angiolymphoproliferative syndromes since these reflect different disorders of the stepwise vessel formation. The association and the simultaneous proliferation of vascular and lymphoid elements is a feature that a number of lymphoproliferative disorders, of otherwise differing nature, have in common. To this effect they have been grouped in this study as angiolymphoproliferative syndromes (ALPS). These are a group of prelymphomatous or prelymphomogenic clinicopathologic entities in which proliferation of a lymphoid element (cell) is coupled with the accelerated development of blood capillaries and postcapillary venules.