Polymorphonuclear leukocytes and monocytes/macrophages in the pathogenesis of cerebral ischemia and stroke.

BACKGROUND: The extent to which polymorphonuclear leukocytes and monocytes/macrophages contribute to the pathobiology of cerebral ischemia and stroke is an issue of long-standing contradiction and controversy. Recent developments in the ability to selectively modify leukocyte adhesion with antiadhesion antibodies and the potential clinical application of this therapeutic approach have spurred a resurgence of experimental studies examining the role of leukocytes in cerebral ischemia and stroke. SUMMARY OF REVIEW: We review studies examining leukocyte accumulation, initiation of thrombosis, and exacerbation of ischemic brain injury in stroke, and we examine other proposed contributions of leukocytes to cerebrovascular pathophysiology. CONCLUSIONS: The importance of specific characteristics of a given ischemia model and of underlying stroke risk factors in determining the degree of leukocyte involvement and effectiveness of therapies directed against these cells is discussed.