Leukocyte recruitment

Frequently, the EAR is followed by a late phase response 4-6 h later and it is caused by the pulmonary sequestration of eosinophils, neutrophils, mast cells, and T-lymphocytes. This leukocyte recruitment depends on mast cell-derived mediators such as TNFa and various chemokines, as well as on the expression of adhesion molecules on leukocytes (e.g. VLA-4, CD11/18) and vascular endothelial cells (e.g. VCAM-1, ICAM-1, E-selectin). Products of these leukocytes have several functions First, they cause the second phase of bron-choconstriction, mucus secretion, and airway swelling second, they cause tissue destruction third, they launch and entertain the chronic inflammation. 

It seems obvious to assume that by virtue of their powerful regulatory effects of leukocyte recruitment, many chemokine/chemokine receptors may play an important role in an inflammatory disease of the joints such as RA. However, chemokines may have other effects in disease pathogenesis that may not be related to leukocyte chemotaxis. 

Eriksson EE. Mechanisms of leukocyte recruitment to atherosclerotic lesions future prospects. Curr Opin Lipidol 2004 15(5) 553—558. 

Welt E, Tso C, Edelman E, et al. Leukocyte recruitment and expression of chemokines following different forms of vascular injury. Vase Med 2003 8 1-7. 

McEver RP, Cummings RD. Role of PSGL-1 binding to selectins in leukocyte recruitment. J Clin Invest 1997 100 S97-S103. 

Potential etiologic agents in cotton dust that release histamine are shown in Table VII. Some of these are effector molecules having potent biological effects in minute concentrations, i.e. peptides, which may act directly to affect chemotaxis and leukocyte recruitment, and also to release histamine and stimulate respiratory smooth muscle contraction. These bifunctional effector molecules are of major importance in considering pathogenic mechanisms in byssinosis. 

Clinical studies of cotton mill workers who had previously demonstrated a decreased expiratory flow measured by flow volume curves and FEV during cotton dust exposure showed an increase in WBC to 25.5% after 4 hours of exposure. Segmented neutrophils increased most (33%), while eosinophil mean counts did not change. The ratio of segmented neutrophils to epithelial cells from nasal mucosal swabs increased from 0.56 before to 1.84 after 4 hours of exposure. Peripheral blood and PMN counts increased upon exposure to cotton dust, and PMN were recruited to the nasal mucosa. Chest tightness and decreased flow were temporarily correlated with leukocyte recruitment following cotton dust exposure (2). 

Various adhesion molecules are reported to be expressed on vascular endothelial cells at sites of inflammation (Libby, 2002). In fact, VCAM-1, expressed on the surface of vascular endothelial cells in response to inflammatory stimuli, is suggested to play an important role in leukocyte recruitment (Gerrity et al, 1979). The adhesion of monocytes to vascular endothelial cells is the first critical step in the induction of atherosclerosis (Glass and Witztum, 2001). Supportively, the expression of VCAM-1 is reported to increase in atherosclerosis lesions (Cybulsky and Gimbrone,... 

Extracellular S100A8/A9 heterodimer exhibits cytokine-like functions, e.g. enhancing leukocyte recruitment to inflammatory sites and AA transportation to target cells (Vandal et al., 2003 Kerkhoff et al., 1999 Eue and Sorg, 2001). 

Leukocyte Recruitment into the Lungs as Parameter to Monitor Infection... 

Platelets are considered as the key factors in arterial thrombosis recent studies indicate that they have an important regulatory role as the source of inflammatory mediators and directly initiate (Fig. 8) an inflammatory response of the vessel wall. Platelet and leukocyte recruitment on subendothelial cells is the early mechanism of vascular inflammatory damage. After vascular injury denudation of the endothelium and platelet adhesion, other blood cells are recruited erythrocytes release ADP and leukocyte infiltration occurs by their... 

As with atherosclerosis itself, recruitment of inflammatory cells is now recognized as an essential step in the pathogenesis of neointima formation in humans (I 1,12). In various animal models, reduction of leukocyte recruitment by selective blockade of adhesion molecules significantly reduced neointima formation and restenosis (13-16). Recent studies also concluded a role of pre-existing inflammation within the... 

May AE, Kanse SM, Lund LR, Gisler RH, Imhof BA, Preissner KT. Urokinase receptor (CD87) regulates leukocyte recruitment via beta 2 integrins in vivo. J Exp Med 1998 188(6) 1029-1037. 

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