Determination of soluble/circulating L-selectin could provide more detailed insights into the pathological modifications during various diseases: - allergy: L-selectin expression is down-modulated on eosinophils recovered from bronchoalveolar lavage fluid after allergen provocation. - bronchoalveolar lavage (BAL): BAL transiently promotes PMN/monocyte activation and recruitment to the bronchoalveolar space. The cells respond with a complete shedding of L-selectin when they extravasate from the blood into the bronchoalveolar space. - deep venous thrombosis (DVT): A case can be made for the participation of PMN's in the initiation and propagation of venous thrombosis. Probably via L-selectin leukocytes adhere to areas of veins that serve as sites for initiation of thrombi. - HIV: patients suffering from HIV-infection showed markedly elevated levels of sL-selectin in serum. - insulin-dependent diabetes mellitus (IDDM): serum levels of L-selectin were found to be elevated in IDDM patients and in subjects at risk for developing IDDM. - Kawasaki Syndrome: sL-selectin levels seem to be less than those of normals. - malignant B-cell populations: B-cell chronic lymphocytic leukaemia, hairy cell leukaemia and mantle zone lymphoma are L-selectin positive. - neonatal bacterial infection: in case of intra-uterine infection lymphocytes obtained from cord blood have a diminished L-selectin expression. This is independent of gestational age, birth weight, umbilical artery pH, hematocrit, leukocyte count, absolute neutrophil count, CRP-level or maternal fever . - sepsis: patients suffering from sepsis showed markedly elevated levels of sL-selectin in serum. Vascular endothelial injury observed in overwhelming sepsis may be caused by neutrophil-derived enzymes. Adherence to endothelium is a prerequisite for this process. Measurement of sL-selectin may provide further insights into the interrelationship between neutrophil activation and endothelial damage in gram-negative sepsis. - surgery: patients undergoing cardiopulmonary bypass surgery may develop an acute post-operative capillary leak, due to endothelial injury inflicted by adherent neutrophils. In those patients L-selectin is completely lost in a small but progressively increasing proportion of PMN's, which could be responsible for the endothelial damage.