lewis-x-antigen and Asthma

Asthma and COPD are chronic inflammatory conditions that affect hundreds of millions of patients worldwide. New therapeutics are desperately needed, especially those that target the underlying causes and prevent disease progression. Although asthma and COPD have distinct etiologies, both are associated with reduced airflow caused by excess infiltration of inflammatory cells into healthy lung tissues. As selectin-mediated adhesion of leukocytes to the vascular endothelium is a key early event in the initiation of the inflammatory response, selectin inhibition is thought to be a good target for therapeutic intervention. Three known selectins are expressed in distinct subsets of cells: P-selectin is presented on the surface of activated platelets and endothelial cells, L-selectin is constitutively expressed on leukocytes, and E-selectin synthesis is upregulated in activated endothelial cells. They mediate cell-cell adhesion in the shear flow of the bloodstream via specialized interactions with clusters of oligosaccharides presented on cell surface glycopeptide ligands. The role of selectin-ligand interactions in the inflammatory response has been demonstrated in various animal models, prompting considerable attention from the pharmaceutical industry.Drug discovery efforts have yielded many different classes of selectin inhibitors, including soluble protein ligands, antibodies, oligosaccharides and small molecules. Although many selectin inhibitors have shown activity in preclinical models, clinical progress of selectin-directed therapies has been slow. Early approaches employed carbohydrate-based inhibitors to mimic the natural ligand sialyl Lewis X; however, these compounds proved challenging to develop. Cytel's CY 1503, a complex oligosaccharide, progressed to phase II/III trials for reperfusion injury, but further development was halted when it failed to demonstrate clinical efficacy. Two protein-based selectin inhibitors have reached phase II development. These included Wyeth's recombinant soluble P-selectin ligand, TSI (PSGL-1), which was discontinued after disappointing results in myocardial infarction trials and Protein Design Labs' humanized anti-L-selectin monoclonal antibody, which is currently in development for trauma. Bimosiamose, discovered by Encysive Pharmaceutical and presently being developed by Revotar Biopharmaceuticals, is an 863 g/mol molecular weight dimer with minimal carbohydrate content and is, to date, the leading selectin inhibito

Topics: Animals; Asthma; Hexanes; Humans; Inflammation; Lewis X Antigen; Mannose; Oligosaccharides; P-Selectin; Pulmonary Disease, Chronic Obstructive; Selectins; Sialyl Lewis X Antigen

The response of peripheral neutrophils was studied in 16 patients with allergic asthma after challenge with birch/grass pollen allergen, in order to identify inflammatory markers associated with only the early asthmatic reaction and those associated with both early and late asthmatic reactions. The allergen challenge proceeded until the patients had an early asthmatic reaction with 100% increase in specific airway resistance. Bronchoconstriction after allergen challenge was monitored hourly over 9 h and finally after 18 h, by measurement of the forced expiratory volume in 1 s. Seven patients had a late reaction, defined as a decrease in forced expiratory volume in 1 s of more than 15%. Blood samples were taken before and 18 h after challenge. After allergen challenge (18 h) the blood concentration of neutrophils in patients with a late asthmatic reaction was 1.4 times higher than before challenge and there was a tendency for increased Fc gamma receptor-mediated chemiluminescence. Lewis X-antigen (CD 15), which is associated with endothelial adhesion and extravasation, significantly decreased at the same time. Neutrophils were incubated with the tetrapeptide arginine-glycine-aspartate-serine before and 18 h after allergen challenge. Both patient groups showed an increased Fc gamma receptor-mediated chemiluminescence and a decreased Fc gamma receptor membrane expression following allergen challenge, suggesting a preactivation. In conclusion, patients with a dual asthmatic reaction show a sustained primed inflammatory response and primed neutrophils compared with patients with only an early reaction when measured after the decline of clinical symptoms provoked by allergen challenge.

Topics: Adult; Asthma; Bronchial Provocation Tests; Female; Humans; Leukocyte Count; Lewis X Antigen; Luminescent Measurements; Male; Middle Aged; Neutrophils; Pollen; Receptors, IgG; Time Factors

Serum levels of sialyl SSEA-1 antigen, a carbohydrate antigen, were measured by radioimmunoassay in 142 patients with nonmalignant lung diseases. In 20 of 41 patients with fibrosing lung disease, either idiopathic or associated with collagen disease, the serum sialyl SSEA-1 levels were abnormally elevated. In patients with other lung diseases, the serum levels were almost within normal limits, less than 38.0 units/ml. In fibrosing lung disease the serum levels ranged from 13.8 to 147.0 units/ml and were largely concurrent with the degree of disease activity. The therapeutic effects of corticosteroid, which were evaluated with clinical-radiographic-physiologic scores and survivals in the patients with elevated serum levels, were significantly lower than those of the patients with the normal range of antigen levels. An immunohistochemical study performed on autopsied lungs from five patients with fibrosing lung disease indicated that the antigen was selectively expressed in the pulmonary epithelial cells that covered the remodeling alveolar septi in the lungs. No antigen was detectable by immunostaining in normal pulmonary epithelium among five normal lungs. From these findings, it is thought that the elevated levels of serum sialyl SSEA-1 may be derived from proliferating epithelial cells that were dominant in the late stage of fibrosing lung disorders. The measurements of serum sialyl SSEA-1 in patients with fibrosing lung disease may be clinically useful in establishing the degree of disease activity that has an influence on patient prognosis and therapeutic response.

Topics: Adrenal Cortex Hormones; Antibodies, Monoclonal; Asthma; Humans; Immunohistochemistry; Immunoradiometric Assay; Lewis X Antigen; Lung; Pneumonia; Prognosis; Pulmonary Emphysema; Pulmonary Fibrosis