BCAM and infection: During physiological stresses, e.g. infections, hypoxia, and dehydration, hemoglobin S (HbS) polymerizes, causing erythrocytes to adopt a sickle morphology and become more rigid, with the consequent expression of various cellular adhesion molecules, e.g. α4β1 [6] and Lu/BCAM [7] that may facilitate the physical interaction of the sickle erythrocytes with endothelium.