SUMMARY
Marked differences in bone marrow cellularity were observed between cattle affected with leukocyte adhesion deficiency (lad) and control cattle. The number of nucleated cells in bone marrow was 2.9 to 8.8 times higher in cattle affected with lad, compared with controls. The myeloid-to-erythroid ratio of bone marrow from 3 cattle affected with lad ranged from 2.4 to 12. Deficient CD18 expression on neutrophils isolated from bone marrow of cattle with lad was clearly detected by flow cytometric analysis. Neutrophils from bone marrow of cattle affected with lad appeared round and not flat, after adherence to plastic wells under agarose, whereas neutrophils from bone marrow of clinically normal cattle were firmly spread on the surface of plastic wells. In the chemotaxis under-agarose assay, many pseudopodia were detected on bone marrow neutrophils from clinically normal cattle, but were not detected on bone marrow neutrophils from cattle with lad. Activities of chemotactic movements and phagocytosis of neutrophils isolated from bone marrow of cattle affected with lad were documented to be severely impaired.
