LEUKOCYTE ADHESION DEFICIENCY IN CATTLE AND DOGS - A GENETIC-DEFECT OF THE IMMUNE-SYSTEM

The present knowledge about the bovine leukocyte adhesion deficiency ( BLAD) is reviewed and the first case of this disease in Belgium is rep orted. The disease was first described in 1983, but only in 1990 the e tiology was discovered. The disease is the result of a genetic defect causing an insufficient expression of beta2-integrins on the cell memb rane of leukocytes. These molecules regulate the diapedesis of neutrop hils out of the blood vessels into the tissues, in particular inflamme d tissues. Homozygous BLAD positive calves therefore have an inadequat e resistance against infections. The etiology, pathogenesis, prevalenc e, clinical aspects, pathology, diagnostics and preventive measures ar e described. A brief comparison is made with similar defects namely th e canine leucocyte adhesion deficiency or CLAD in dogs and the leucocy te adhesion deficiency or LAD in man.