LEUKOCYTE ADHESION DEFICIENCY IN A DUTCH HOLSTEIN CALF - A CASE WITH A CLEAR-CUT FAMILY HISTORY

A leukocyte adhesion deficiency characterized by recurrent (predominan tly bacterial) infections, lack of extravascular polymorphonuclear leu kocyte(PMN) and pus formation has been described first in humans and t hen in dogs, and recently also in cattle. Because of important clinica l similarities, a unitary explanation for the leukocyte adhesion defic iency (LAD) syndrome in mammals is proposed, inasmuch that an intrinsi c leukocyte defect (i.e. mutations in genes encoding the common CD18 s ubunit), is thought to cause the disease. However, thus far, the hallm ark of such intrinsic leukocyte defects, notably their heritability (o r familial incidence), has not (yet) been unequivocally demonstrated. This is the first report to describe the occurrence of four Dutch bovi ne LAD (BLAD) cases with the clearest familial clustering observed to date. The diagnosis was based on the clinical features of very poor th riving, in general, of the calves, hyperneutrocytosis without apprecia ble left shift, and the absence of PMN CD11a, or CD11b, or CD11c using monoclonal antibodies (mAb) and/or Concanavalin A binding activity of PMN lysates in immunoblots. Interestingly, a familial clustering was observed also for below-normal PMN CD11c expression. Thus, a cow with low CD11c expression (50.4%) and delivering three of the study BLAD ca lves, also had a healthy descendant with low (44.9%) PMN CD11c express ion. These findings suggested the possibility that both subnormal expr ession and lack of PMN CD11 expression are inheritable factors in catt le. Furthermore, a large prospective study using the present mAb for s electing relatives expressing the complete spectrum (0 to greater-than -or-equal-to 90%) of PMN CD11/CD18 expression would create a comprehen sive study population for understanding both the role of genetic facto rs and of survival strategies in BLAD.