Elevated autorosette formation by lymphocytes of dogs affectd with cyclic neutropenia (CN)

Abstract

Cyclic neutropenia (CN) is an inherited disorder characterized by regularly recurring episodes of neutropenia in humans and Gray Collie dogs. Early thymic hypotrophy and lymphoid exhaustion in the CN dogs suggests there may be a lymphoid cell differentiation defect. Later manifestations of CN in dogs include arthritis, anaemia, glomerulone-phritis, and amyloidosis which are often associated with autoimmune diseases. Several Coombs' antiglobulin tests were performed and did not detect autoantibodies, however, peripheral blood lymphocytes from CN dogs formed rosettes with their own erythrocytes while in normal dogs such rosettes were extremely rare. Furthermore, when lymphocytes from CN dogs were rosetted with erythrocytes from normal dogs, the numbers of allogeneic rosettes were comparable to those formed with autologous erythrocytes. These results suggest strongly that the rosetting lymphocytes are specific for common erythrocyte surface components. Although the physiological importance of the autorosetting phenomenon is not known, the frequency of autorosette formation in CN dogs, as reported here, suggests that it may be an early indication of developing autoimmune activity.