Influence of immunosuppressive treatment of Borna Disease in rabbits.

A total of 72 Borna Disease virus infected rabbits were treated with different concentrations of cyclophosphamide, glucocorticoids or both in combination. Comparison with untreated, infected rabbits showed a drastic alteration in the clinical picture, a considerable prolongation of the survival time, and differences in weight and body temperature during the course of the disease. The immunosuppressed animals had no or low amounts of antibodies in the serum and cerebrospinal fluid, but they harbored infectious virus and high amounts of specific antigen in the brain. A quotient of the relative amount of antibodies and antigen never exceeded 0.20 and was significantly lower than in untreated rabbits. Immunohistologically, differences in location and distribution of antigen as compared to positive untreated animals could not be detected. In the immunosuppressed animals perivascular infiltrates were not observed in the different regions of the brain.