Immunosuppression with cyclosporine during the incubation period of experimental woodchuck hepatitis virus infection increases the frequency of chronic infection in adult woodchucks [L'immunosuppression par la ciclosporine pendant la période d'incubation de l'infection expérimentale au virus de l'hépatite de la marmotte augmente la fréquence de l'infection chronique chez les marmottes adultes].

Résumé

The immunosuppressive agent cyclosporine was given to adult woodchucks during acute experimental infection with woodchuck hepatitis virus (WHV). All 17 woodchucks given WHV alone or with a vehicle resolved the infection (i.e., zero chronicity), but when cyclosporine was given throughout the incubation and acute phases of infection (0-12 or 14 weeks, n = 12), the rate of chronic infection increased to 92%. When cyclosporine was given only during the incubation period (0-4 weeks, n = 10) or only during the acute phase of infection (2-12 weeks, n = 9), the rates increased to 50% and 55%, respectively. However, when the drug was given after the acute phase (8-18 weeks, n = 9), the chronic infection rate (11%) did not differ from that in untreated and vehicle controls. Immune responses inhibited by cyclosporine are important in resolution of acute WHV infection and occur mainly during the first 8 weeks. Immunosuppression of these responses for even short intervals during incubation (e.g., 0-4 weeks) increases the risk of chronicity.