Tuberculosis outbreak in rhesus monkeys immunosuppressed with antithymocyte globulin.

Tuberculosis lesions were found in necropsied monkeys used in studies involving immunosuppression. Correlations were made between the demonstration of reduced numbers of circulating T cells, the duration of allograft survival and the appearance of T cell-dependent tuberculin sensitivity. The immunosuppressed state of these monkeys may have resulted in false tuberculin reactions. The report confirms the necessity for sequential tuberculin tests on rhesus monkeys prior to their being used in experiments.