- Baseline fever > 38.5 C if caused by an occult opportunistic infection or neoplasm and requiring continuous treatment with excluded medications. If the evaluation for infection is unrevealing, the patient may be entered after the evaluation is completed but while mycobacterial cultures are still pending. Patients with a history of unexplained fever > 38.5 C should be evaluated as above and/or be afebrile (T < 38.0 C) for 2 weeks prior to study entry.