 For this purpose, twenty tuberculosis patients will start on a standard dose of MFX 400 mg once daily. After 8 days the dose will be increased to 600 mg once daily and on the 15th day of treatment, the dose of MFX will be escalated to 800 mg. In patients who have been treated with rifampicin RIF in the past three weeks prior to start of MFX treatment an additional washout period of 3 weeks to reduce the rifampicin induced enzymatic activity will precede the dose escalation. 