1. Determine whether supplementation with L-arginine and/or vitamin D is safe, and results in more rapid improvement in clinical, mycobacterial, immunological, radiological, physiological and functional measures of treatment outcome. We will randomise patients with pulmonary TB to receive, in addition to standard TB therapy, adjunctive arginine, vitamin D and / or placebo in a randomised, double-blind factorial 2x2 design. We will relate serial measurements of plasma concentrations of L-arginine and vitamin D, and immunological responses (pulmonary NO production, T cell function and phenotype) to measures of treatment outcome [mycobacterial (sputum smear clearance and culture conversion), physiological (spirometry), clinical (symptoms and weight), radiological (chest Xray) and functional (six-minute walk test, modified St George Respiratory Questionnaire)].