 This study is a controlled, open, randomized, multi-center clinical trial. The study was authorized by the Clinical Research Ethics Committee of all participating centers and informed written consent was obtained from all the patients included. The cutaneous anergy was defined by the absence of a reaction 0 mm to skin reactivity tests with tuberculin, Candida albicans, and parotiditis antigens 72 hours after inoculation. The patients were randomzed into one of the following four groups: isoniazid for 6 months 6H, rifampin plus isoniazid for 3 months 3RH, rifampin plus pyrazinamide for 2 months 2RZ or no treatment NT. All of the participating subjects underwent a basal study that included clinical and epidemiological history, chest x-ray, hemogram, analysis of serum creatinine concentrations, uric acid, AST, ALT, alkaline phosphatase, and total bilirubin, as well as a CD4 T-lymphocyte count.During prophylactic treatment, patients were evaluated every 15 days for the first two months and monthly thereafter. At each check-up it was determined whether or not the patient was following the treatment properly and whether there were any adverse effects. Therapeutic completion was defined as taking at least 80 of the total prescribed dosages.Chemoprophylaxis was discontinued whenever a patient requested to do so or for any of the following reasons: appearance of Grade 3 or 4 side effects that could be attributed to the drugs used in the study; increases in AST andor ALT values of three times or more their basal values; development of TB; or diagnosis of any disease that made interruption of the treatment advisable. 