Patients in this study will receive IL-12 injections under the skin twice a week for one year. They will be taught how to self-administer the drug, but a home care nurse or a physician may also give the injections. The drug dosage will be increased each week to determine the safest and most effective dose for fighting this infection. If intolerable side effects develop at a certain dose, the previous dose level will be used for the next injection. That dose will then be used for the rest of the study, unless unacceptable side effects develop at that level, in which case the dose will again be lowered. Patients will receive an antibiotic against mycobacteria.