The purpose of this study is to identify differences in TB specific immune responses among immunosuppressed patients latently infected with TB and patients with active TB.

Immunosuppressed patients latently infected with TB are at higher risk of developing active TB than patients with normal immune functions. Especially two patient categories are at risk: HIV positives and patients receiving TNF-a blocking medication. Existing methods of diagnosis and surveillance of latent TB infection can not identify who will develop active TB and who can control the infection. There is a need for better understanding of TB specific immune functions,as we believe deficient TB specific immune reactions is a key in reactivation of latent TB infection.

In this study we follow groups of latent TB infected patients with either rheumatoid arthritis or HIV. We follow the patients during treatment with TNF-a blocking medication, HAART treatment or prophylactic TB medication. Results are correlated to patients with active TB, latent TB and healthy controls.

Inclusion Criteria:

• Latent TB infection + rheumatid arthritis
• Latent TB infection + HIV
• Active TB

Exclusion Criteria:

• Age < 18yrs
• Pregnancy
• Patients not able to understand the given information