[Mantoux intradermal reaction and lymphocyte populations in asymptomatic HIV-seropositive subjects]

Individuals who are infected with human immunodeficiency virus (HIV) are at high risk of developing tuberculosis, probably due to the reactivation of latent infection associated with HIV-induced immunosuppression. Tuberculin skin test is the best diagnostic means to assess a previous tuberculous infection, but this test may be falsely negative in HIV seropositive subjects. To assess the validity of a non-reactive tuberculin skin test in asymptomatic HIV seropositive subject, we performed Mantoux test 5 TU, chest x-ray, HIV serologic tests on 141 asymptomatic prisoners. Determination of lymphocyte subsets in HIV seropositive carriers had already been performed. Chest x-ray film showed no pleuro-pulmonary lesion in any subject. We found 101 HIV seronegative subjects (89 men and 12 women; 30 +/- 6 yrs with 18-39 range; 34 Mantoux reactive and 67 non-reactive) and 40 HIV seropositive individuals (30 men and 10 women; 29 +/- 6 yrs with 21-39 range; 7 Mantoux reactive and 33 non-reactive). By subdividing HIV seropositive subjects in two groups (reactive and non-reactive to tuberculin test) a significant decrease of CD 4 lymphocytes and CD 4/CD 8 ratio was found in HIV seropositive/Mantoux non-reactive group, without changes in total lymphocytes and CD 8 subset. We conclude that: 1) a non-reactive tuberculin skin test cannot be confidently explained in asymptomatic HIV seropositive subjects with a T helper lymphocyte count decrease; 2) T helper cells are important to keep alive delayed hypersensitivity reaction.