A prospective study of positive tuberculin reactions in women with or at risk for HIV-1 infection

We prospectively studied 1310 women with or at risk for HIV- 1 infection to assess subsequent tuberculin reactions in those with ≥10 mm induration. Forty-seven HIV-positive and 57 negative women had tuberculin reactions ≥10 mm induration; reversions to reactions <10 mm occurred in 44% and 46% of those retested, respectively (P = NS). Among seropositives, reversions were associated with lower CD4+ lymphocyte count (P = 0.02). Of a total of 45 subsequent tuberculin tests in seropositive women, only two (4%) resulted in 5-9 mm induration, both at CD4+ counts <500/mm³. Three (30%) of an additional 10 seropositive women with maximal reactions of 5-9 mm induration reported prior tuberculosis exposure, a significantly lower proportion than the 36/47 (77%) with reactions ≥10 mm induration (P < 0.01), but not different than women with maximal reaction sizes <5 mm (219/814, 27%). This study suggests that reversions of ≥10 mm tuberculin reactions to 5-9 mm are rare. In HIV-positive persons, especially those with CD4+ lymphocyte counts ≥500/mm³, reaction sizes of 5-9 mm often may not indicate Mycobacterium tuberculosis infection.