title: The incidence of tuberculosis in drug users with small tuberculin reaction sizes.
abstract: METHODS
  In persons infected with the human immunodeficiency virus (HIV), a decreased tuberculin reaction cut-point of > or = 5 mm induration is recommended.
  
  
  OBJECTIVE
  To determine tuberculosis risk in non-anergic HIV-infected persons with 5-9 mm tuberculin reactions.
  
  
  METHODS
  A prospective study with semi-annual tuberculin and anergy testing, HIV antibody and T cell subset assays, and active surveillance for tuberculosis.
  
  
  RESULTS
  Participants were 572 HIV-seronegative and 241 HIV-seropositive non-anergic drug users. No tuberculosis occurred in HIV-seronegative persons. Tuberculosis incidence among HIV-seropositive drug users was 3.3, 7.7, 0, and 0.34 per 100 person-years in those with tuberculin reaction sizes of > or = 10 mm, 5-9 mm, 1-4 mm, and 0 mm, respectively, and was significantly increased in persons with 5-9 mm induration compared with those with 0-4 mm induration (rate ratio 27.7, 95%CI 2.9-268). Among persons with reaction sizes of 5-9 mm, tuberculosis occurred exclusively in those with CD4+ lymphocyte counts <500/mm3 at the time of their 5-9 mm tuberculin reactions.
  
  
  CONCLUSIONS
  HIV-infected persons with tuberculin reaction sizes of 5-9 mm are at increased risk for tuberculosis compared to non-anergic persons with smaller (0-4 mm) reaction sizes. However, this increased risk may be limited to those with low CD4+ lymphocyte counts at the time of tuberculin testing.
authors.affiliation: Department of Medicine, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx, New York 10467, USA. RKlein@montefiore.org
authors.forename: R S
authors.initials: RS
authors.lastname: Klein
authors.forename: M N
authors.initials: MN
authors.lastname: Gourevitch
authors.forename: R
authors.initials: R
authors.lastname: Teeter
authors.forename: E E
authors.initials: EE
authors.lastname: Schoenbaum
mesh_terms: D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D017635:Clonal Anergy / Q000276:immunology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000276:immunology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000276:immunology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology* / Q000276:immunology