title: Latent and subclinical tuberculosis in HIV infected patients: a cross-sectional study.
abstract: BACKGROUND
  HIV and tuberculosis (TB) are commonly associated. Identifying latent and asymptomatic tuberculosis infection in HIV-positive patients is important in preventing death and morbidity associated with active TB.
  
  
  METHODS
  Cross-sectional study of one time use of an interferon-gamma release assay (T-SPOT.TB - immunospot) to detect tuberculosis infection in patients in a UK inner city HIV clinic with a large sub-Saharan population.
  
  
  RESULTS
  542 patient samples from 520 patients who disclosed their symptoms of TB were tested. Median follow-up was 35 months (range 27-69). More than half (55%) originated from countries with medium or high tuberculosis burden and 57% were women. Antiretroviral therapy was used by 67%; median CD4 count at test was 458 cells/μl. A negative test was found in 452 samples and an indeterminate results in 40 (7.4%) but neither were associated with a low CD4 count. A positive test was found in 10% (50/502) individuals. All patients with positive tests were referred to the TB specialist, 47 (94%) had a chest radiograph and 46 (92%) attended the TB clinic. Two had culture-positive TB and a third individual with features of active TB was treated. 40 started and 38 completed preventive treatment. One patient who completed preventive treatment with isoniazid monotherapy subsequently developed isoniazid-resistant pulmonary tuberculosis. No patient with a negative test has developed TB.
  
  
  CONCLUSIONS
  We found an overall prevalence of latent TB infection of 10% through screening for TB in those with HIV infection and without symptoms, and a further 1% with active disease, a yield greater than typically found in contact tracing. Acceptability of preventive treatment was high with 85% of those with latent TB infection eventually completing their TB chemotherapy regimens. IGRA-based TB screening among HIV-infected individuals was feasible in the clinical setting and assisted with appropriate management (including preventive treatment and therapy for active disease). Follow-up of TB incidence in this group is needed to assess the long-term effects of preventive treatment.
authors.affiliation: Department of Sexual Health, Homerton University Hospital, Homerton Row, London E9 6SR, United Kingdom. meaghan.kall@hpa.org.uk
authors.forename: Meaghan M
authors.initials: MM
authors.lastname: Kall
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Coyne
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Garrett
authors.forename: Aileen E
authors.initials: AE
authors.lastname: Boyd
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Ashcroft
authors.forename: Iain
authors.initials: I
authors.lastname: Reeves
authors.forename: Jane
authors.initials: J
authors.lastname: Anderson
authors.forename: Graham H
authors.initials: GH
authors.lastname: Bothamley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000379:methods; D055985:Latent Tuberculosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D006113:United Kingdom / Q000453:epidemiology; D014505:Urban Population; D055815:Young Adult