title: Immune correlates of acute Mycobacterium tuberculosis infection in household contacts in Kampala, Uganda.
abstract: To determine immunologic and epidemiologic correlates of acute Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis cases, we performed a prospective, community-based cohort study of index cases and their household contacts in Kampala, Uganda. Contacts were evaluated for tuberculin skin test (TST) conversion over two years. Interferon-gamma expression was measured using a whole blood assay after stimulating with M. tuberculosis culture-filtrate. In 222 contacts with a TST less than 5 mm at baseline, the one-year rate of TST conversion was 27%. The TST conversion was associated with the infectiousness of the index case and proximity of contact. Interferon-gamma levels at baseline were greater among TST converters compared with those who did not convert. The risk of TST conversion increased four-fold as the baseline interferon-gamma increased 10-fold, but only in contacts with BCG vaccination. In household contacts of tuberculosis, interferon-gamma responses to non-specific mycobacterial antigens may be used to make an early diagnosis of tuberculosis infection, especially in resource-limited settings where bacille Calmette-Guérin vaccination is commonly used.
authors.affiliation: Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA. ccw@case.edu
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Whalen
authors.forename: Allan
authors.initials: A
authors.lastname: Chiunda
authors.forename: Sarah
authors.initials: S
authors.lastname: Zalwango
authors.forename: Lorna
authors.initials: L
authors.lastname: Nshuti
authors.forename: Edward
authors.initials: E
authors.lastname: Jones-Lopez
authors.forename: Alphonse
authors.initials: A
authors.lastname: Okwera
authors.forename: Christina
authors.initials: C
authors.lastname: Hirsch
authors.forename: Pierre
authors.initials: P
authors.lastname: Peters
authors.forename: W Henry
authors.initials: WH
authors.lastname: Boom
authors.forename: Roy D
authors.initials: RD
authors.lastname: Mugerwa
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000032:analysis* / Q000096:biosynthesis; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011446:Prospective Studies; D012307:Risk Factors; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology* / Q000276:immunology*; D014454:Uganda / Q000453:epidemiology
chemical_list: D007371:Interferon-gamma