title: The tuberculin skin test in relation to immunological in vitro reactions in BCG-vaccinated healthcare workers.
abstract: The aim was to study the tuberculin skin test in relation to immunological in vitro reactions in bacille Calmette-Guerin (BCG)-vaccinated healthcare workers. The present study was performed in Sweden, a country with a low incidence of tuberculosis, a high BCG vaccination efficacy and high tuberculin conversion rates. BCG-vaccinated healthcare workers (n=381) were tuberculin skin tested. From these, 11 subjects with negative tuberculin reactions (<6 mm) were matched for age and sex with 11 subjects with large positive reactions (> or = 15 mm). Lymphocyte transformation and the production of interferon-gamma (IFN-gamma) were analysed after stimulation in vitro of peripheral blood mononuclear cells with tuberculin purified protein derivative, heat-killed tubercle bacilli and a culture filtrate from tubercle bacilli. In the tuberculin-positive group the lymphocyte transformation response was 2-3 times larger, and IFN-gamma production was 7-10 times larger, than in the tuberculin-negative group (p<0.001). The present results suggest that a positive tuberculin skin test in bacille Calmette-Guerin-vaccinated subjects indicates a stronger immune response of the protective T-helper 1-type than does a negative test. In similar settings, the study supports the traditional practice of regarding the tuberculin skin test in bacille Calmette-Guerin-vaccinated subjects as an indicator of a protective immune response against tuberculosis.
authors.affiliation: Dept of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Göteborg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Fjällbrant
authors.forename: M
authors.initials: M
authors.lastname: Ridell
authors.forename: L O
authors.initials: LO
authors.lastname: Larsson
mesh_terms: D000328:Adult; D001500:BCG Vaccine / Q000276:immunology* / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006282:Health Personnel; D006801:Humans; D066298:In Vitro Techniques; D015994:Incidence; D007371:Interferon-gamma / Q000097:blood; D008213:Lymphocyte Activation; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D011237:Predictive Value of Tests; D013548:Sweden / Q000453:epidemiology; D014373:Tuberculin / Q000276:immunology*; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control*
chemical_list: D001500:BCG Vaccine; D014373:Tuberculin; D007371:Interferon-gamma