Does tuberculin skin testing (TST) boost in vitro measures of TB-specific cell mediated immunity?
Weissman DN; Khaled G; Nash E; Bryant J; Henry S; Shi J; D'Amato J; Pisani M; Janotka E; Edberg S; O'Connor P; Russi M; Cain H; Tanoue L; Friedman LN
Am J Respir Crit Care Med 2003 Apr; 167(7):A866
A new FDA-cleared test for latent M. tuberculosis (TB) infection, Quantiferon-TB (QF), measures TB-induced secretion of interferon-gamma (IFN) by peripheral blood cells in vitro. We questioned whether TST responses could be enhanced by TST placement in individuals that were ultimately TST-negative by two-step testing. We analyzed 9 subjects with past medical histories of TST reactivity who were subsequently negative on two-step TST testing. Blood was obtained for QF at baseline and at the time of second TST. Using recommended strategies for interpretation, no QF tests were positive either at baseline or on repeat testing. Three initial QF and 2 repeat QF tests were scored as negative due to a requirement that IFN secretion stimulated by M. avium antigen be no more than 10% greater than TB antigen-induced IFN secretion even though other requirements for test positivity were achieved. Mean levels of IFN secretion to TB antigen expressed either as absolute units or as percentage of mitogen-induced secretion did not significantly increase on repeat testing. In this population, placement of a TST did not enhance subsequent QF responses. The sensitivity of QF for detecting immunity to TB may be decreased by current guidelines for interpretation of reactivity to M. avium antigen.
Skin-tests; In-vitro-studies; Blood-cells; Blood-sampling; Blood-tests; Antigens; Infectious-diseases
Abstract; Conference/Symposia Proceedings
Disease and Injury: Infectious Diseases
American Journal of Respiratory and Critical Care Medicine, 2003 International Conference, The American Thoracic Society, Seattle, WA, May 16-21, 2003
Milford Hospital, Milford, Connecticut