BACKGROUND: Reactivation of a latent Mycobacterium tuberculosis infection in immunocompromised individuals is associated with significant morbidity and mortality. The limited sensitivity of the established tuberculin skin-test in identifying latently infected patients on immunosuppressive drug therapy represents a major obstacle to better tuberculosis control after transplantation. METHODS: In this study, a quantitative flow-cytometric whole-blood assay and the skin-test were comparatively evaluated towards both diagnostic power and practicability in 117 long-term renal transplant recipients (age 53.1+/-14.8 years; 7.0+/-5.0 years after transplantation) in a low-prevalence region. RESULTS: Among the aforementioned renal transplant recipients, a high proportion (52.14%) had purified protein-derivative (PPD)-specific T-cell-immunity in vitro. Despite immunosuppression, prevalence as well as median frequencies of PPD-specific T-cells (0.22%; >0.05-4.71%) were as high as previously reported for immunocompetent individuals and haemodialysis patients. In contrast to in vitro testing, skin testing was less practicable in an ambulatory setting. Moreover, skin-test reactivity was significantly reduced as only 50.0% of patients with PPD-reactivity in vitro were skin-test positive. T-cell reactivity towards early secretory antigenic target-6 (ESAT-6), a protein specific for M. tuberculosis but absent from the bacillus Calmette-Guerin BCG-vaccine strain, was found in 52.9% of all individuals with PPD-reactivity in vitro. CONCLUSIONS: In conclusion, the whole-blood assay reveals a high prevalence of latent tuberculosis infection in renal transplant recipients. It may represent a valuable alternative to skin testing as the test result is not adversely affected by immunosuppression. Moreover, reactivity towards ESAT-6 allows the distinction of a latent infection from BCG-induced reactivity. The assay is well-suited for use in screening programmes and may facilitate the management of tuberculosis infection in immunocompromised individuals.
BACKGROUND: Reactivation of a latent Mycobacterium tuberculosis infection in immunocompromised individuals is associated with significant morbidity and mortality. The limited sensitivity of the established tuberculin skin-test in identifying latently infectedpatients on immunosuppressive drug therapy represents a major obstacle to better tuberculosis control after transplantation. METHODS: In this study, a quantitative flow-cytometric whole-blood assay and the skin-test were comparatively evaluated towards both diagnostic power and practicability in 117 long-term renal transplant recipients (age 53.1+/-14.8 years; 7.0+/-5.0 years after transplantation) in a low-prevalence region. RESULTS: Among the aforementioned renal transplant recipients, a high proportion (52.14%) had purified protein-derivative (PPD)-specific T-cell-immunity in vitro. Despite immunosuppression, prevalence as well as median frequencies of PPD-specific T-cells (0.22%; >0.05-4.71%) were as high as previously reported for immunocompetent individuals and haemodialysis patients. In contrast to in vitro testing, skin testing was less practicable in an ambulatory setting. Moreover, skin-test reactivity was significantly reduced as only 50.0% of patients with PPD-reactivity in vitro were skin-test positive. T-cell reactivity towards early secretory antigenic target-6 (ESAT-6), a protein specific for M. tuberculosis but absent from the bacillus Calmette-Guerin BCG-vaccine strain, was found in 52.9% of all individuals with PPD-reactivity in vitro. CONCLUSIONS: In conclusion, the whole-blood assay reveals a high prevalence of latent tuberculosis infection in renal transplant recipients. It may represent a valuable alternative to skin testing as the test result is not adversely affected by immunosuppression. Moreover, reactivity towards ESAT-6 allows the distinction of a latent infection from BCG-induced reactivity. The assay is well-suited for use in screening programmes and may facilitate the management of tuberculosis infection in immunocompromised individuals.
Authors: Patricio Escalante; Kirstin J Kooda; Rizwana Khan; San San Aye; Stratos Christianakis; Daniel G Arkfeld; Glenn R Ehresmann; Jens J Kort; Brenda E Jones Journal: Lung Date: 2014-10-16 Impact factor: 2.584
Authors: S S J Lee; K J Chou; I J Su; Y S Chen; H C Fang; T S Huang; H C Tsai; S R Wann; H H Lin; Y C Liu Journal: Infection Date: 2008-12-10 Impact factor: 3.553
Authors: Christof Geldmacher; Alexandra Schuetz; Njabulo Ngwenyama; Joseph P Casazza; Erica Sanga; Elmar Saathoff; Catharina Boehme; Steffen Geis; Leonard Maboko; Mahavir Singh; Fred Minja; Andreas Meyerhans; Richard A Koup; Michael Hoelscher Journal: J Infect Dis Date: 2008-12-01 Impact factor: 5.226