Objectives: progression from latent tuberculosis infection (LTBI) to tuberculosis (TB) is higher in children younger than 5 years because of anergy of their immune system. Accurate diagnosis of LTBI is a desiderable goal in achieving effective TB control particularly in young children, because the preventive chemotherapy is effective and relatively safe. Aim of this study was to evaluate the "performance" of a commercially available Interferon-gamma (IFN-gamma) assay [QuantiFERON-TB Gold In-Tube (QFT-IT); Cellestis Ltd., Victoria, Australia] in this vulnerable population. Methods: in a retrospective study, QFT-IT test was performed in 145 young children ≤ 5 years of age, recent close contact of active pulmonary TB during the period April 2007-December 2010. Tuberculin skin test (TST; 5UI Biocine Test PPD; Chiron, Siena) was available only in 112 (77.2%) children. Results: in our pediatric population: mean age was 2.5 ± 1.5 years, 74 (51%) subjects were born in Italy from immigrant families, 9 (6.2%) were BCG-vaccinated. QFT-IT was positive in 24 (16.6%) children, negative in 112 (77.2%) and indeterminate in 9 (6.2%). TST was positive (cut-off  10 mm) in 28 (25%) of 112 evaluated patients. By statistical analysis, TST and QFT-IT showed a fair agreement: 82.9%, k=0.52. Among the discordant results (n=19): 12 (63.2%) children were TST-positive/QFT-IT-negative, of them 7 (58.3%) were BCG-vaccinated. Three (42.9%) of 7 patients TST-negative/QFT-IT-positive had TB and 4 (57.1%) had LTBI. Among 16 children TST-positive/QFT-IT-positive, 10 had clinical diagnosis of active TB and 6 of LTBI. In this group the analysis of IFN-gamma level as continuous variable revealed: 7/10 (70%) children with active pulmonary TB showed high level of IFN-gamma (10 UI/ml) and a TST size ranging from 10 mm to 15 mm; 3/6 (50%) children with a diagnosed LTBI had high IFN-gamma level 10 UI/ml and a TST size of 11-20 mm. Conclusion: these preliminary data suggest and support the potential advantages of using blood test, e.g. QFT-IT, in young children ≤ 5 years for diagnosing LTBI.

Lombardi G, Petrucci R, Dal Monte P, Losi M, Corsini I, Pace A, et al. (2012). Tuberculosis infection in young children: a screening based on skin and blood testing.

Tuberculosis infection in young children: a screening based on skin and blood testing

LOMBARDI, GIULIA;DAL MONTE, PAOLA;PACE, ANTONELLA;LANDINI, MARIA PAOLA
2012

Abstract

Objectives: progression from latent tuberculosis infection (LTBI) to tuberculosis (TB) is higher in children younger than 5 years because of anergy of their immune system. Accurate diagnosis of LTBI is a desiderable goal in achieving effective TB control particularly in young children, because the preventive chemotherapy is effective and relatively safe. Aim of this study was to evaluate the "performance" of a commercially available Interferon-gamma (IFN-gamma) assay [QuantiFERON-TB Gold In-Tube (QFT-IT); Cellestis Ltd., Victoria, Australia] in this vulnerable population. Methods: in a retrospective study, QFT-IT test was performed in 145 young children ≤ 5 years of age, recent close contact of active pulmonary TB during the period April 2007-December 2010. Tuberculin skin test (TST; 5UI Biocine Test PPD; Chiron, Siena) was available only in 112 (77.2%) children. Results: in our pediatric population: mean age was 2.5 ± 1.5 years, 74 (51%) subjects were born in Italy from immigrant families, 9 (6.2%) were BCG-vaccinated. QFT-IT was positive in 24 (16.6%) children, negative in 112 (77.2%) and indeterminate in 9 (6.2%). TST was positive (cut-off  10 mm) in 28 (25%) of 112 evaluated patients. By statistical analysis, TST and QFT-IT showed a fair agreement: 82.9%, k=0.52. Among the discordant results (n=19): 12 (63.2%) children were TST-positive/QFT-IT-negative, of them 7 (58.3%) were BCG-vaccinated. Three (42.9%) of 7 patients TST-negative/QFT-IT-positive had TB and 4 (57.1%) had LTBI. Among 16 children TST-positive/QFT-IT-positive, 10 had clinical diagnosis of active TB and 6 of LTBI. In this group the analysis of IFN-gamma level as continuous variable revealed: 7/10 (70%) children with active pulmonary TB showed high level of IFN-gamma (10 UI/ml) and a TST size ranging from 10 mm to 15 mm; 3/6 (50%) children with a diagnosed LTBI had high IFN-gamma level 10 UI/ml and a TST size of 11-20 mm. Conclusion: these preliminary data suggest and support the potential advantages of using blood test, e.g. QFT-IT, in young children ≤ 5 years for diagnosing LTBI.
2012
22nd European Congress of Clinical Microbiology and Infectious Diseases
Lombardi G, Petrucci R, Dal Monte P, Losi M, Corsini I, Pace A, et al. (2012). Tuberculosis infection in young children: a screening based on skin and blood testing.
Lombardi G; Petrucci R; Dal Monte P; Losi M; Corsini I; Pace A; Richeldi L;Bernardi F; Landini MP
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/393713
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