Strategy to Better Select HIV-Infected Individuals for Latent TB Treatment in BCG-Vaccinated Population

Chin-Hui Yang,Hung-Yi Chiou,Wing-Wai Wong,Po-Ren Hsueh,Shu-Hsing Cheng,Say-Tsung Liao,Pei-Chun Chan,Li-Min Huang,Riccardo Manganelli

doi:10.1371/journal.pone.0073069

Abstract

ObjectiveTo evaluate the T-SPOT.TB interferon-γ releasing assay and the tuberculin skin test (TST), for the diagnosis of latent tuberculosis infection(LTBI) and the development of subsequent active tuberculosis, in BCG-vaccinated HIV-infected individuals.MethodsHIV-infected individuals without clinical suspicion of active TB or a past history of TB were enrolled from 1 January 2008 to 30 November 2010. Both T-SPOT.TB test and TST were offered to the participants whom were followed up prospectively until April 30, 2012 for development of TB.ResultsAmong the 909 participants, 25% had positive TST reactions with cut-off point of 5 mm and 15% had positive T-SPOT.TB results. After a median follow-up of 2.97 years, there were 5 cases developed culture-confirmed active TB (all had dual positive TST and T-SPOT.TB results), and the incidence was 0.17 per 100 person-years. The relative risks (RRs) for subsequent active TB in HIV-infected individuals with positive TST results, positive T-SPOT.TB results and dual positive results compared with the risk for individuals with negative results were 40.6 (95% CI 2.1–767.9), 73.9 (95% CI 3.9–1397.7) and 226.5 (95% CI 12.0–4284), respectively. The number needed to treat to prevent one subsequent TB case among patients with a positive TST, a positive T-SPOT.TB and dual positive results was 35, 22 and 8 respectively.ConclusionsAdopting positive results of the TST and T-SPOT.TB to screen LTBI among BCG-vaccinated HIV-infected individuals might be feasible. Number needed to treat for isoniazid preventive therapy could be reduced significantly by using dual positive strategy.

Highlights

HIV-infected individuals have a higher rate of progression from latent tuberculosis infection (LTBI) to active TB than do nonHIV-infected persons, even with the use of effective antiretroviral therapy and the relative risk reached ten-fold [1,2,3,4]
We evaluated the performance of TST and T-SPOT.TB with regard to the development of active TB in participants who did not receive Isoniazid preventive therapy (IPT)
The incidence of active TB among our participants was 0.17/100 person-year (PY); 95% CI, 0.003–0.29/100 PY

Summary

Introduction

HIV-infected individuals have a higher rate of progression from latent tuberculosis infection (LTBI) to active TB than do nonHIV-infected persons, even with the use of effective antiretroviral therapy and the relative risk reached ten-fold [1,2,3,4]. Though free highly active antiretroviral therapy policy reduced mortality rate and the incidence of opportunistic infections in HIV-infected persons, TB along with Pneumocystis carinii pneumonia remained the most common opportunistic infections in PLHIV in Taiwan [10]. Through the implementation of directly observed treatment strategy in 2006, the TB incidence in Taiwan decreased gradually from 73/105 in 2005 to 57/105 in 2010 [11]. With decreasing new TB case number, diagnosis and treatment of LTBI in high-risk populations has become the important strategy in accelerating TB elimination

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Conclusion