Latent and active tuberculosis infection in allogeneic hematopoietic stem cell transplant recipients: a prospective cohort study

Tuberculosis (TB) is a major infectious complication in hematopoietic stem cell transplant (HSCT) recipients in countries with high TB prevalence. Identifying and treating latent tuberculosis infection (LTBI) helps to prevent TB reactivation after transplantation. Few studies have compared the tuberculin skin test (TST) with interferon Gamma release assays (IGRA) to diagnose LTBI in HSCT candidates. We compared TST and QuantiFeron TB gold in tube (QTF-GIT) and prospectively evaluated the incidence of active tuberculosis in 126 HSCT candidates and 58 HSCT recipients with chronic GVHD followed at the outpatient clinic. TB was diagnosed by culture in Mycobacteria media and by commercial real-time PCR kit. Considering the positivity of any test, the prevalence of LTBI was 8.7% in HSCT candidates (11 out of 126) and 12.5% in HSCT recipients with chronic GVHD (6 out of 48). QTF-GIT indeterminate results were detected in 2.4% of the HSCT candidates. Fair to good agreement (K > 0.50) between tests was observed in both cohorts. Cumulative incidence of TB was 3% in the GVHD cohort. TB was diagnosed in 2 chronic GVHD recipients, both cases confirmed by positive culture and PCR. None of the 11 patients with LTBI diagnosed pre-HSCT who received INH prophylaxis developed TB.