ACUTE LEUKEMIA AND LATENT TUBERCULOSIS INFECTION IN ITALY: QUANTIFERON-TB TEST SCREENING IN A LOW TUBERCULOSIS INCIDENCE COUNTRY

Abstract

Background and objectives Identification of latent tuberculosis infection (LTBI) is a critical step of tuberculosis surveillance, especially in low incidence countries, and is limited to situations with a higher probability of developing active disease, e.g., patients with hematological malignancies. According to guidelines, in TB non-endemic countries no clear screening program is established at diagnosis for patients with acute leukemia (AL). The primary endpoint of this study was to establish the LTBI incidence in patients with diagnosis of AL using QuantiFERON (QFT)-TB. Secondarily, TB-specific prophylaxis efficacy and safety, and features driving increased risk of LTBI were evaluated. Methods QFT-TB screening was performed before induction, consolidation or during follow-up, in all patients with AL (myeloid and lymphoid), treated at our Institution between October 2019 and August 2023. Results We accrued 62 patients, of whom 7 (11,3%) tested positive, without any symptoms or signs of active TB, and 2 (3,2%) resulted as indeterminate. All positive patients started prophylaxis with isoniazid 300 mg/die, while patients whose test was indeterminate did not receive any prophylaxis. Active TB was excluded by imaging, as well as microscopic, cultural, and molecular examination on bronchoalveolar lavage. During the 46-month period of observation, none of the patients developed TB reactivation. Conclusions In our country, LTBI is not uncommon as expected. Despite the low sample size, 1 out of 10 of our patients had prior TB exposure. This finding suggests implementing TB screening in the pre-treatment setting, particularly in a time when more numerous active treatments are becoming available also for patients ineligible to intensive chemotherapy.

Keywords

• Acute Leukemia
• tubercolosis
• latent tuberculosis infection
• prophylaxis
• Acute Myeloid Leukemia
• Acute Lymphoblastic Leukemia