Screening for Latent Tuberculosis Infection in Patients with Hematologic Malignancies Using Interferon-Gamma Release Assays (IGRAS)

Abstract

Background: The development of interferon-gamma release assays (IGRAs) is important in the diagnosis- of latent tuberculosis infection (LTBI). Objectives: The aim of this study was to evaluate the role of QuantiFERON®-TB Gold In-Tube test (QFT-GIT) in detection of LTBI in patient with hematological malignancy and to identify individuals who are at increased risk for the development of tuberculosis (TB). Methodology: the study was conducted on 52 newly diagnosed patients with hematologic malignancies at National Cancer Institute, Cairo University. The interferone- gamma secreted by T-lymphocytes following stimulation by antigens unique to Mycobacterium tuberculosis was measured. The QFT results were evaluated in relation to different clinical and hematologic parameters and outcome after induction therapy. Results: Nine out of 52 cases (17.5%) were positive for QFT. The patients included were 30 males (58%) and 22 females (42%), with a mean age of 42.75±15.39 years. Out of the 52 patients, 21 (40%) were Leukemic, while 31 patient (60%) had lymphoma. Among the QFT positive cases, 6/9 were lymphoma (67%) and 3/9 were leukemic cases (33%). Manifestations of infection were observed in 13/52 (25%) of cases and 55.5% of positive QFT cases (5/9) while positive chest radiological findings were reported in 44.4% of positive QFT cases (4/9). Lymph node enlargement were reported in 6/9 (66.7%) of QFT positive cases. After induction chemotherapy, 8 patients had an unfavorable outcome, 4 of whom were QFT positive. Conclusion: Interferon-Gamma Release Assays (IGRAs) can aid in diagnosing latent tuberculosis infection in patients with hematologic malignancies. This may prevent the spread of infection and identify who would benefit from treatment of latent TB infection.