P1556: evaluation of the usefulness of interferon-gamma release assay for the detection of latent mycobacterium tuberculosis infections in patients who underwent hematopoietic stem cell transplantation

Topic: 30. Infections in hematology (incl. supportive care/therapy) Background: Tuberculosis (TB) is still a major global public health problem. The likelihood of developing the active disease is much higher in frail patients, such as those with hematopoietic stem cell transplantation (HSCT). Patients undergoing HSCT have severe and prolonged immunodeficiency due to underlying hematologic malignancies, chemo- and immunosuppressive therapy, and graft-versus-host disease, and are generally considered to be at higher risk for active TB or reactivation of latent TB infections. Aims: The aim of this study was to evaluate the occurrence of active TB in patients who received a QuantiFERON test for the detection of latent TB infection. Methods: This is a retrospective observational cohort study, including all adult patients (>18 years old) with hematopoietic malignancies who underwent HSCT. In total, 201 patients who received an interferon-gamma release assay and underwent auto- or allogeneic hematopoietic stem cell transplantation between September 2010 and December 2021 were recruited to determine the usefulness of latent TB infection screening tests. Results: A total of 201 patients, 96 (47.8%) autologous and 105 (52.5%) allogeneic stem cell transplants, underwent QuantiFERON test screening: 148 (51.0%) were negative, 17 (5.9%) indeterminate, and 36 (12.4%) positive. Most of the enrolled patients were male (58.7%) with a median age of 54 years old (range, 19 ~ 69 years old). The most common hematologic malignancy affecting patients before HSCT was acute myeloid leukemia (36.6%), followed by multiple myeloma (14.2%), non-Hodgkin lymphoma (13.9%), and acute lymphoblastic leukemia (12.4%). The QuantiFERON screening test was performed within one month before HSCT. There was no difference in test positive rates between men and women. However, the positive rate was statistically significantly higher in elderly patients (p=0.001). Only 20% of the patients whose test was QuantiFERON test positive took isoniazid prophylaxis, and none of them progressed to active TB over a median follow-up period of 40.4 months. Active TB recurrence did not occur even in 80% of QuantiFERON test-positive who did not take isoniazid, also. Summary/Conclusion: In conclusion, 12.4% of our HSCT population had latent TB infection, only 20% of them received isoniazid prophylaxis. There were no cases of active TB progression in a cohort of 201 patients who underwent HSCT from 2010 to 2021. Keywords: Tuberculosis, Hematopoietic cell transplantation, Interferon gamma