Prevalence of Latent Tuberculosis in Patients Undergoing Hematopoietic Stem Cell Transplantation and Risk of Disease Activation in an Endemic Population

Abstract

Introduction Latent tuberculosis infection (LTBI) affects one third of the worldOs population. It is well known that patients with immunodeficiency are at a higher risk of developing active tuberculosis (ATBI). Hematopoietic stem cell transplant (HSCT) recipients have and incidence of ATBI 10 to 40 times higher when compared to general population, related to high morbidity and mortality. Objectives Our aim was to determine prevalence of LTBI and incidence of ATBI in recipients and donors of HSCT living in an endemic country. Methods We retrospectively analyzed clinical data of patients that underwent HSCT between January 2010 and December 2016 at our Institution. Results We included 200 patients, 63 allogeneic-HSCT (allo-HSCT) recipients, 74 autologous-HSCT (auto-HSCT) recipients, and 63 HSCT donors. Median age was 36 years (11-68) and 57.5% were male (n=115). Main baseline diagnosis that led to HSCT were: acute leukemia in 27.7%, lymphoma in 23.4%, and monoclonal gammopathy in 20.4% (figure 2). The source of HSCT was peripheral blood (PB) in 83 patients, bone marrow (BM) in 21, and primed-BM in 21 patients. Allo-HSCT donors were matched-related (MRD) in 85.7%, matched unrelated (MUD) in 6.3%, and haploidentical in 9%. All patients were evaluated pre-HSCT with tuberculin skin test (TST) and chest x-ray. Patients with positive TST (n=54) were further evaluated to rule out ATBI with chest-CT (n=54) and smear and culture in either sputum (n=28), gastric fluid (n=16), and urine (n=27), with no positive results. Rates of LTBI were 17% in all-HSCT recipients, 24% in auto-HSCT, and 39% in donors. All patients diagnosed with latent tuberculosis received treatment with isoniazid 300mg for at least 6 months. Interestingly, any patient developed ATBI after transplantation. According to state of residence, most cases were detected in states were lower socioeconomic status and related to migration corridors (Figure 1). Conclusions To our knowledge, this is the first study that evaluates the prevalence of LTBI among HSCT recipients in a Latin American country where TB is endemic. We identified a prevalence of LTBI similar to the estimations of the WHO, however, unlike other published reports from developed and developing countries we have no incidence of active tuberculosis in our population despite Mexico is an endemic country. Figure 1 Cases distribution according patients state of residence.