Early T-Cell Precursor Leukemia Has a Higher Risk of Induction-Related Infection among T-Cell Acute Lymphoblastic Leukemia in Adult

Abstract

Background. Infections are an important cause of morbidity and mortality for acute lymphoblastic leukemia (ALL). However, the reports regarding risk factors of induction-related infection are roughly unknown/limited in adult T-ALL during induction chemotherapy. Methods. We performed a retrospective cohort study for the prevalence and risk predictors of induction-related infection among consecutive T-ALL patients ( $N=97$ ) enrolled in a PDT-ALL-LBL clinical trial. Of 97 patients with T-ALL enrolled in the trial, 46 were early T-cell precursor (ETP) ALL and 51 were non-ETP ALL. Results. When compared with non-ETP, ETP ALL subtype was characterized with lower neutrophil count ( $1.35\times {10}^9$ /L vs. $8.7\times {10}^9$ /L, $P<0.001$ ) and lower myeloid percentage in the bone marrow (13.35% vs. 35.31%, $P=0.007$ ). Additionally, ETP ALL had longer neutropenia before diagnosis ( $P<0.001$ ), as well as during induction chemotherapy ( $P<0.001$ ). Notably, the ETP cohort experienced higher cumulative incidence of clinically documented infections (CDI; 33.33%, $P=0.001$ ), microbiologically documented infections (MDI; 45.24%, $P=0.006$ ), resistant infection (11.9%, $P=0.013$ ), and mixed infection (21.43%, $P=0.003$ ), respectively, than those of the non-ETP cohort. Furthermore, multivariable analysis revealed that T-ALL mixed infection was more likely related to chemotherapy response (OR, 0.025; 95% CI 0.127-0.64; $P=0.012$ ) and identified myeloid percentage as a predictor associated with ETP-ALL mixed infection (OR, 0.915; 95% CI 0.843-0.993; $P=0.033$ ), with ROC-defined cut-off value of 2.24% in ETP cohorts. Conclusions. Our data for the first time demonstrated that ETP-ALL characterized with impaired myelopoiesis were more susceptible to induction-related infection among T-ALL populations.