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
×
10
9
/L vs.
8.7
×
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.
Mixed-phenotypic acute leukemia: cytochemically myeloid and phenotypically early T-cell precursor acute lymphoblastic leukemia