Acute respiratory infections in children and adolescents with acute lymphoblastic leukemia

Abstract

Background: Knowledge regarding the incidence, clinical course, and impact of respiratory viral infections in children with acute lymphoblastic leukemia (ALL) is limited.

Methods: A retrospective cohort of patients with newly diagnosed ALL who were treated on the Total Therapy XVI protocol at St Jude Children's Research Hospital between 2007 and 2011 was evaluated.

Results: Of 223 children, 95 (43%) developed 133 episodes of viral acute respiratory illness (ARI) (incidence, 1.1 per 1000 patient-days). ARI without viral etiology was identified in 65 patients (29%) and no ARI was detected in 63 patients (28%). There were no significant associations noted between race, sex, age, or ALL risk group and the development of ARI. Children receiving induction chemotherapy were found to be at the highest risk of viral ARI (incidence, 2.3 per 1000 patient-days). Influenza virus was the most common virus (38%) followed by respiratory syncytial virus (33%). Of 133 episodes of viral ARI, 61% of patients were hospitalized, 26% experienced a complicated course, 80% had their chemotherapy delayed, and 0.7% of patients died. Twenty-four patients (18%) developed viral lower respiratory tract infections (LRTI), 5 of whom (21%) had complications. Patients with viral LRTI had a significantly lower nadir absolute lymphocyte count; were sicker at the time of presentation; and were more likely to have respiratory syncytial virus, to be hospitalized, and to have their chemotherapy delayed for longer compared with those with viral upper respiratory tract infections.

Conclusions: Despite the low incidence of viral ARI in children with ALL, the associated morbidity, mortality, and delay in chemotherapy remain clinically significant. Viral LRTI was especially associated with high morbidity requiring intensive care-level support. Cancer 2016;122:798-805. © 2015 American Cancer Society.

Keywords: immunocompromised; infection; leukemia; pediatric; respiratory virus.

Figure 1. Distribution of Acute Respiratory Illness (ARI) with Viral Etiology per Year

Because prior to October 2007 children received therapy per previous regimen, only one ARI with viral etiology was identified in 2007 and 12 in 2008 as part of this study. In order to obtain an accurate estimate of the frequency of respiratory viral infections each year, additional 75 episodes of ARI with viral etiology that occurred in children with ALL continuing therapy per the previous Total Therapy XV protocol, and thus not enrolled in this study, were also included in Figure 1.

Figure 2

Distribution of the Identified Respiratory Viruses per Month