Infection in children with acute lymphoblastic leukaemia

Infection is the commonest cause of morbidity and mortality in children undergoing treatment for acute lymphoblastic leukaemia (ALL). This population-based study aimed to describe the prevalence of microbiologically documented infections in children with ALL during different phases of treatment, and to examine associations with patient characteristics and treatment-related variables. 267 patients diagnosed with ALL aged between 1-17 years were identified from the Haematological Malignancy Research Network over a near 13 year period (2004-2017). Their microbiological samples, including blood cultures, respiratory samples and samples sent for fungal testing, were analysed across different phases of treatment. 254/267 (95.1%) patients had at least one microbiological sample taken during treatment (5,240 samples), and 230/254 (90.5%) of these had at least one positive sample (1,171 positives). Among positive samples, respiratory viral pathogens were identified across all phases of treatment. In the few positive blood culture samples, there was a predominance of Gram +ve bacteria. During induction, females, those diagnosed under the age of ten years, and those treated under more intensive regimens were more likely to have at least one positive microbiological sample. This was also the case for patients that were treated under regimen B during consolidation (intensive but relatively short), and those diagnosed under the age of ten years during delayed intensification. During maintenance, patients who lived in more deprived areas had higher rates of positive blood cultures. To date, this is the first UK cohort of patients with ALL treated in a paediatric setting to report on microbiological history during treatment. Demonstrating that some patient groups are more at risk than others, and showing microbial differences within and between patients across the various treatment phases, this research highlights the importance of taking a longitudinal approach and indicates several key areas for future research.