Analysis of infectious complications in paediatric autoimmune neutropenia: a French nationwide retrospective cohort study

BACKGROUND: Autoimmune neutropenia (AIN) is the main cause of chronic neutropenia in children, but its infectious consequences remain poorly studied. The primary objective of this study was to evaluate infectious events leading to emergency department or hospital admissions during the first 2 years following the diagnosis of AIN in children. METHODS: We performed a retrospective, multicentre analysis of medical records from 21 French university hospitals of patients aged under 18 years diagnosed with AIN with positive antineutrophils autoantibodies. We collected data on emergency room visits and hospitalisations in the 2 years following diagnosis, causes of these events, microbiology results, management and outcome. RESULTS: One hundred and sixty-eight patients were enrolled. Median age at diagnosis of AIN was 13 months. AIN was predominantly diagnosed during an infectious episode (n=120, 71%). In the 2 years of follow-up after diagnosis, 248 events of emergency room visits and/or hospitalisations were reported (0.77 per patient-year). The most frequent diagnoses were common childhood viral or bacterial infections. The incidence rate of severe infections was 0.003 per patient-year. Despite the predominance of viral infections, 177 episodes (71%) led to hospitalisation and 166 (68%) to the initiation of antibiotic therapy, for a median duration of 7 days (IQR 3-10). CONCLUSION: The risk of severe infections in children with AIN is low. During follow-up, we suggest being attentive to signs of severity during fever, particularly in children over 3 years of age and/or with other immunological comorbidities but not proposing systematic hospitalisation or additional antibiotic therapy.