Procedure:
Chinese children under 18 years of age with neutropenia ≤ 1.5 x
109/L lasting 6 months or more in our single center
were recruited into the study between 2016 to 2018. Patients with
secondary causes of neutropenia were excluded. Blood for anti-neutrophil
antibody and genotyping was taken once at the time of recruitment and
subsequently when neutropenia recovered to ≥ 1.5 x
109/L. A combination of two in-house methods including
GIFT, GAT and commercial kit LABScreenTM multipanel were used for the
detection of antibodies. The age of onset, age of recovery, duration of
neutropenia, gender, serial neutrophil counts, incidence of invasive
infection, use of G-CSF were examined.