BACKGROUND: Severe neutropenia is defined as an absolute neutrophil count (ANC) less than 0.5×109/L, which is known to increase the risk of serious bacterial infections. The aim of this study was to investigate characteristics, etiology and differences between transient and chronic severe neutropenia in children.METHODS: 204 children, who were diagnosed with severe neutropenia at the Ajou University Hospital during a 5-year period, were included in the study. Clinical and laboratory features were analyzed. The patients were classified as having transient severe neutropenia (TSN) if recovery occurred within 6 months of diagnosis, and chronic severe neutropenia (CSN) if the neutropenia persisted for 6 months or more.RESULTS: 184 (90.2%) patients with TSN and 20 (9.8%) patients with CSN were identified. Most of the TSN occurred in patients less than 2 year of age (75.5%) and rarely occurred in patients 5 years or older (5.4%). The most common cause of TSN was infection-related neutropenia (82.6%), and most of the associated infections were respiratory infections (44.6%). Compared to TSN, CSN patients were younger at diagnosis (1.00 vs. 0.71, P < 0.001), had a lower ANC at diagnosis (364.8 vs. 214.9, P < 0.001), lower ANC at nadir (356.0 vs. 50.0, P < 0.001), and higher platelet count (188×10⁹ vs. 308×10⁹, P < 0.001), monocyte count (491.5×10⁶ vs. 832.9×10⁶, P=0.010) and CRP (0.22 vs. 0.85, P=0.036).CONCLUSION: Most of the severe neutropenia occurred in children younger than 2 years of age, and virus infection was the most common cause of TSN.
Bacterial Infections ; Child ; Diagnosis ; Humans ; Monocytes ; Neutropenia ; Neutrophils ; Platelet Count ; Respiratory Tract Infections

BACKGROUND: Children with Down syndrome (DS) have a 10- to 20-fold increased risk of developing leukemia. However, in some patients, leukemia does not become apparent despite significant number of blast cells in the peripheral blood. This condition is called Transient myeloproliferative disorder (TMD), and is a disease entity unique to DS newborns and defined as the morphologic detection of blasts in DS less than three months of age. The present study investigated whether there was a difference between leukemia and TMD, and determined prognostic and risk factors.METHODS: We collected blood samples from 317 patients of 433 DS confirmed patients. We found 18 patients who had blast cells in their peripheral blood.RESULTS: Twelve patients were positive for blasts during the neonate period, and only one patient progressed to leukemia. The other 11 patients were later diagnosed with TMD. Six more patients were later diagnosed with leukemia, therefore, 7 patients were diagnosed with leukemia in total. All patients diagnosed with leukemia had anemia at the time of diagnosis, which was not found in TMD patients. All leukemia patients developed their disease after three months of life. Acute Myeloid Leukemia (AML) patients had additional chromosome mutation to trisomy 21 when they were diagnosed.CONCLUSION: In patients with Down Syndrome, anemia at diagnosis and age of onset could be helpful in distinguishing TMD from acute leukemia. Cancerous mutations in the chromosomes of peripheral and marrow blast cells of Down syndrome patients may foreshadow acute leukemia.
Age of Onset ; Anemia ; Bone Marrow ; Child ; Diagnosis ; Down Syndrome ; Humans ; Infant, Newborn ; Leukemia ; Leukemia, Myeloid, Acute ; Myeloproliferative Disorders ; Risk Factors