Differential diagnosis and clinical course of autoimmune neutropenia in infancy: Comparison with congenital neutropenia

Abstract

Aim: Autoimmune neutropenia in infancy (AIN) is caused by granulocyte-specific autoantibodies. Clinical presentation and diagnosis have not been well studied, resulting in cumbersome diagnostic investigations and unnecessary treatment such as granulocyte colony-stimulating factor (G-CSF) therapy. Methods: Clinical, laboratory and immunological data of 18 infants with AIN were evaluated. Granulocyte-specific autoantibodies were detected by the direct granulocyte immunofluorescence test (D-GIFT), indirect granulocyte immunofluorescence test (I-GIFT) and immunoblotting. Results: The average age of onset and resolution of neutropenia in AIN was 7.4 ± 3.4 mo (mean ± SD) and 20.4 ± 4.9 mo, respectively. Sixteen of the 18 patients presented with mild infectious symptoms; the other 2 patients were detected by chance and presented with no infectious symptoms. D-GIFT was positive in all patients, and I-GIFT was positive in 17 of these 18 patients. Most patients showed preferential binding to neutrophils from NA(1 + 2-)-phenotyped donors by I-GIFT and immunoblotting. An antibiotic (sulfamethoxazole-trimethoprim) was given to 15 patients for prophylaxis. G-CSF was given to only one infectious patient. Conclusion: A combination of diagnostic tests for the detection of granulocyte-specific auto-antibodies was useful in diagnosing AIN, thus avoiding unnecessary investigations. Continuous treatment with G-CSF was not necessary for prophylaxis, even if neutrophil counts were extremely low.