Differential diagnosis and clinical course of autoimmune neutropenia in infancy: comparison with congenital neutropenia.
OBJECTIVE
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 1-GIFT and immunoblotting. An antibiotic (sulfamethoxazole-trimethoprim) was given to 15 patients for prophylaxis. G-CSF was given to only one infectious patient.


CONCLUSIONS
A combination of diagnostic tests for the detection of granulocyte-specific autoantibodies 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.
Taniuchi
S
S
Department of Paediatrics, Kansai Medical University, Moriguchi, Osaka, Japan. taniuchi@takii.kmu.ac.jp
Masuda
M
M
Hasui
M
M
Tsuji
S
S
Takahashi
H
H
Kobayashi
Y
Y
D000890:Anti-Infective Agents / Q000627:therapeutic use; D001327:Autoimmune Diseases / Q000175:diagnosis*; D004359:Drug Therapy, Combination; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D019084:Fluorescent Antibody Technique, Indirect; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009503:Neutropenia / Q000151:congenital / Q000175:diagnosis* / Q000276:immunology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use
D000890:Anti-Infective Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination