Autoimmune and Chronic Neutropenia(Archived)

Neutropenia is defined as a number of neutrophils in the body, a granulated white blood cell type, less than 1500/microliter. It is multifactorial in origin, either by decreased production, sequestration from endothelium and tissues, or increased peripheral destruction. Autoimmune neutropenia (AIN) is a reduced number of neutrophils resulting from increased peripheral destruction by antineutrophil antibodies from autoimmune disorders. These autoantibodies are directed against cell membrane antigens present on IgG Fc receptors. AIN can be considered chronic neutropenia if it lasts more than 3 months and is unrelated to any etiology. Chronic neutropenia can be either idiopathic or involve other etiologies of AIN. AIN is categorized as primary and secondary according to etiology and pathogenesis. The primary form of AIN is dominant in children, and it presents commonly as a hematologic abnormality and bonemarrow hypoplasia. The secondary form of AIN is present in adults as autoimmune disorders, primary immune deficiencies, infections, hematologic malignancies, or drug exposure. AIN is also prevalent in post-transplant patients as well as in some neurological diseases. AIN's clinical manifestations may vary from asymptomatic to life-threatening infections in individuals. In the pediatric population, it can lead to recurring infections, hematologic malignancies, and neuropsychiatric disorders.