<unk>  (AIN) is a form of<unk>  which is most common in infants and young children where the body identifies the neutrophils as enemies and makes antibody to destroy them. Primary<unk> , another name for<unk> , is an autoimmune disease first reported in 1975 that primarily occurs in infancy. In<unk> , the immune system produces autoantibodies directed against the neutrophilic protein antigens in white blood cells known as granulocytic neutrophils, granulocytes, segmented neutrophils, segs, polysegmented neutrophils, or polys. These antibodies, IgG antibodies, destroy granulocytic neutrophils. Consequently, patients with<unk>  have low levels of granulocytic neutrophilic white blood cells causing a condition of<unk> .<unk>  causes an increased risk of infection from organisms that the body could normally fight easily. Primary<unk>  has been reported as early as the second month of life although most cases are diagnosed in children between 5 and 15 months of age. Girls have a slightly higher risk of developing AIN than boys as well as do people of Caucasian background. In<unk>  discovered at birth or shortly after birth, a diagnosis of allo-immune<unk>  (from maternal white blood cell antibodies passively transferred to the infant) is more likely. In infants<unk>  is defined by absolute neutrophil counts less than 1000/uL. After the first year of life<unk>  is defined by absolute counts less than 1500/uL.<unk>  may be primary in which it is the only blood abnormality seen. In secondary<unk> , other primary conditions occur, including other autoimmune diseases, infections, and cancers.<unk>  is considered chronic when it persists for more than 6 months.
Autoimmune neutropenia
Severe congenital neutropenia
Bare lymphocyte syndrome
Diffuse infiltrative lymphocytosis syndrome
Myelodysplastic syndrome
Leukocyte adhesion deficiency
Autoimmune lymphoproliferative syndrome
Lymphocyte-variant hypereosinophilia