Autoimmune Neutropenia

Neutropenia is defined by a reduction in circulating polymorphonuclear neutrophils (PMNs) below 1.5 × 109/L, often resulting from autoimmune mechanisms involving the destruction of neutrophils by autoantibodies. Primary autoimmune neutropenia is more common in women and can manifest in infancy, while secondary cases often occur in adults with underlying connective tissue diseases or hematological neoplasms. Clinical presentation varies, and the risk of infections increases with the degree and duration of neutropenia. Laboratory findings include neutropenia, often with anemia, thrombocytopenia, and bone marrow abnormalities. Various serological tests are used to detect anti-neutrophil autoantibodies, with novel techniques like flow cytometry and enzyme-linked immunosorbent assays being developed. Treatment options are limited, with granulocyte colony-stimulating factor (G-CSF) being the primary therapy, but should be restricted to patients with a total absence of PMNs and severe infections.