Autoimmune neutropenia (AIN) is a frequent cause of chronic neutropenia especially in youngest children. Its diagnosis is established by immunological proof of the autoimmune mechanism. The aim of this study is to better describe this autoimmune process and to show the contribution of bone marrow smears to this diagnosis.
Patients and methods: Ten children, six girls and four boys, were examined between 1990 and 1995. Eight of them had typical AIN, confirmed by the presence of antibodies against neutrophils. Two other patients were included on the basis of bone marrow pictures. Five non-neutropenic children with normal bone marrow smears were chosen as controls. Bone marrow analysis was always performed by the same cytologist according to a reproducible technique.
Results: Six out of ten patients had important features of elective phagocytosis of neutrophils by marrow macrophages (unlike controls) without signs of dysgranulopoiesis or hemophagocytosis. Antibodies against neutrophils were detected in six patients with phagocytosis and in four patients without these cytological features. In two other children presenting the same bone marrow picture and clinical profile, an autoimmune process was probable, even in the absence of antibodies against neutrophils. Some patients had several infections and were given immunoglobulins and/or granulocyte colony-stimulating factor (G-CSF) therapy. The efficacy of Immunoglobulin was not constant, whereas G-CSF was effective at low doses and shortened the duration of infections.
Conclusion: Prolonged neutropenia in childhood must lead to look for phagocytosis by marrow macrophages in bone marrow smears, as a possible sign of autoimmunity. Growth factors may temporarily be used associated with antibiotics therapy in severe and prolonged infections.