Idiopathic, immune, infectious, and idiosyncratic neutropenias

In idiopathic and immune neutropenias the susceptibility to infectious agents is highly variable, but the reason why some patients exhibit no undue susceptibility whereas others contract life-threatening infections is poorly understood. An important factor is the efficacy of delivery of neutrophils to the tissues. Recent investigations of the mechanisms for mild to moderate chronic neutropenias have shown the significance of interactions between myelopoiesis and the immune system, as for example, in relation to immunoglobulin aberrations and the cytokine network. Antibody-mediated neutropenias (alloimmune, autoimmune) are now well-characterized diseases. If infections occur, apart from antibiotics, granulocyte colony-stimulating factor (G-CSF) is the treatment of choice, while intravenous or monoclonal immunoglobulins and cyclosporine are reserved for refractory cases.