Disorders of neutrophil function

Abstract

The major role of neutrophil leukocytes is to ingest, kill, and digest invading microorganisms, particularly bacteria and fungi. Failure to fulfil this role leads to recurrent, severe, or chronic infections, often with a family history of similar problems. Neutrophil activity is subdivided conveniently into stages and qualitative defects classified according to the functional step affected. Neutrophils are produced in the bone marrow from white-cell precursors that are in turn derived from pluripotential stem cells. Initial stages, from stem cells through to myeloblasts, promyelocytes, and myelocytes, involve three to five cell divisions over about 7 days. The neutrophil myeloid precursors then mature through non-dividing stages of metamyelocytes and segmented forms over the next week to form a storage pool of matured cells. This chapter discusses the defects in neutrophil function. Defects in neutrophil function may be quantitative or qualitative. A critical number of circulating, functioning neutrophils is required for adequate defense. The study of patients with recurrent infections has led to the discovery of neutrophil dysfunction in a variety of diseases. In many instances, different etiological factors may have the same result.