Chapter 78 : Neutropenia and Neutrophil Defects

Abstract:

Concern about the neutrophil status of a patient is usually raised on the basis of the frequency, severity, and distribution of a specific infectious agent(s) involved in one or more episodes that are, or are thought to be, infectious. The clinical presentations of patients with neutrophil disorders usually share a few common features: gingivitis, periodontal disease, and oral ulceration. Cutaneous infections with Staphylococcus aureus are often recurrent and can be severe. In neutrophil disorders characterized by inadequate inflammation (neutropenia, leukocyte adhesion deficiency [LAD], Chédiak-Higashi syndrome, and specific granule deficiency), infections can extend locally and subcutaneously with little reaction until marked destruction has taken place. Clinically relevant neutrophil abnormalities fall into several broad categories: neutropenia, abnormalities of neutrophil adherence and locomotion, abnormalities of neutrophil granule formation or content, and abnormalities of killing. With the widespread use of therapies which modulate the immune system either by design (e.g., steroids and monoclonal antibodies) or incidentally (e.g., cytotoxic chemotherapy), the most common causes of immunodeficiency are iatrogenic. The recognition, characterization, identification, and cloning of disease-related genes and, in some cases, genetic correction of immune defects are progressing rapidly. As specific and genetic treatments become available, making the correct diagnosis early takes on greater therapeutic importance (1).