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Inflammation
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Neutrophils protect the host against microbial invasion. In this host resistance, several steps are involved: production of neutrophils from bone marrow stem cells, maturation, release into circulation, sticking to vessel walls, mobility, migration into tissues, chemotaxis, phagocytosis degranulation, and digestion. Interference or abnormalities in any of these steps results in functional deficits. There are conditions where neutrophils are reduced in number or even absent. Individuals afflicted with agranulocytosis have greatly enhanced susceptibility to infection and sepsis. Application of excessive amounts of certain adrenal corticosteroids, cytotoxic drugs, or massive irradiation disturb the availability of neutrophils as well as their action on antibody formation. If these conditions suppress the production of neutrophils in the bone marrow, the circulating and tissue levels fall after the bone marrow pool is depleted. In a condition called cyclic neutropenia, the synthesis of neutrophils is intermittently inadequate due to a defect of the feedback regulatory mechanism that controls normal neutrophil production and function.87 Tumor promotors split centrosomes in polymorphonuclear neutrophils,405 and in breast cancer lysosomal enzymes of neutrophils show significant differences.42 Tetracyclin suppresses the production of migration inhibitory factors in humans, and thus the action of this antibiotic contributes to the bactericidal action of neutrophils.137
Host Defense I: Non-specific Immunity
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Congenital chronic neutropenia is the name given to a heterogeneous group of genetically-determined disorders characterized by a low rate of production of mature neutrophils. The most common complications are skin or respiratory tract infections with S. aureus, or overgrowth or dissemination of normal enteric flora. The frequency and severity of these infections correlates with the degree of neutropenia. In cyclic neutropenia, as its name implies, the number of circulating neutrophils fluctuates. Oral or skin infections may occur during episodes of neutropenia. Several rare genetic disorders are characterized by low or absent neutrophils. Examples include infantile genetic agranulocytosis (Kostmann syndrome); and Schwachman syndrome, in which neutropenia is associated with pancreatic insufficiency.
Mitochondrial Dysfunction and Barth Syndrome
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Arianna F. Anzmann, Steven M. Claypool, Hilary Vernon
Neutropenia is also seen in most affected individuals and can present as severe chronic neutropenia, cyclic neutropenia, or intermittent/non-cyclical neutropenia. Low neutrophil counts put affected individuals at risk for severe bacterial infections, ranging from mouth ulcers and gingival inflammation, to sepsis and multi-organ system failure7,11.
Cyclic manner of neutropenia in a patient with HAX-1 mutation
Published in Pediatric Hematology and Oncology, 2018
Funda Erol Cipe, Mehmet Halil Celiksoy, Biray Erturk, Çiğdem Aydogmus
Cyclic neutropenia is a type of congenital neutropenia in which the blood neutrophil count undergoes regular decreases from normal to very low at 18–21-day intervals [5]. Cyclic neutropenia was first described in 1947 [6], and the causative mutation in ELA2 was identified in 1999 [7]. Cyclic neutropenia causes recurrent and sometimes life-threatening infections [5]; e.g., periodontitis, aphthous stomatitis, and typhlitis. The neutrophil count can decrease to below 500/μL; numbers of monocytes, platelets, lymphocytes, and reticulocytes cycle at the same frequency [8]. Cyclic neutropenia patients show accelerated apoptosis of bone marrow progenitor cells at all stages in the cyclic neutropenia cycle. G-CSF therapy increases the survival of bone marrow progenitor cells and the neutrophil count [7]. Cyclic neutropenia is associated with mutations in the ELANE, AP3B1, and Hermansky–Pudlak syndrome type 2 genes [8, 9]. ELANE mutations are the most common causes of severe congenital neutropenia as well as sporadic and autosomal-dominant cyclic neutropenia [9]. Neutrophil elastase produced by neutrophils inhibits production of further neutrophils [5]. Our patient did not have an ELANE mutation.