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neutrophil or polymorphonuclear leukocyte (PMN, poly)

Function: - steps in neutrophil function: a) response to chemotactic factors b) adhesion to vascular endothelium c) passage through tight junctions between endothelial cells d) adherence, phagocytosis & lysis of infectious agent Physiology: - for each neutrophil in peripheral blood, about 16 myeloid precursors are present in the bone marrow - about 5 mitotic divisions from myeloblast to neutrophil, with 3 at the myelocyte stage takes about 14 days - the last 6-7 days of development are spent in the maturation & storage pool - neutrophils enter the peripheral blood & distribute between a circulating pool (measured in the leukocyte count (WBC count) & neutrophil count & a marginated pool along vessel walls or in capillary beds (margination or pavementing of neutrophils) - marginated neutrophils can be rapidly mobilized - neutrophils enter tissues randomly in the absence of chemotactic signals & leave the body in a few days via secretions from bronchi, saliva, GI tract, or urine, or are destroyed by the reticuloendothelial system [3] - 1/2 life of neutrophils in peripheral blood is ~ 5 days [5] - neutrophils move in a zigzag fashion, but in a straight line in response to neutrophil chemotactic factor(s) - neutrophils are the 1st cells to arrive at sites of bacterial infections & fungal infections - neutrophils are phagocytes, sequestering pathogens in phagocytic vacuoles - degranulation of cytoplasmic granules into the vacuoles with activation & release of myleoperoxidase & other enzymes into the vacuoles provides bactericidal activity Biochemistry: - neutrophils express chemokine receptor CXCR1 & CXCR2 responsible for the migration of neutrophils in response to chemokines - neutrophils also have receptors for the Fc part of IgG (Fc gamma receptor) & for complement C3 - surface markers: -> CD10, CD11b, CD13, CD14, CD15, CD16, CD33 Pathology: 1) contents of neutrophil granules activated & released outside of phagocytic vacuoles can result in inflammation, tissue injury, & tissue necrosis 2) disorders associated with neutrophil function: a) disorders resulting in neutropenia - chemotherapy - radiation therapy - adverse drug reaction - risk of infection increased markedly when the absolute neutrophil count drops below 500-1000/uL (see neutropenia) b) abnormal neutrophil phagocytosis & bactericidal activity - alcoholism & cirrhosis - type-2 diabetes mellitus - prolonged corticosteroid use* - absence of antibodies or complement components required to opsonize micro-organisms c) disorders of neutrophil chemotaxis * most common cause of disordered neutrophil phagocytosis Laboratory: 1) normal neutrophil count is 3000-6000/uL, & 50-70% of circulating WBC 2) assessment of neutrophil function a) chemotaxis b) bactericidal activity c) nitroblue tetrazolium dye reduction test for abnormalities in neutrophil oxidative metabolism 3) labs with Loincs - neutrophils in specimen - neutrophils in bronchial specimen - neutrophils in nose - neutrophils in body fluid - neutrophil count (neutrophils in blood) - neutrophils.agranular in blood - neutrophils.dysplastic in blood - neutrophils.hypogranulated in blood - neutrophils.vacuolated in blood - neutrophils in blood from fetus - neutrophils in CSF - neutrophils in dialysis fluid - neutrophils in pericardial fluid - neutrophils in peritoneal fluid - neutrophils in pleural fluid - neutrophils in prostatic fluid - neutrophils in semen - neutrophils in sputum - neutrophils in stool - neutrophils in synovial fluid - neutrophils in urine - neutrophils in vitreous fluid - neutrophil oxidative burst in blood 4) see ARUP consult [4]

Related

CD10 (neprilysin, neutral endopeptidase, enkephalinase, common acute lymphoblastic leukemia antigen, CALLA, atriopeptidase, MME, EPN) CD11b; integrin alpha-M; cell surface glycoprotein MAC-1 subunit alpha; CR-3 alpha chain; leukocyte adhesion receptor MO1; neutrophil adherence receptor; CD11 antigen-like family member B; (ITGAM, CD11B, CR3A) CD13; aminopeptidase-N; aminopeptidase-M; gp150; microsomal aminopeptidase; alanine aminopeptidase (ANPEP, PEPN) CD14; monocyte differentiation antigen CD14; myeloid cell-specific leucine-rich glycoprotein CD15, Lewis X or X-hapten CD16, Fc gamma receptor III or Fc gamma receptor (low affinity) CD33; myeloid cell surface antigen CD33; sialic acid-binding Ig-like lectin 3; siglec-3; gp67 (SIGLEC3) granulocyte transfusion neutropenia neutrophil count Pelger-Huet anomaly phagocytic disorder

Specific

LE cell neutrophilic band segmented neutrophil

General

granulocyte phagocyte

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
  2. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 352
  3. Henry's Clinical Diagnosis & Management by Laboratory Methods, 21st edition, McPherson RA & Pincus MR (es), W.B. Saunders Co., Philadelphia, PA. 2007, page 495
  4. ARUP Consult: Neutrophil Disorders deprecated reference
  5. Pillay J Response: The in vivo half-life of human neutrophils. Blood. 2011 117(22) http://www.bloodjournal.org/content/117/22/6053?sso-checked=true