possessed lung adenocarcinoma. clinical significance micrograph showing several neutrophils during an acute inflammation low neutrophil counts are termed neutropenia. this can be congenital (developed at or before birth) or it can develop later, as in the case of aplastic anemia or some kinds of leukemia. it can also be a side-effect of medication, most prominently chemotherapy. neutropenia makes an individual highly susceptible to infections. it can also be the result of colonization by intracellular neutrophilic parasites. in alpha 1-antitrypsin deficiency, the important neutrophil elastase is not adequately inhibited by alpha 1-antitrypsin, leading to excessive tissue damage in the presence of inflammation – the most prominent one being emphysema. negative effects of elastase have also been shown in cases when the neutrophils are excessively activated (in otherwise healthy individuals) and release the enzyme in extracellular space. unregulated activity of neutrophil elastase can lead to disruption of pulmonary barrier showing symptoms corresponding with acute lung injury. the enzyme also influences activity of macrophages by cleaving their toll-like receptors (tlrs) and downregulating cytokine expression by inhibiting nuclear translocation of nf-κb. in familial mediterranean fever (fmf), a mutation in the pyrin (or marenostrin) gene, which is expressed mainly in neutrophil granulocytes, leads to a constitutively active acute-phase response and causes attacks of fever, arthralgia, peritonitis, and – eventually – amyloidosis. hyperglycemia can lead to neutrophil dysfunction. dysfunction in the neutrophil biochemical pathway myeloperoxidase as well as reduced degranulation are associated with hyperglycemia. the absolute neutrophil count (anc) is also used in diagnosis and prognosis. anc is the gold standard for determining severity of neutropenia, and thus neutropenic fever. any anc < 1500 cells / mm3 is considered neutropenia, but <500 cells / mm3 is considered severe. there is also new research tying anc to myocardial infarction as an aid in early diagnosis. neutrophils promote ventricular tachycardia in acute myocardial infarction. in autopsy, the presence of neutrophils in the heart or brain is one of the first signs of infarction, and is useful in the timing and diagnosis of myocardial infarction and stroke. neutrophils are seen in a myocardial infarction at approximately 12–24 hours, as seen in this micrograph. in stroke, they are beginning to infiltrate the infarcted brain after 6 to 8 hours. neutrophil antigens there are five (hna 1–5) sets of neutrophil antigens recognized. the three hna-1 antigens (a-c) are located on the low affinity fc-γ receptor iiib (fcgr3b :cd16b) the single known hna-2a antigen is located on cd177. the hna-3 antigen system has two antigens (3a and 3b) which are located on the seventh exon of the clt2 gene (slc44a2). the hna-4 and hna-5 antigen systems each have two known antigens (a and b) and are located in the β2 integrin. hna-4 is located on the αm chain (cd11b) and hna-5 is located on the αl integrin unit (cd11a). subpopulations activity of neutrophil-killer and neutrophil-cager in nbt test two functionally unequal subpopulations of neutrophils were identified on the basis of different levels of their reactive oxygen metabolite generation, membrane permeability, activity of enzyme system, and ability to be inactivated. the cells of one subpopulation with high membrane permeability (neutrophil-killers) intensively generate reactive oxygen metabolites and are inactivated in consequence of interaction with the substrate, whereas cells of another subpopulation (neutrophil-cagers) produce reactive oxygen species less intensively, don't adhere to substrate and preserve their activity. additional studies have shown that lung tumors can be infiltrated by various populations of neutrophils. video neutrophils display highly directional amoeboid motility in infected footpad and phalanges. intravital imaging was performed in the footpad path of lysm-egfp mice 20 minutes after infection with listeria monocytogenes. additional images blood cell lineage more complete lineages