atypical lymphocyte

atypical lymphocyte

An enlarged dysmorphic lymphocyte characterised by an often irregular monocyte-like nucleus that may stretch the length of the cell, with chromatin strands that parallel the length of the nucleus; nucleoli and azurophilic granules may be present. Atypical lymphocytes are seen in various non-neoplastic conditions, classically in infectious mononucleosis (<20% of circulating WBCs are atypical), toxoplasmosis, CMV infection and viral hepatitis.

ALs were formerly (and arbitrarily) grouped into three types, now of historic interest:
• Type I—Monocyoid or prolymphocytic kidney-shaped or lobulated nuclei, with densely homogeneous hypergranular chromatin, more similar to mature lymphocytes than plasma cells; cytoplasm is bubbly, eccentric and basophilic.
• Type II—Cytoplasmic radiations from the nucleus (“ballerina skirt” cells); cells have 1+ nucleoli; chromatin is less dense and cytoplasm is less foamy than type I, contains some azurophilic granules, is basophilic, and “scallops” around RBCs.
• Type III—Nuclei are coarse, span the cell’s breadth, have clumped red-to-purple chromatin with 1–4 nucleoli; the cytoplasm is abundant, basophilic, and “scallops” around adjacent RBCs. ALs have abundant cytoplasm, with basophilic condensations where they abut RBCs; mitochondria are large, numerous and scattered throughout the cytoplasm.

atypical lymphocyte

Downey cell Hematology An enlarged dysmorphic lymphocyte characterized by an often irregular monocyte-like nucleus which may stretch the length of the cell, with chromatin strands that parallel the length of the nucleus; nucleoli and azurophilic granules may be present; ALs are seen in various non-neoplastic conditions, classically in infectious mononucleosis, toxoplasmosis, CMV infection, and viral hepatitis. See Azurophilic granule.
References in periodicals archive ?
Microscopically medium-sized monomorphic atypical lymphocyte infiltration with dark nucleus and narrow cytoplasm was seen in the layers of mucosa, submucosa, muscular wall, and serosa of the duodenum (Figure 1).
A punch biopsy specimen was obtained from his eyebrow lesion, which rendered diffuse infiltration of atypical lymphocyte cells with some convoluted nuclei and scant cytoplasm admixed with lymphocytes, histiocytes, and mast cells compatible with the nodular stage of MF.
Preoperative liver, renal function, and white blood cell (WBC) count were within normal limits without evidence of blast or atypical lymphocyte. Contrast-enhanced CT showed hypodense lesions and fluid collection in the medial posterior compartment of the left lower leg (Figure 1).
Atypical lymphocyte morphology, including pseudopods, split nuclei, and cytoplasmic granules, was observed in 5% of the birds.
(4.) Wood TA, Frenkel ER The atypical lymphocyte. Am J Med.
The evaluation included a leukocyte count, with results (7.8 x [10.sup.3] cells/[mm.sup.3]) within the reference values and with a differential count of 26% bands, 59% neutrophils, 8% lymphocytes, 6% monocytes, and 1% atypical lymphocyte; blood culture results were negative.
of basophils, >500 NA /[micro]L Basophil, % NA >4 Reticulocyte Absolute reticulocyte, >0.100 NA x [10.sup.3]/[micro]L Suspect flags Nucleated red Flag Flag blood cell Blast Flag Flag Atypical lymphocyte Flag Flag RBC fragment Flag NA Dimorphic RBC Flag NA Lyse resistant Flag NA Immature granulocyte Flag NA Left shift Flag NA PLT clump Flag NA Platelet (except Flag NA PLT clump) Suspect flag (except Flag NA ImmG/band in adult) Suspect flag (child) Flag NA Abbreviations: CBC, complete blood count; HGB, hemoglobin; ImmG, immature granulocyte; MCV, mean corpuscular volume; NA, not available; PLT, platelet; RDW, red cell distribution width; WBC, white blood cell; RBC, red blood cell.
% RBC morphology 22 51.2 23 53.5 17 58.6 Platelet morphology 11 25.6 12 27.9 9 31.0 Metamyelocyte, myelocyte, 9 20.9 7 16.3 2 6.9 promyelocyte Atypical lymphocyte 2 4.7 1 2.3 1 3.4 WBC morphology 1 2.3 2 4.7 0 0.0 NRBC 0 0.0 1 2.3 0 0.0 Blast 0 0.0 0 0.0 0 0.0 Total 43 100.0 43 100.0 29 100.0 Abbreviations: NRBC, nucleated red blood cell; RBC, red blood cell; WBC, white blood cell.
(24) A second proposed mechanism for the aggregation of IVLBCL cells to the lumina of small vessels is the aberrant expression of G protein-coupled receptor 9 (CXCR3) among atypical lymphocytes, and aberrant expression of its ligand, chemokine ligand 9 (CXCL9), by the endothelial cells of small vessels, which may mediate atypical lymphocyte migration to these areas.
The abnormality-specific PPV of all but the atypical lymphocyte flag was improved, whereas all overall PPVs were improved by optimization.
Proportion positive for Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, Toxoplasma, and human immunodeficiency virus types 1 and 2 in heterophile-negative patients with an absolute lymphocytosis or an instrument-generated atypical lymphocyte flag.
specifically: for whites, it should be possible to label atypical lymphocytes, shoots, leucopenia, leukocytosis, lymphopenia, lymphocytosis, neutropaenia, neutropenia, eosinophilia, monocytes, basophilia, and to produce parameters for the degraded forms of the leukocyte type.

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