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 ?
Atypical lymphocyte morphology, including pseudopods, split nuclei, and cytoplasmic granules, was observed in 5% of the birds.
33%) were triggered by atypical lymphocyte flags, and 9 of 12 (75%) were triggered by blast flags (abnormal lymphocytes/ lymphoblast flags).
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 "blast" flag appeared in 33 cases but did not imply a difference in mean for atypical lymphocyte count (5.
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.
This observation corresponds to our previous experiences with other hematology analyzers and might best be explained by the rather broad definition of an atypical lymphocyte.
In addition, a control group that consisted of a selection of 50 patients from the 1689 original patients who were heterophile antibody negative but who had a normal lymphocyte count and generated no atypical lymphocyte flag were also tested for EBV IgM antibodies.
The combination of a patient having greater than 50% lymphocytes and greater than 10% atypical lymphocytes is also useful.
Listed occasionally are plasma cells, band cells, atypical lymphocytes, and abnormal reticulocyte count.
Lymphoma was not considered in the differential diagnosis because of the absence of numerous atypical lymphocytes.
Drug reaction with eosinophilia and systemic symptom (DRESS) syndrome is a severe adverse drug-induced reaction that usually presents clinically as an extensive skin rash, accompanied by fever, lymphadenopathy, hepatitis, hematologic abnormalities with eosinophilia and atypical lymphocytes, and may involve multiple organs.

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