reactive lymphocyte


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Related to reactive lymphocyte: plasma cell

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.

reactive lymphocyte

A lymphocyte that has become enlarged as a result of stimulation by antigens. Such a lymphocyte can be over 30 µm in diameter and of varying sizes and shapes.
See also: lymphocyte
References in periodicals archive ?
3] (neutrophils 55%, lymphocytes 35%, monocytes 7%, reactive lymphocytes and Downey cells), hemoglobin 12 g/dL, hematocrit 38%, and normal platelet count.
Abnormal cells, band forms, and reactive lymphocytes are easily detected and numbers estimated when the slide is scanned by an expert.
The development of the immune system, including the development of the repertoire of reactive lymphocytes that will exist in postnatal life, begins prenatally.

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