Color Atlas of Hematology - Practical Microscopic and Clinical ...

66Abnormalities of the White Cell SeriesReactive LymphocytosisLymphatic cells show wide variability and transform easily. This is usuallyseen as enlarged nuclei, a moderately loose, coarse chromatin structure,and a marked widening of the basophilic cytoplasmic layer.Clinical findings, which include acute fever symptoms, enlarged lymphnodes, and sometimes exanthema, help to identify a lymphatic reactivestate. Unlike the case in acute leukemias, erythrocyte and thrombocytecounts are not significantly reduced. Although the granulocyte count isrelatively reduced, its absolute value (per microliter) rarely falls below thelower limit of normal values.Morphologically normal lymphocytes predominate in the blood analyses inthe following diseases:➤ Whooping cough (pertussis) with clear leukocytosis and total lymphocytecounts up to 20 000 and even 50 000/µl; occasionally, slightlyplasmacytoid differentiation.➤ Infectious lymphocytosis, a pediatric infectious disease with fever ofshort duration. Lymphocyte counts may increase to 50 000/µl.➤ Chickenpox, measles, and brucellosis, in which a less well-developedrelative lymphocytosis is found, and the counts remain within the normalrange.➤ Hyperthyroidism and Addison disease, which show relative lymphocytosis.➤ Constitutional relative lymphocytosis, which can reach up to 60% andoccurs without apparent reason (mostly in asthenic teenagers).➤ Absolute granulocytopenias with relative lymphocytosis (p. 86).➤ Chronic lymphocytic leukemia (CLL), which is always accompanied byabsolute and relative lymphocytosis, usually with high cell counts.Transformed, “stimulated” lymphocytes (“virocytes”) predominate in theCBC in the following diseases with reactive symptoms:➤ Lymphomatous toxoplasmosis does not usually involve significantleukocytosis. Slightly plasmacytoid cell forms are found.➤ In rubella infections the total leukocyte count is normal or low, and thelymphocytosis is only relatively developed. The cell morphology rangesfrom basophilic plasmacytoid cells to typical plasma cells.➤ In hepatitis the total leukocyte and lymphocyte counts are normal.However, the lymphocytes often clearly show plasmacytoid transformation.➤ The most extreme lymphocyte transformation is observed in mononucleosis(Epstein–Barr virus [EBV] or cytomegalovirus [CMV] infection)(p. 68).