علوم آزمایشگاهی دانشگاه علوم پزشکی تهران

Atypical Lymphocyte

Atypical, or reactive, lymphocytes are lymphocytes that, as a result of antigen stimulation, have become quite large, sometimes more than 30 µm in diameter. The cells vary greatly in size and shape. The nucleus is less clumped than that of the normal lymphocyte. The shape of the nucleus ranges from elliptic to cleft to folded. The chromatin patterns appear similar to those of a blast and faintly stained multiple nucleoli are visible. The cytoplasm may range from large, deeply basophilic, and abundant to unevenly stained and granular. Causes of reactive lymphocytosis may be: ß-Streptococcus, cytomegalovirus, drugs, Epstein-Barr virus (infectious mononucleosis), syphilis, toxoplasmosis, vaccination, and viral hepatitis.