Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ LYMPHOCYTOSIS ++ Definition ++ Adults: absolute lymphocyte count exceeds 4.0 × 109/L (see Chap. 1). Normal lymphocyte count in childhood is higher than adults (mean ~6.0 × 109/L) until about 3 years of age (see Chap. 1). Table 50–1 lists conditions associated with lymphocytosis. Examine blood film to determine if there is abnormal prevalence of: — Reactive lymphocytes, associated with infectious mononucleosis (see Chap. 53). — Large granular lymphocytes, associated with large granular lymphocyte leukemia (see Chap. 58). — Small lymphocytes and smudge cells, associated with chronic lymphocytic leukemia (CLL) (see Chap. 56). — Small cleaved lymphocytes, associated with low- or intermediate-grade lymphomas (see Chap. 62). — Blasts, associated with acute lymphocytic leukemia (see Chap. 55). Several key tests permit discrimination between polyclonal and monoclonal disorders. Flow cytometric immunophenotyping of cell surface markers (CD), serum protein electropheresis and immunofixation for monoclonal immunoglobulins, studies of T-cell–receptor gene rearrangement, or clonal cytogenetic findings can distinguish monoclonal lymphocytosis (B or T lymphocytic leukemia or lymphoma) from polyclonal (reactive) lymphocytosis. ++Table Graphic Jump LocationTABLE 50–1CAUSES OF LYMPHOCYTOSISView Table|Favorite Table|Download (.pdf) TABLE 50–1 CAUSES OF LYMPHOCYTOSIS Primary lymphocytosis Lymphocytic malignancies Acute lymphocytic leukemia (Chap. 55) Chronic lymphocytic leukemia and related disorders (Chap. 56) Prolymphocytic leukemia (Chap. 55) Hairy cell leukemia (Chap. 57) Adult T-cell leukemia (Chaps. 55 and 67) Leukemic phase of B-cell lymphomas (Chaps. 61, 62) Large granular lymphocytic leukemia (Chaps. 58, 67) Natural killer (NK) cell leukemia (Chap. 67) CD8+ T-cell large granular lymphocytic leukemia (Chap. 67) CD4+ T-cell large granular lymphocytic leukemia (Chap. 67) ᵞ/δ T-cell large granular lymphocytic leukemia (Chap. 67) Monoclonal B-cell lymphocytosis (Chap. 56) Persistent polyclonal B cell lymphocytosis Reactive lymphocytosis Mononucleosis syndromes (Chap. 53) Epstein-Barr virus Cytomegalovirus Human immunodeficiency virus Herpes simplex virus type II Rubella virus Toxoplasma gondii Adenovirus Infectious hepatitis virus Dengue fever virus Human herpes virus type 6 (HHV-6) Human herpes virus type 8 (HHV-8) Varicella zoster virus Bordetella pertussis NK cell lymphocytosis (see Chap. 58) Stress lymphocytosis (acute) Cardiovascular collapse Acute cardiac failure Myocardial infarction Staphylococcal toxic shock syndrome Drug-induced Major surgery Sickle cell crisis Status epilepticus Trauma Hypersensitivity reactions Insect bite Drugs Persistent lymphocytosis (subacute or chronic) Cancer Cigarette smoking Hyposplenism Chronic infection Leishmaniasis Leprosy Strongyloidiasis Thymoma Source: Williams Hematology, 8th ed, Table 81–1, p. 1142. ++ Primary Clonal Lymphocytosis ++ Neoplastic (monoclonal) proliferation of B cells, T cells, or natural killer (NK) cells. Monoclonal B-cell lymphocytosis (see Chap. 56). — No associated clinical manifestations. — Some patients may develop CLL or another type of progressive lymphoproliferative disease (see Chap. 56). Chronic natural killer (NK) cell lymphocytosis (see Chap. 58). — CD3−CD16+CD56+ lymphocytes — Approximately 60 percent ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. What is MyAccess? Create a FREE MyAccess profile to: Use this site remotely Bookmark your favorite content Track your self-assessment progress and more!