Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (325 page)

   Hairy cell leukemia

   Follicular, mantle cell, and splenic marginal zone lymphomas in leukemic phase

   Large granular lymphocytic leukemia (see p. 404)

   Secondary (Reactive) Lymphocytosis

   Infections (e.g., pertussis, infectious mononucleosis [EBV], infectious lymphocytosis [especially in children], infectious hepatitis, CMV, mumps, German measles, chickenpox, toxoplasmosis, babesiosis, chronic TB, cat scratch disease)

   Noninfectious causes (e.g., hypersensitivity reactions, stress)

   Drugs: efalizumab (Raptiva)

LYMPHOCYTOPENIA

   Definition

Lymphocytes are <1,600/μL (or <18%) in adults and <3,000/μL in children

   Causes

   Corticosteroid therapy or Cushing syndrome; epinephrine injection

   Certain infections (e.g., acute and chronic retroviral infections, TB)

   Sarcoidosis

   Congenital immunoglobulin disorders

   Chemotherapy and radiation therapy