Infections |
Viral | Infectious mononucleosis — Epstein-Barr virus (or other causes: cytomegalovirus, other herpes viruses, HIV, adenoviruses, toxoplasmosis) |
Cytomegalovirus (CMV) |
Mononucleosis syndrome (adenovirus type 12, herpes virus-6) |
HIV-1 (during early seroconversions associated with CMV) (chronic, associated with post-splenectomy state) |
HTLV-1 associated benign T cell lymphocytosis |
Mumps, varicella, influenza, hepatitis, rubella, roseola |
Infectious lymphocytosis (coxsackie virus B2, enteroviruses including poliovirus, others) |
Bacterial | Pertussis |
(Occasional) cat scratch fever, tuberculosis, brucellosis, syphilis |
Protozoal | Toxoplasmosis |
Parasitic | Babesiosis |
Rickettsial | (Occasional) scrub typhus |
Hypersensitivity | Drug-induced |
Serum sickness |
Stress | Post-trauma |
Post-splenectomy |
Cigarette smokers |
Autoimmune | Lymphocytosis of large granular lymphocytes |
Rheumatoid arthritis |
Malignant thymoma |
Endocrine | Hyperthyroidism |
Pre-malignant states | Monoclonal B cell lymphocytosis |