Neutropenia epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Daniel A. Gerber, M.D. [2]
Overview
Neutropenia is most commmon in at-risk patients undergoing cytotoxic chemotherapy or on other myelosuppressive medications, however a benign form of mild neutropenia is commonly identified in certain ethnicities (blacks, Yemenites, West Indians, Arab Jordanians) that does not impair the immune system.
Epidemiology and Demographics
Neutropenia is typically identified in at-risk patients undergoing cytotoxic chemotherapy or on other myelosuppressive medications. As noted above, some ethnicities have an unusually high prevalence of incidentally identified mild neutropenia, also termed constitutional or benign ethnic neutropenia (BEN). This is most common in blacks, Yemenites, West Indians, and Arab Jordanians and is suggested to be caused by a mutation in the Duffy antigen on red blood cells that helps to confer resistance to malaria. As the name suggests, these cases are typically mild and do not result in immunosuppression.
BEN is more often seen in blacks, Yemenites, West Indians, and Arab Jordanians with up to 4.5% prevalence in these populations. [1] In these individuals, a mutation in the Duffy antigen gene - a gene which encodes a red blood cell receptor used by malaria to enter these cells - both confers a protective effect against this parasite and, for unclear reasons, lowers the circulating neutrophil count. While quite common, the neutropenia is typically mild (ANC 1,000-1500 cells/microliter) and does not predispose to increased risk of infection or increased risk of febrile neutropenia in the setting of chemotherapy as these individuals have normal bone marrow neutrophil reserves.[2] [3] [4].
Immunodeficiencies are frequently associated with neutropenia (38% in Hyper IgM syndrome, 12% in CVID, and 7% in X-linked agammaglobulinemia) as are autoimmune disorders including up to 50% of patients with systemic lupus erythematosus, yet with lower overall prevalence. While rheumatoid arthritis infrequently presents with neutropenia, severe neutropenia can develop in the setting of large granular lymphocyte (LGL) leukemia or Felty's syndrome. [5]
References
- ↑ Hsieh MM, Everhart JE, Byrd-Holt DD, Tisdale JF, Rodgers GP (2007). "Prevalence of neutropenia in the U.S. population: age, sex, smoking status, and ethnic differences". Ann. Intern. Med. 146 (7): 486–92. PMID 17404350.
- ↑ Shoenfeld Y, Alkan ML, Asaly A, Carmeli Y, Katz M (1988). "Benign familial leukopenia and neutropenia in different ethnic groups". Eur J Haematol. 41 (3): 273–7. PMID 3181399.
- ↑ Shoenfeld Y, Ben-Tal O, Berliner S, Pinkhas J (1985). "The outcome of bacterial infection in subjects with benign familial leukopenia (BFL)". Biomed Pharmacother. 39 (1): 23–6. PMID 4027348.
- ↑ Hsieh MM, Tisdale JF, Rodgers GP, Young NS, Trimble EL, Little RF (2009). "Neutrophil count in African Americans: lowering the target cutoff to initiate or resume chemotherapy?". J Clin Oncol. 28 (10): 1633–7. PMID 20194862.
- ↑ Bucknall RC, Davis P, Bacon PA, Jones JV (2009). "Neutropenia in rheumatoid arthritis: studies on possible contributing factors". Ann Rheum Dis. 41 (3): 242–7. PMID 6979979.