Overview of Leukopenias

By Mary Territo, MD, University of California, Los Angeles

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Leukopenias
Overview of Leukopenias
Lymphocytopenia
Monocytopenia
Neutropenia

Leukopenia is a reduction in the circulating WBC count to < 4000/μL. It is usually characterized by a reduced number of circulating neutrophils, although a reduced number of lymphocytes, monocytes, eosinophils, or basophils may also contribute. Thus, immune function is generally decreased.

Neutropenia is a reduction in blood neutrophil count to < 1500/μL in whites and <1200/μL in blacks. It is sometimes accompanied by monocytopenia and lymphocytopenia, which cause additional immune deficits.

Lymphocytopenia, in which the total number of lymphocytes is < 1000/μL in adults, is not always recognized as a decrease in the total WBC count because lymphocytes account for only 20 to 40% of the total WBC count. The consequence of the lymphopenia can depend on the lymphocyte subpopulation(s) that are decreased.

Monocytopenia is a reduction in blood monocyte count to < 500/μL. Monocytes migrate into the tissues where they become macrophages, with characteristics depending on their tissue localization.

Last full review/revision November 2016 by Mary Territo, MD