Several types of humoral immunity occurs. The secondary response begins immediately and results in long term recognition of specific antigens. Usually only one cell type is increased . If all cell types are increased, consider hemoconcentration .
Leukocytosis occurs only in acute infections .
In chronic infections, you may have high WBC but usually not above 10,000. ACTH causes leukocytosis in healthy person . ACTH masks leukocytosis in persons with severe infection . The differential can tell you what type of infection is present. Neutrophils Also called PMNs, segs or polys .