The severity of infection can be estimated by a study of the cellular elements of the peripheral blood stream. The number of circulating leukocytes and the differential percentage of each type have until now been given the greatest attention. It is accepted that a leukopenia in a severe infection, which usually induces a marked leukocytosis (pneumonia), often forewarns of a poor or fatal prognosis. On the other hand, there are many systemic infections in which leukopenia is the rule but nevertheless the prognosis in general is good. Thus, the quantitative estimation of leukocytes certainly appears not to be the most important factor in the gaging of the prognosis.
The differential count varies with the different types of infection. In allergic infections, an eosinophilia may be present; in tuberculosis, a monocytosis is usually found; in very severe suppurative infections, myelocytes are noted; in subacute bacterial endocarditis (Streptococcus viridans), small numbers of
SUTRO CJ. CYTOPLASMIC CHANGES IN CIRCULATING LEUKOCYTES IN INFECTION. Arch Intern Med (Chic). 1933;51(5):747-753. doi:10.1001/archinte.1933.00150240106008