Automated Cytochemical Differential Leucocyte Count in Patients Hospitalized with Acute Bacterial Infections

Abstract

Absolute blood levels of various leucocyte types were measured by an automated cytochemical differential count (Hemalog D/90) in 84 adult patients hospitalised with an acute bacterial infection. The neutrophil granulocyte levels varied widely in all patient categories ranging from a normal value to a high count. Neutrophilic granulocytosis defined by a count exceeding 6.0×10⁹/l was detected in 47 patients (56%). An increased level of neutrophils with a high myeloperoxidase activity (Hpx cells) representing leucocytes recruited from the bone marrow was found in 51 patients (61%). Monocytosis was found in 25 (30%) and lymphocytopenia in 23 patients (27%). A high number of large unstained cells indicating an increase in atypical lymphocytes was detected in only 3 persons. Entirely normal cytochemical parameters were recorded in 13 patients (15%). The relationship between various leucocyte types was investigated in 26 patients with erysipelas. A negative association (r=–0.59) was observed between the neutrophil and the monocyte count. There was no correlation between the neutrophil and the lymphocyte count, nor between the levels of monocytes and lymphocytes. A positive correlation (r=0.76) was established between the neutrophil count and the level of Hpx cells indicating that recruitment of immature cells from the bone marrow reserve pool is a feature of patients with erysipelas. The high precision and reproducibility of the cytochemical differential count indicate that the variability noted in the disease categories studied is a biological one, being the result of the complex interaction of invading microorganisms with the host defence system.