To analyze the dynatic changes of monocytes and related cytokines in peripheral blood of patients with active pulmonary tuberculosis (APTB) and in peripheral blood of healthy people retrospectively, so as to explore the correlation between the diseases and the cells, the cytokines, and investigate their clinical application value.

Peripheral blood specimens from 72 patients with APTB and 79 healthy controls were measured by using Myrtle BC-6900 automatic hematology analyzer. Percentage of monocyte (MO%) and monocyte counts (MO#) were recored by the analyzer. Serum levels of Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) were measured in the two groups. Then comparative analysis of the inter-group index was carried out, and the correlation between monocyte parameters and cytokine concentration was analyzed. Operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of each index in the diagnosis of APTB.

The peripheral blood Mo% and Mo# in the case group were significantly higher than those in the normal control group (t=5.135, P<0.001 and t=5.510, P<0.001). The serum IL-1β、IL-6 and TNF-α concentrations in the patients with APTB were significantly higher than those in healthy controls and the different was statistically signtficant (U=405.000, P<0.001, U=543.500, P<0.001, and U=563.000, P<0.001). There was a weak negative correlation between Mo# and IL-6 (r=-0.247、P<0.05). A comparative analysis of diagnostic performance between projects showed that AUCs of IL-1β, IL-6 and TNF-α (AUC=0.891, 0.918 and 0.887 respectively) were higher than that of MO% and MO# (AUC=0.758 and 0.735, respectively).When the critical value of IL-1β was 9.0175 ng/l, the sensitivity and specificity of diagnosing APTB were 83.3% and 81.2% respectively; when the critical value of IL-6 was 3.835 ng/l, the sensitivity and specificity of the diagnosing APTB were 86.1% and 84.4% respectively; when the critical value of TNF-α was 138.545 ng/l, the sensitivity and specificity of diagnosing APTB were 80.6% and 81.2%, which were superior to MO% (65.3% vs. 62.0%) and MO# (70.8% vs. 64.6%). In addition, the area under the curve obtained by simultaneous measurement of IL-1β, IL-6 and TNF-α was as high as 0.987, and the sensitivity and specificity of diagnosing APTB were 95.8% and 92.8%, respectively.

During APTB, the peripheral blood mononuclear cells (MO) may migrate to the alveoli and then evolve into macrophages (M?) and the activated M? may produce a series of cytokines, which may have a certain impact on the number of monocytes in the circulating pool and can be used as an ideal marker to distinguish APTB from the normal individuals.