The morphological changes of monocytes in peripheral blood as a potential indicator for predicting active pulmonary tuberculosis.

BACKGROUND: Monocytes play a crucial role in immune response against Mycobacterium tuberculosis infection. The purpose of this current study was to investigate the morphology present on monocytes in peripheral blood from patients with active pulmonary tuberculosis (APTB) and the laboratory performance of the changes for discriminating cases from normal healthy subjects (NHS).

METHOD: A total of 71 peripheral blood samples from patients with APTB, and 65 samples from NHS were analyzed. The mean monocyte volume with its distribution width and mean monocyte conductivity as well as monocyte light scatter were detected by VCS technology used on the LH750 hematology analyzer. Correlations of these changes with the serum cytokine level in the immune alterations were further evaluated. The Receiver operating characteristic curve (ROC) analysis was used to highlight the clinical implication.

RESULTS: In APTB patients, the mean monocyte volume showed significant difference associated with an evident elevation in the mean monocyte volume distribution width compared to those in NHS. Furthermore, the mean monocyte volume had positive relationship with the serum level of interleukine-1β response to M. tuberculosis infection. Simultaneous measurement of the mean monocyte volume and its distribution width was able to distinguish active infection with an excellent sensitivity of 84.5% and specificity of 90.5% comparable to those obtained from pro-inflammatory cytokine interleukine-6 identifying APTB with great accuracy.

CONCLUSION: The morphological changes of monocytes particular increased mean volume may be a potential indicator to predict active tuberculosis infection.