Background: It is important to distinguish those with active Mycobacterium tuberculosis infection (ATB) from latent tuberculosis infection (LTBI) for monitoring and treating the disease. Monocytes play an important role and may undergo morphological changes against active TB infection. The aim of this study is to investigate the clinical usefulness of the monocyte morphometric parameters and monocyte chemoattractant protein-1 (MCP-1) to distinguish active tuberculosis (ATB) from latent tuberculosis infection (LTBI) and healthy controls (HC).
Methods: Peripheral blood was collected from 97 ATB patients, 113 LTBI patients, and 101 healthy controls. The monocyte morphometric parameters were obtained using a UniCel Coulter DxH800 system. MCP-1 level was determined by enzyme-linked immunosorbent assay method. Cutoff values were established based on receiver operator characteristic (ROC) curve analysis.
Results: Mean monocyte volume with its standard deviation, mean monocyte conductivity, and MCP-1 were significantly increased in ATB compared with LTBI and HC. ROC curve analyses showed that simultaneous measurements of mean monocyte volume with its standard deviation, mean monocyte conductivity and MCP-1 achieved good sensitivity and specificity (93.8% and 93.1%), which may be clinically useful.
Conclusions: The findings using monocyte morphometric parameters and MCP-1 to distinguish ATB from LTBI with high sensitivity and specificity may be a potential parameter for clinical.