Ratio of monocytes to lymphocytes in peripheral blood in patients diagnosed with active tuberculosis

Abstract

Objective: The ratio of monocytes to lymphocytes in peripheral blood could reflect an individual's immunity to Mycobacterium tuberculosis. The objective of this study was to evaluate the relationship between ratio of monocytes to lymphocytes and clinical status of patients with active tuberculosis.

Methods: This was a retrospective review of data collected from the clinical database of The Fifth People's Hospital of Wuxi, Medical College of Jiangnan University. A total of 419 patients who had newly diagnosed active tuberculosis and 108 cases from 419 patients with tuberculosis therapy either near completion or completed were selected. Controls were 327 healthy donors.

Results: Median ratio of monocytes to lymphocytes was 0.36 (IQR, 0.22-0.54) in patients before treatment, and 0.16 (IQR, 0.12-0.20) in controls (p<0.001). Ratio of monocytes to lymphocytes <9% or >25% was significant predictors for active tuberculosis (OR=114.73, 95% CI, 39.80-330.71; OR=89.81, 95% CI, 53.18-151.68, respectively). After treatment, the median ratio of monocytes to lymphocytes recovered to be nearly normal. Compared to other patients, patients with extrapulmonary tuberculosis and of age >60 years were more likely to have extreme ratio of monocytes to lymphocytes (AOR=2.57, 95% CI, 1.08-6.09; AOR=4.36, 95% CI, 1.43-13.29, respectively).

Conclusions: Ratio of monocytes to lymphocytes <9% or >25% is predictive of active tuberculosis.

Keywords: Active tuberculosis; Lymphocytes; ML ratio; Monocytes.

Fig. 1

Patient selection criteria used in this study.

Fig. 2

Distribution of participants (patients and healthy donors) with ratio of monocytes to lymphocytes (ML ratio). (A) Monocytes and lymphocytes count are plotted on the x- and y-axes, respectively. ML ratio of healthy donors (blue circle) centralized mostly between the blue and green lines, ML ratio of patients (green circle) distributed mainly out of the lines. The dotted blue line denotes the 9th percentiles for ML ratio. The dotted green line denotes the 25th percentiles for ML ratios. (B) Median levels of ML ratio of patients of active tuberculosis and healthy donors. Each dot represents ML ratio for an individual patient or healthy donor. Bars represent medians. ML ratio of healthy donors gathered mainly in the area where the data from patients distributed rarely.

Fig. 3

Ratio of monocytes to lymphocytes (ML ratio) of patients, before treatment, after treatment and healthy donors. (A) ML ratio of patients with ML ratio greater than 25th percentile; (B) ML ratio of patients with ML ratio less than the 9th percentile; (C) ML ratio of patients with ML ratio between the 9th and 25th percentile. Data are presented with box plot reporting the median values and the interquartile range (***p < 0.001). Median ML ratio of patients changed to be close to healthy donors with anti-tuberculosis treatment.