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Published on: January 31, 2018
[Early diagnostic value of circulating microparticles in super-elderly patients with infection]
Yaping Yuan1,2, Tingting Liu1,2, Jionghe Wu1,2
1Chinese PLA Medical School, Beijing 100853, China.
Objective:
To investigate the level and changing trend of microparticles (MPs) in super-elderly infected patients, and explore its early warning effect on infection.
Methods:
The infected patients ≥ 85 years old admitted to the Second Medical Center of Chinese PLA General Hospital from December 2018 to March 2019 were selected as the observation group, and the healthy volunteers ≥ 85 years old in the same period were selected as the control group. Venous blood samples were collected at the 2nd hour, the 2nd day and the 7th day after fever, and the inflammatory markers such as white blood cell count (WBC), neutrophil percentage (NEUT), C-reactive protein (CRP) and procalcitonin (PCT) were measured. The levels of MPs were determined by flow cytometry. Annexin V labeled CD11b positive MPs (Annexin V+/CD11b+ MPs) represented leukocyte microparticles (LMPs), and Annexin V labeled CD66b positive MPs (Annexin V+/CD66b+ MPs) represented neutrophil microparticle (NMPs). The differences of each index at different time points between the two groups were compared, and the predictive value of each index to the infection of elderly patients was analyzed by receiver operating characteristic (ROC) curve.
Results:
A total of 38 subjects were enrolled, including 28 cases in the observation group and 10 cases in the control group. The levels of LMPs and NMPs in the observation group increased to the peak at the 2nd hour after fever, and were significantly higher than those in the control group [LMPs (cells/μL): 55.0 (28.8, 197.2) vs. 19.0 (13.5, 28.3), NMPs (cells/μL): 226.5 (123.3, 516.5) vs. 26.5 (22.0, 48.8), both P < 0.01]. With the control of the disease, LMPs and NMPs decreased gradually. The NMPs on the 2nd day was significantly lower than that at the 2nd hour of fever [cells/μL: 106.0 (40.0, 309.0) vs. 226.5 (123.3, 516.5), P < 0.05], and the LMPs and NMPs on the 7th day were significantly lower than those on the 2nd day [LMPs (cells/μL): 17.0 (12.5, 43.8) vs. 42.0 (13.0, 117.0), NMPs (cells/μL): 30.0 (15.8, 62.0) vs. 106.0 (40.0, 309.0), both P < 0.05]. There was no significant difference in the levels of LMPs and NMPs between the two groups on the 7th day. Among the inflammatory markers, the NEUT in the observation group was significantly higher than that in the control group at the 2nd hour of fever (0.70±0.09 vs. 0.59±0.04, P < 0.01), but there was no significant difference in WBC, CRP and PCT between the two groups. On the 2nd day, the inflammatory markers in the observation group reached the peak and were significantly higher than those in the control group [WBC (×109/L): 9.33±2.44 vs. 6.37±1.28, NEUT: 0.78±0.08 vs. 0.57±0.04, CRP (mg/L): 5.67±2.99 vs. 0.33±0.18, PCT (μg/L): 0.80±0.67 vs. 0.07±0.03, all P < 0.01]. On the 7th day, the inflammatory markers in the observation group decreased significantly, and there was no significant difference between the observation group and the control group. ROC curve analysis showed that the area under ROC curve (AUC) and 95% confidence interval (95%CI) of LMPs and NMPs on the day of fever were higher than those of WBC, NEUT, CRP and PCT [0.888 (0.763-1.000), 0.973 (0.931-1.000) vs. 0.679 (0.346-0.811), 0.829 (0.700-0.958), 0.607 (0.404-0.811), 0.554 (0.358-0.749)].
Conclusions:
LMPs and NMPs are significantly increased in the early stage of fever, which can predict the incidence of infection in the super-elderly patients.
Insights
Leukocyte microparticles (LMPs) and neutrophil microparticles (NMPs) are elevated in super-elderly patients with infections, serving as early indicators. Their levels decrease as the infection is treated, aiding in monitoring recovery.
Area of Science:
- Gerontology
- Immunology
- Biomarkers
Background:
- Super-elderly individuals (≥85 years) are susceptible to infections.
- Early detection of infection in this population is crucial for timely intervention.
- Traditional inflammatory markers may not always be sufficient for early infection detection in the super-elderly.
Purpose of the Study:
- To investigate the levels and trends of microparticles (MPs) in infected super-elderly patients.
- To explore the early warning potential of MPs in predicting infection in this demographic.
- To compare the efficacy of MPs as biomarkers against traditional inflammatory markers.
Main Methods:
- A case-control study involving infected super-elderly patients and healthy controls.
- Blood samples collected at 2 hours, 2 days, and 7 days post-fever onset.
- Flow cytometry used to quantify leukocyte microparticles (LMPs) and neutrophil microparticles (NMPs).
- Levels of white blood cell count (WBC), neutrophil percentage (NEUT), C-reactive protein (CRP), and procalcitonin (PCT) were measured.
- Receiver operating characteristic (ROC) curve analysis was employed to assess predictive values.
Main Results:
- LMPs and NMPs peaked at 2 hours post-fever in infected patients, significantly higher than controls (P < 0.01).
- Levels of LMPs and NMPs decreased over time with treatment, normalizing by day 7.
- While some inflammatory markers showed changes, LMPs and NMPs demonstrated superior predictive accuracy (AUCs of 0.888 and 0.973, respectively) compared to traditional markers.
Conclusions:
- Elevated LMPs and NMPs in the early febrile stage are significant indicators of infection in super-elderly patients.
- MPs show promise as sensitive early warning biomarkers for infection in this vulnerable population.
- MPs offer a valuable tool for early infection detection and monitoring in super-elderly individuals.
