A decrease of human leucocyte antigen-DR expression on monocytes in peripheral blood predicts stroke-associated infection in critically-ill patients with acute stroke.

BACKGROUND AND
PURPOSE: To investigate changes in human leucocyte antigen (HLA)-DR expression on peripheral monocytes, determine the value of predicting the development of stroke-associated infection (SAI), and determine the correlation with other conditions in critically-ill patients in the neurological intensive care unit (NICU) who suffered an acute stroke.
METHODS: All patients were enrolled consecutively and admitted to NICU within 24 h after the onset of symptoms. Patients were followed in order to identify whether infection developed and determine survival status within 2 weeks after the stroke. Patients were divided into stroke or control group by study design, infection or non-infection group by whether or not they had an infection, survival or death group by prognosis and cerebral infarction or cerebral haemorrhage group by stroke type. Patients in which acute stroke was excluded by head CT or MRI were admitted to general ward and were used as a control group. Blood samples were collected serially on days 1, 2, 4, 6 and 14 after stroke, then monocyte human leucocyte antigen-DR (HLA-DR) expression was determined by flow cytometry. The National Institute of Health Stroke Scale (NIHSS), Acute Physiology and Chronic Health Evaluation II (APACHEII) and Glasgow Coma Scale (GCS) scores were recorded over the course of observation.
RESULTS: Fifty-three subjects and 39 controls were enrolled in the study. On days 1, 2, 4, 6 and 14, there was a significant difference in monocyte HLA-DR expression between stroke group and control group (all P < 0.001), but no difference was found between ischaemic stroke group and haemorrhagic stroke group (all P > 0.05). The infection group compared with non-infection group did not exhibit a significant difference in HLA-DR expression on days 1 and 2 (all P > 0.05), but significant differences emerged on days 4, 6 and 14 (all P < 0.01). On days 1 and 2 the HLA-DR expression in the survival group compared with death group, was not significantly different (all P > 0.05), but differences became significant on days 4 and 6 (P < 0.01). On day 1, HLA-DR expression <62.80% had the predictive value to SAI (sensitivity 83.3%, specificity 55.2%, AUC = 0.661, P = 0.031) and on day 2, HLA-DR expression <57.83% had the predictive value to SAI (sensitivity 95.8%, specificity 79.3%, AUC = 0.907, P = 0.000) in acute stroke patients. A statistically significant inverse correlation was found between NIHSS and HLA-DR on days 2 and 4 during the observation period (all P < 0.01), but there was no statistically significant negative correlation on days 1, 6 or 14 (all P > 0.05). HLA-DR expression did not correlate with APACHEII (all P > 0.05) or GCS (all P > 0.05) during the measurement period.
CONCLUSIONS: Human leucocyte antigen-DR (HLA-DR) expression decreases and sustains a dynamic change and it also relates to the severity of patient's condition in the critically-ill patients with stroke. Progressively persistent low monocyte HLA-DR expression is associated with a poor prognosis. The decline in HLA-DR expression contributes to infection in critically-acute stroke patients. Monitoring of monocyte HLA-DR expression may be useful for identifying patients suffering from acute stroke who are at high risk for infection.