The clinical significance of intercellular adhesion molecule-1 (ICAM-1) levels in blood of patients with influenza

An excessively pronounced inflammatory response and endothelial dysfunction play a key role in the development of severe and complicated forms of influenza. Objective. To evaluate the role of plasma ICAM-1 in the development of severe influenza forms and in disease prognosis. Patients and methods. A total of 59 patients with influenza, aged 37 to 90 years, who received inpatient treatment between January and April 2025, were examined. Group 1 consisted of 29 patients with uncomplicated influenza, Group 2 – 30 patients whose disease was complicated by pneumonia, and the control group – 10 healthy individuals of comparable age. Among the pneumonia patients, 14 (23.7%) had a fatal outcome. Plasma ICAM-1 levels were measured once during the acute phase of the disease. Results. Elevated blood ICAM-1 levels were detected in patients with influenza complicated by pneumonia: the median was 3.2 times higher than in the control group (p = 0.004). In uncomplicated influenza, ICAM-1 values did not statistically differ from those in the control group (p = 0.2). Among deceased patients, plasma ICAM-1 levels were higher than among survivors (p = 0.01). An ICAM-1 level in blood >700 ng/mL increased the risk of fatal outcome by 8-fold. Conclusion. Elevated plasma ICAM-1 levels are observed exclusively in patients with influenza complicated by pneumonia. The association between high blood ICAM-1 levels and an unfavorable outcome underscores the importance of measuring this parameter for disease prognosis assessment. Key words: endothelial dysfunction, influenza, ICAM-1, pneumonia