Neutrophil CD64: a potential biomarker for the diagnosis of infection in patients with haematological malignancies

Aim: To investigate the role of neutrophil CD64 in diagnosing infection in patients with haematological malignancies. Methods: The clinical data of 76 patients with haematological malignancies and infection who were treated in our department between January 2014 and October 2019 were retrospectively analysed. To evaluate the diagnostic value of some biomarkers, infection indexes such as white blood cell count (WBC), neutrophil count (NEUT), neutrophil CD64 and procalcitonin (PCT) were compared across the patients with confirmed infection status and infection-control status. Sensitivity, specificity and area under the receiver operating characteristic curve (AUC) were also determined. Results: The WBC and NEUT did not differ significantly, whereas the neutrophil CD64 and PCT levels were significantly elevated in patients with a confirmed infection status (p < 0.05), with sensitivity of 31.0%, 45.2%, 76.2% and 50%, respectively, and specificity of 90.5%, 69%, 71.4% and 64.3%, respectively. The AUC of WBC, NEUT, neutrophil CD64 and PCT was 0.528, 0.517, 0.844 and 0.599, respectively. Further highlighting their diagnostic value, the neutrophil CD64 and PCT levels in neutropenia patients were significantly upregulated in patients with infection status (p < 0.05) but the WBC and NEUT were unchanged, with sensitivity of 73.7%, 63.2%, 68% and 68.4%, respectively, and specificity of 68.4%, 52.6%, 57.9% and 63.2%, respectively. The AUC of neutrophil CD64, PCT, WBC and NEUT was 0.864, 0.593, 0.419 and 0.403, respectively. Conclusion: These results indicate that neutrophil CD64 is a promising biomarker with superior sensitivity and specificity for diagnosing infection in patients with haematological malignancies, especially neutropenia patients.