Evaluation of the predictive performance of CD64 and CD69 markers in the early diagnosis of bloodstream infections

Bilir G., ŞİRİN M. C., Çetin E. S., ARIDOĞAN B.

Acta Clinica Belgica: International Journal of Clinical and Laboratory Medicine, 2026 (SCI-Expanded, Scopus)

Özet

Background: Bloodstream infection (BSI) is a leading cause of global morbidity and mortality. This study aimed to evaluate the predictive performance of CD64 and CD69, together with other cell surface markers, for early diagnosis of BSI and to compare them with conventional inflammatory markers. Methods: Expression levels of neutrophil and monocyte CD11b, CD14, CD64, and CD69 were measured by flow cytometry. Procalcitonin, C-reactive protein-to-albumin ratio, sTREM-1, calprotectin, and hematological ratios were also analyzed. Diagnostic performance was assessed using ROC analysis, and logistic regression, including Firth penalization, was performed to identify independent predictors of BSI. Results: Procalcitonin, C-reactive protein-to-albumin ratio, sTREM-1, calprotectin, neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, monocyte-to-HDL ratio, nCD11b, mCD11b, nCD14, mCD14, nCD64, mCD64, nCD69, and mCD69 differed significantly between the culture-confirmed BSI group (n = 130) and the culture-negative control group (n = 50) (p < 0.05). Among cell surface markers, mCD69 demonstrated the highest diagnostic accuracy (AUC = 0.948), followed by nCD14 (AUC = 0.897) and nCD64 (AUC = 0.884). The gram-negative bacteremia group exhibited the highest median values of procalcitonin, C-reactive protein-to-albumin ratio, sTREM-1, calprotectin, neutrophil-to-lymphocyte ratio, and nCD14, and the lowest median lymphocyte-to-monocyte ratio compared with the gram‑positive bacteremia and fungemia groups. Significant positive correlations were observed between cell surface markers and conventional inflammatory markers (p < 0.05). In logistic regression analysis, mCD69 and procalcitonin were statistically associated with BSI (p < 0.05). Conclusion: Cell surface markers, particularly mCD69, demonstrated good discriminatory performance between BSI and control groups. Their combined use with conventional markers may provide useful complementary information; however, future validation studies including alternative comparator groups are required before routine clinical implementation.