Elevated P-RBC complexes are associated with thrombotic risk and diagnostic potential in myeloproliferative neoplasms: a retrospective cohort study.

BACKGROUND: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by excessive myeloid proliferation. The impaired clearance of senescent erythrocytes is a key pathological feature, yet its mechanisms remain unclear. Pro-phagocytic platelet-erythrocyte (P-RBC) complexes may represent a novel intercellular interaction involved in this process. OBJECTIVE: To investigate the levels of P-RBC complexes in MPN patients, their association with clinical characteristics and thrombotic risk, and their potential diagnostic value. METHODS: In this retrospective cohort study, 152 MPN patients (including polycythemia vera [PV], essential thrombocythemia [ET], and primary myelofibrosis [PMF]) and 152 healthy controls were enrolled. P-RBC complex levels in peripheral blood were measured using flow cytometry. Correlations with laboratory parameters, thrombotic events, and survival were analyzed. RESULTS: P-RBC complex levels were significantly higher in MPN patients than in controls (2.76 ± 0.53% vs. 1.28 ± 0.37%, P < 0.001). Levels varied by subtype, with PMF patients showing the highest levels (3.28 ± 0.52%), followed by PV (2.76 ± 0.44%) and ET (2.49 ± 0.39%) (P < 0.001). P-RBC levels positively correlated with hemoglobin (r = 0.456), C-reactive protein (r = 0.291), and lactate dehydrogenase (r = 0.736) (all P < 0.001). Patients with thrombotic events had higher P-RBC levels than those without (3.04 ± 0.70% vs. 2.72 ± 0.48%, P = 0.009). Multivariate analysis identified P-RBC level as an independent risk factor for thrombosis (OR = 3.07, P = 0.012). Although survival was worse in the high-P-RBC group, the difference was not statistically significant (P = 0.194). ROC analysis showed excellent diagnostic performance for MPNs (AUC = 0.990), with 100.0% sensitivity and 91.4% specificity at a 1.80% cutoff. CONCLUSION: P-RBC complexes are significantly elevated in MPN patients and correlate with disease subtype, inflammation, and thrombotic risk. They represent a promising novel biomarker for MPN diagnosis and risk stratification.