Pentraxin 3 as a Potential Biomarker of Invasive Fusariosis in Onco‐Haematological Patients

Objectives This study aimed to evaluate the clinical use of pentraxin 3 serum level as a biomarker for screening episodes of invasive fusariosis among high‐risk onco‐haematological patients. Methods We analysed 63 serum samples from patients with invasive mould diseases and controls, which had been collected between 2009 and 2021 and stored at the Special Mycology Laboratory of Universidade Federal de São Paulo, Brazil. Material included samples from eight patients with invasive fusariosis, nine with invasive aspergillosis, and control groups comprising 20 healthy individuals, eight neutropenic patients with acute myeloid leukaemia, and eight allogeneic haematopoietic stem cell transplant recipients without any concomitant infection, and 10 neutropenic individuals who developed a microbiologically documented gram‐negative bacteremia. PTX3 levels were quantified using an enzyme‐linked immunosorbent assay (ELISA), and statistical analyses were performed using SPSS Statistics v.28.0, California USA. Results The optimal PTX3 detection threshold was established at 10 pg/mL, with the highest levels observed in patients with invasive aspergillosis (5532.8 pg/mL) and invasive fusariosis (3718.1 pg/mL). Healthy controls revealed PTX3 levels ranging from 109.9 to 385.7 pg/mL. Significant differences were noted among all groups ( p < 0.001), with PTX3 levels exceeding 1000 pg/mL exclusively in patients with IMDs. Notably, high PTX3 serum levels were detected in four out of the eight samples that had been collected 1–5 days before the diagnosis of fusariosis by culture. Conclusions Our results suggest that serum PTX3 quantification holds significant potential for screening patients with suspected invasive fusariosis among onco‐haematological patients, similar to its role in invasive aspergillosis.