Pentraxin 3 Levels Reflect Inflammatory and Parasitic Activity in Human Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a severe zoonotic disease characterized by high mortality and a pronounced systemic inflammatory response. Although Pentraxin 3 (PTX3) has been implicated in infectious and inflammatory disorders, its role in human VL remains poorly defined, and host-derived indicators that simultaneously reflect inflammatory and parasitic activity are limited. This study investigated the association between plasma PTX3 levels, parasite load, and <i>PTX3</i> gene polymorphisms (rs1840680 and rs2305619) in patients with VL. An observational study was conducted between 2017 and 2021, including 36 patients with confirmed VL and 45 healthy controls matched by age and sex. Plasma PTX3 concentrations were determined by ELISA, parasite load by quantitative PCR (qPCR), and cytokines (IL-2, IL-6, IL-10, IL-17A, IFN-γ and TNF-α) by flow cytometry. PTX3 levels were significantly higher in VL patients than in controls (23.2 ng/mL vs. 0.80 ng/mL; <i>p</i> < 0.0001) and correlated positively with parasite load (r = 0.39; <i>p</i> = 0.02) and cytokines IL-6, IL-10 and IFN-γ. No associations were observed between <i>PTX3</i> polymorphisms and disease susceptibility. These findings suggest that PTX3 reflects both inflammatory responses and parasitic burden in VL and may serve as a potential indicator of disease activity.