Early recognition of cardiac involvement and prediction of disease prognosis are essential for the management of inflammatory diseases such as multisystem inflammatory syndrome. This study aimed to investigate the role of Pentraxin-3 levels in identifying cardiac involvement and evaluating disease severity in patients with multisystem inflammatory syndrome.

The study included 56 multisystem inflammatory syndrome patients and 26 healthy children as a control group. The multisystem inflammatory syndrome group was divided into those with cardiac involvement (n = 34) and those without (n = 22), as well as those with clinically mild-moderate (n = 30) and severe (n = 26) multisystem inflammatory syndrome. Blood samples for measurement of Pentraxin-3 levels were obtained from all patients before treatment and from the healthy controls.

In the patient group, the mean age was 8.2 ± 4 years (range: 2–17 years), and the male-to-female ratio was 1.8. In the control group, these values were 9.5 ± 3.7 years (range: 2–16 years) and 1.9, respectively (p > 0.05). Plasma Pentraxin-3 levels were significantly higher in multisystem inflammatory syndrome patients compared to controls (7.1 ± 5 ng/mL vs. 2.9 ± 2.1 ng/mL, p = 0.001). Patients with cardiac involvement had a significantly higher median Pentraxin-3 level than those without (5.8 ng/mL vs. 4.1 ng/mL, p = 0.004). Severe disease was also associated with a higher median Pentraxin-3 level compared to mild-moderate disease (6.1 ng/mL vs. 4.4 ng/mL, p = 0.001). Pentraxin-3 level was negatively correlated with left ventricular ejection fraction and positively correlated with B-type natriuretic peptide, troponin.

Elevated Pentraxin-3 levels in multisystem inflammatory syndrome patients may help predict the clinical course of the disease and cardiac involvement. However, larger-scale prospective studies are needed to further elucidate this.