Evaluation of serum presepsin,pentraxin-3 and neopterin levels before and after treatment in childhood lower respiratory tract infections

Objective: This study aimed to evaluate the levels and diagnostic value of classical (CRP, WBC, NLR, lactate) and novel biomarkers (presepsin, pentraxin-3, neopterin) in pediatric patients diagnosed with lower respiratory tract infections, in order to assess the presence of infection and the response to treatment. Materials and Methods: The study included 43 children diagnosed with lower respiratory tract infection and 45 children without signs of infection as the control group. In the patient group, levels of presepsin, pentraxin-3, neopterin, CRP, WBC, NLR, and lactate were measured before and after treatment and compared with the control group. Results: All biomarker levels were significantly higher in the patient group before treatment compared to the control group. Post-treatment levels of CRP (from 3.79 to 0.94 mg/dL), WBC (from 13.73 to 10.53 x10³/μL), NLR (from 2.86 to 0.68), lactate (from 2.02 to 1.51 mmol/L), neopterin (from 4.05 to 3.59 nmol/L), pentraxin-3 (from 2.66 to 2.08 ng/mL), and presepsin (from 91.76 to 85.81 ng/L) showed a statistically significant decrease (p<0.001). Conclusion: While classical inflammatory markers such as CRP, WBC, NLR, and lactate effectively reflect the presence of infection, neopterin and pentraxin-3 were identified as sensitive indicators for infection progression and treatment response. Presepsin may play a supportive role in detecting bacterial infections. These findings suggest that the use of multiple biomarkers can be valuable in the diagnosis and follow-up of lower respiratory tract infections in children.