Copyright © 2022 The Author(s); Published by Nickan Research Institute. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Immunopathol Persa. 2022;x(x):e29291 Original Platelet counts and C-reactive protein in preterm infants with patent ductus arteriosus Mohammad Reza Aramesh ID , Arash Malakian ID , Mohsen Hosseinzadeh ID , Masoud Dehdashtian ID , Mohammad Rostami Shahrebabaki * ID Department of Neonatal Intensive Care Unit, Imam Khomeini Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Immunopathologia Persa http www.immunopathol.com *Correspondence to Mohammad Rostami Shahrebabaki, Email: mohammaderostami@gmail. com, rostami.m@ajums.ac.ir Received 19 Sep. 2021 Accepted 9 Nov. 2021 Published online 9 June 2022 Keywords: Patent ductus arteriosus, Platelet, C-reactive protein, Preterm infants Introduction: Patent ductus arteriosus (PDA) is a common disorder in premature infants which causes heart failure. Platelets and C-reactive protein (CRP) play an important role in closure. Objectives: The purpose of this study was to evaluate serum CRP and plasma platelet count in preterm infants with PDA compared to infants without PDA. Patients and Methods: This case-control study was conducted on premature infants with PDA admitted to Imam Khomeini hospital in Ahvaz, Iran (2020-2021). A group of 120 infants with inclusion criteria was selected and divided into two groups of 60 subjects. The preterm infant with PDA and without PDA was defined as the case and control group, respectively. Platelet count, serum CRP, and an echocardiogram were assessed in all infants. The subjects were matched by gender, gestational age, and birth weight. Results: The mean platelet count was 194.67±74.03 (×10 3 /mm 3 ) in the neonate with PDA, and it was significantly lower than in neonate without PDA (P=0.04). The mean of serum CRP was significantly different in neonates with PDA (11.62±5.96 mg/L) compared to neonates with closed arterial ducts (8.52±3.97 mg/L; P=0.002). Additionally, PDA was associated with high platelet distribution width (PDW). Conclusion: The findings of this study revealed that PDA is associated with a low-number of platelets and high serum levels of CRP in preterm neonates. It is suggested that further studies with a higher sample size on platelet count and/or function be performed in PDA patients to understanding more about the cause of PDA and to discover novel and beneficial aims in these cases. Abstract Citation: Aramesh MR, Malakian A, Hosseinzadeh M, Dehdashtian M, Rostami Shahrebabaki M. Platelet counts and C-reactive protein in preterm infants with patent ductus arteriosus. Immunopathol Persa. 2022;x(x):e29291. DOI:10.34172/ ipp.2022.29291. Introduction The ductus arteriosus is the connection between the aorta and the pulmonary artery and is necessary for the fetus survival (1). After birth, this duct must be closed due to changes in the fetal to neonatal blood circulation (2). Ductal closure failure in premature babies is a mystery that infants have confronted for a long time, while the pathophysiological and scientific consequences have not yet been resolved (3-5). The exact mechanism of ductal constriction remains controversial (6). Patent ductus arteriosus (PDA) is the main challenge in preterm infants in neonatal intensive care units (7). Additionally, the endurance of PDA in premature infants causes severe hemodynamic modifications that sometimes result in death(8). Several previous studies suggested that inflammation plays a critical function in the pathogenesis of PDA (9, 10). It has been shown that serum C-reactive protein (CRP) levels are higher in preterm infants with PDA Key point Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases that causes serious hemodynamic changes and sometimes leads to death in preterm neonates. Based on our findings, PDA is associated with a low number of platelets and high levels of C-reactive protein in preterm neonates. (9). Moreover, several studies have reported that impaired platelet linkage or transgenic failings in its biogenesis lead to determine of ductus arteriosus (7). Echtler et al showed an essential role of platelets in postnatal ductus arteriosus closure in a mouse model. They also reported that thrombocytopenia may have a critical role in rising the risk for failure of ductus arteriosus closure in premature newborns(11). There is few human studies on the association of CRP and platelet levels with PDA (1). Objectives Considering the importance of this disease, we decided to conduct this study with the DOI:10.34172/ipp.2022.29291