495 - Gestational and Postnatal Age-Dependent Dynamics of Serum Thymus and Activation-Regulated Chemokine(TARC) Levels in a Large Single-Center Cohort of Neonates

Publication Number: 3477.495

Arika Murase, Fujita Health University Department of Pediatrics, Nagoya-city, Aichi, Japan; Yumiko ASAI, Fujita Health University, toyoake, Aichi, Japan; Shigemitsu Kamino, Department of pediatrics, school of medicene, Fujita health university, toyoake, Aichi, Japan; Chiharuko Nakauchi, Fujita Health University, Nagoya, Aichi, Japan; masahiko Manabe, Department of pediatrics,Fujita Health University, Toyoakeshi, Aichi, Japan; Arisa Kojima, Department of pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi, Japan; Yuri Kawai, Department of Pediatrics,Fujita Health of Sc, toyoake, Aichi, Japan; Masayuki Fujino, Department of pediatrics, Fujita Health University of School of Medicine, Toyoake, Aichi, Japan; Hiroko Boda, Departomento of Pediatorics. Fujita Health University, Toyoake, Aichi, Japan; Masafumi Miyata, Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi, Japan; Tetsushi Yoshikawa, Fujita Health University, Toyoake, Aichi, Japan

Background: Thymus and Activation-Regulated Chemokine (TARC) is a chemokine that recruits Th2 cells to sites of inflammation. In the neonatal, serum TARC levels have been reported to increase when the onset of Food protein-induced enterocolitis syndrome. However, there are no established reference ranges for TARC in newborns, and reports on its clinical utility remain scarce.

Objective: To evaluate the utility of serum TARC levels in the neonatal, we conducted a retrospective observational study.

Design/Methods: Serum TARC measurements were performed over time in newborns admitted to our NICU/GCU between April 2021 and March 2025. Statistical analysis was performed using EZR ver. 4.2.2.

Results: The study included 1315 newborns, of whom 734 (55.8%) were male. The overall median gestational age (GA) was 36 (22-42) weeks, and birth weight was 2472 (396-5005) g, respectively. Among these, 50 infants (3.8%) were extremely preterm (before 28 weeks), 200 (15.2%) were very preterm, 316 (24.0%) were late preterm, and 749 (56.9%) were term infants. Among these, 60 (4.5%) were very low birth weight infants and 88 (6.6%) were extremely low birth weight infants. There was no gender difference in serum TARC levels on the day of birth (DOB) (686.15 pg/mL vs. 714.88 pg/mL, p=0.357). Serum TARC levels showed a moderate positive correlation with both birth weight and GA (R=0.44: p< 0.001, R=0.497: p< 0.001). Although there was no difference in mean serum TARC levels between very low birth weight infants and extremely low birth weight infants (294.26 pg/mL vs 369.09 pg/mL, p=0.680), levels were significantly lower compared to low birth weight infants and normal birth weight infants (vs 681.44 pg/mL, p< 0.001 and vs 897.81 pg/mL, p< 0.001) at DOB. Repeated measures analysis of variance by GA from DOB to 7 days of life (DOL) showed that serum TARC levels significantly increased with longer GA and advancing DOL (GA p< 0.001, DOL p=0.025). Even as post menstrual age progressed, serum TARC levels in extremely preterm infants tended to remain lower compared to term infants.

Conclusion(s): Serum TARC levels in newborns significantly increased in proportion to GA and DOL. However, extremely preterm infants tended to maintain low levels even as their age progressed, suggesting a possible association with the maturation of immune systems. Future studies should examine comparisons by disease type, such as gastrointestinal complications, bronchopulmonary dysplasia, and by feeding method, such as breast milk versus formula.