{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T11:57:05Z","timestamp":1781697425014,"version":"3.54.5"},"reference-count":47,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T00:00:00Z","timestamp":1781222400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Background: Vitamin D, through its role in antimicrobial peptide (AMP) expression, may influence innate immunity and inflammation in urinary tract infections (UTIs). This study evaluated its role in patients with vesicoureteral reflux (VUR) and its contribution to the pathophysiology of reflux nephropathy (RN). Methods: We conducted a cross-sectional observational study of 25 pediatric patients with VUR, representing a subgroup analysis of a larger cohort examined in a previous study. We determined patients\u2019 vitamin D status, correlated it with recurrent UTIs and RS, and explored its relationship with urinary LL-37, NGAL, and IL-6 levels as markers of innate immune function. Results: Serum vitamin D levels ranged from 10.7 to 123.2 ng\/mL (mean 39.5 ng\/mL); 12% had deficiency and 20% had insufficient levels. Low vitamin D levels were detected in patients with more than five acute pyelonephritis (APNs), with a mean value classified as insufficient (27.3 ng\/mL). Patients with RS had a lower mean vitamin D level compared to those without (30.51 ng\/mL vs. 41.23 ng\/mL), though the difference was not statistically significant (p = 0.39). No significant associations were found between vitamin D and urinary IL-6 or NGAL levels. A strong positive correlation was observed between vitamin D and urinary LL-37\/creatinine (r = 0.78, r2 = 0.61). Conclusions: Vitamin D appears to influence the frequency of UTIs and the development of RS, primarily by modulating LL-37 secretion, suggesting a possible role in the pathophysiology of RN.<\/jats:p>","DOI":"10.3390\/children13060811","type":"journal-article","created":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T10:19:53Z","timestamp":1781691593000},"page":"811","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Role of Vitamin D in Modulating the Innate Immune Response in Children with Vesicoureteral Reflux"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-8023-2631","authenticated-orcid":false,"given":"Marius-Cosmin","family":"Colceriu","sequence":"first","affiliation":[{"name":"Discipline of Physiology, Department of Functional Biosciences, \u201cIuliu Ha\u021bieganu\u201d University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania"},{"name":"Second Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Diana","family":"Jecan-Toader","sequence":"additional","affiliation":[{"name":"Second Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"},{"name":"Medical Oncology Discipline, Department of Oncology, \u201cIuliu Hatieganu\u201d University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul Luchian","family":"Aldea","sequence":"additional","affiliation":[{"name":"Discipline of Public Health and Management, Department of Community Medicine, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bogdan","family":"Bulat\u0103","sequence":"additional","affiliation":[{"name":"Pediatric Nephrology, Dialysis and Toxicology Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dan","family":"Delean","sequence":"additional","affiliation":[{"name":"Pediatric Nephrology, Dialysis and Toxicology Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7022-6345","authenticated-orcid":false,"given":"Alina","family":"Grama","sequence":"additional","affiliation":[{"name":"Second Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"},{"name":"Second Pediatric Discipline, Department of Mother and Child, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra","family":"Mititelu","sequence":"additional","affiliation":[{"name":"Second Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"},{"name":"Second Pediatric Discipline, Department of Mother and Child, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4931-1219","authenticated-orcid":false,"given":"Tudor Lucian","family":"Pop","sequence":"additional","affiliation":[{"name":"Second Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"},{"name":"Second Pediatric Discipline, Department of Mother and Child, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400177 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0046-0803","authenticated-orcid":false,"given":"Simona","family":"Clichici","sequence":"additional","affiliation":[{"name":"Discipline of Physiology, Department of Functional Biosciences, \u201cIuliu Ha\u021bieganu\u201d University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Teodora","family":"Mocan","sequence":"additional","affiliation":[{"name":"Discipline of Physiology, Department of Functional Biosciences, \u201cIuliu Ha\u021bieganu\u201d University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania"},{"name":"Nanomedicine Department, Regional Institute of Gastroenterology and Hepatology, 400158 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreea-Liana","family":"Bo\u021b (R\u0103chi\u015fan)","sequence":"additional","affiliation":[{"name":"Pediatric Nephrology, Dialysis and Toxicology Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania"},{"name":"Faculty of Nursing and Health Sciences, Department 2, University of Medicine and Pharmacy \u201cIuliu Hatieganu\u201d Cluj-Napoca, 400023 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1038\/ncpendmet0716","article-title":"Unexpected actions of vitamin D: New perspectives on the regulation of innate and adaptive immunity","volume":"4","author":"Adams","year":"2008","journal-title":"Nat. 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