Salivary Lactoferrin Levels and Polymorphisms in Down Syndrome Individuals with Periodontitis

Background/Objectives: Lactoferrin, a protein involved in the immune response, plays a significant role in the etiopathogenesis of periodontitis in the general population. This cross-sectional study aims to determine the salivary concentration of lactoferrin in Down syndrome individuals with periodontitis. Methods: A convenience cohort of 76 Down syndrome individuals was established, including 34 with periodontitis, 29 with gingivitis, and 13 with healthy gums. Unstimulated saliva samples were collected and processed to quantify the lactoferrin concentration using the Human Lactoferrin ELISA kit, the total protein concentration (bicinchoninic acid assay [BCA]) using the BCA Protein Assay Kit (Pierce, Rockford, IL, USA), and the lactoferrin/BCA ratio. Additionally, the Lf rs1126478 (140A/G in exon 2, Lys/Arg) genotypes were determined via PCR with restriction fragment length polymorphism (RFLP) analysis using the Earl enzyme. Results: The lactoferrin levels were comparable across patients with periodontitis, gingivitis, and healthy gums (median = 8.20, 6.57, and 7.61 µg/mL, respectively). There were no differences in the BCA levels between the three groups (median = 2.21, 3.17, and 2.08 µg/µL, respectively) nor in the lactoferrin/BCA ratios. The distribution of the Lf 140A/G polymorphism did not show differences concerning periodontal health status. Conclusions: In Down syndrome individuals, salivary lactoferrin and BCA levels are not influenced by the periodontal health condition. Additionally, no significant genetic associations were found with the rs1126478 polymorphism in Down syndrome individuals with and without periodontitis. Lactoferrin production in Down syndrome may not be upregulated in response to periodontal pathogens, which could be indicative of an immune system dysregulation contributing to the early onset and severity of periodontitis in this population.