Title: 2826 - Salivary Peptidoglycan Recognition Proteins Levels are Increased During Chronic Periodontitis


Sivaraman Prakasam (Presenter)
Oregon Health & Science University

Li-jung Lin, Oregon Health & Science University
Evan Blackwell, Oregon Health & Science University
Jeremy Miller, Oregon Health & Science University
Shreya Sood, Oregon Health & Science University


Objectives: Peptidoglycan recognition proteins (PGRP) are group of secreted innate immune pattern recognition receptors. PGRP are antimicrobial proteins that have known host immuno-modulatory functions. There are four human isoforms of PGRPs, namely PGRP 1, 2, 3 & 4. Previously we showed that PGRP 3 & 4 gene expression were down-regulated in salivary epithelial cells of chronic periodontitis (CP) patients. Considering that these proteins are secreted, the salivary levels of PGRPs may serve as surrogate diagnostic biomarkers for CP.
Objective of this study is to quantify salivary levels of PGRP 1, 3 & 4 in CP subjects and compare it with healthy/gingivitis (HG) subjects.

Unstimulated whole saliva was collected from 100 subjects, in the morning, after refraining from eating/drinking for an hour. Subjects with any significant medical history that required long term anti-inflammatory or antibiotic treatments were excluded. Complete periodontal charting was done for all subjects. Salivary PGPR1, 3, & 4 levels, as well as levels of IL1β were estimated with ELISA from undiluted aliquots. Subjects were classified into two groups, namely HG (n=50) or CP (n=50) based on their clinical and radiographic assessment. Mann Whitney U test was used to estimate significance with a P value ≤ 0.05.

Results: PGRP 3 & 4 levels were significantly elevated in CP (2 fold). IL1β levels were also significantly elevated in CP (1.2 fold). PGRP1 levels although elevated in CP was not statistically significant. Salivary PGRP3 and PGRP4 levels were strongly correlated. Salivary PGRP1 and IL1β were weakly correlated.

Conclusions: Salivary PGRP 3 & 4 levels can potentially discriminate CP from HG. The elevated levels of PGRPs are likely an attempt by the host innate immunity to control the microbial burden. Considering that PGRPs are thought to modulate inflammation, the significance of these elevated levels in saliva on the disease process needs to be evaluated


Biomarkers PGRP1 (pg/ml) PGRP3 (pg/ml) PGRP4 (pg/ml) IL1β (pg/ml)
753.77 ± 602.18 1990.08 ±
246.35 ± 317.79 73.73 ± 63.60
939.24 ± 714.83 3488.87 ±
417.77 ± 467.69 98.50 ± 79.18
P value 0.10935 0.00181 0.00094 0.03836

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE