Correlation between human neutrophil peptide 1–3 secretion and azurophilic granule (CD63) expression in early childhood caries

Abstract

Background: In saliva, neutrophil constitutes the most prominent first‑line defense of immune
cells against pathogenic microbes. The importance of neutrophils to the host immune systems of
neutropenic or patients disabled with regard to their neutrophil function results in a tendency
toward serious infections, such as early childhood caries (ECC). The cytoplasmic granules present
in neutrophils play a major role in neutrophil‑mediated inflammation. Azurophilic granules contain
antimicrobial proteins, such as defensin, a human antimicrobial peptide (HNP 1–3). The aim of this
study is to analyze the correlation of HNP 1–3 secretion with CD63 expression on the surface
of salivary neutrophils.
Materials and Methods: This study constituted a cross‑sectional, analytical observational study.
Saliva taken from preschoolchildren between the ages of 4–6 years who had been divided into
two groups, i.e., early childhood caries group with decayed, extracted, filled teeth (def‑t) index >6
and caries free with def‑t = 0, was subjected to a HNP 1–3 secretion test using ELISA assay and an
expression test for CD63 by means of a flow cytometry test. The results obtained were analyzed
using independent t‑test and Pearson correlation (P < 0.05).
Results: The secretion of HNP 1–3 in the saliva of ECC was higher (172.6 ± 41.64) compared to
that of caries‑free cases (140.39 ± 31.91), whereas the level of CD63 salivary expression in ECC
was lower (2.32 ± 0.57) than in the presence of caries (2.67 ± 0.46).
Conclusion: In ECC cases, saliva increases HNP 1–3 secretion but decreases CD63 expression
on the surface of salivary neutrophils.
Key Words: CD63, dental caries, human antimicrobial, neutrophils