Association between salivary human leukocyte antigen-DR concentration and early childhood caries

Early childhood caries (ECC) is a prevalent, multifactorial disease influenced by microbial factors and host immune factors. Saliva serves as a noninvasive diagnostic medium with the potential to detect immune biomarkers such as human leukocyte antigen-DR (HLA-DR), a key class II molecule of the major histocompatibility complex involved in antigen presentation and the activation of adaptive immune responses.

To evaluate and compare salivary HLA-DR levels in preschool children with and without ECC and assess the relationship between HLA-DR levels and deft scores.

This cross-sectional study was conducted among preschool children aged 3-6 years attending school dental screening camps.

Forty children aged 3-6 years were included and divided into ECC ( n = 20) and caries-free ( n = 20) groups. Caries status was assessed using World Health Organization criteria and the Deft Index. Unstimulated saliva samples were collected and analyzed for HLA-DR concentrations using a commercially available sandwich enzyme-linked immunosorbent assay. Intergroup comparisons were performed using the Mann-Whitney U -test, and associations were evaluated using Spearman's correlation.

Children with ECC showed significantly higher salivary HLA-DR levels (median 10.31 pg/mL, interquartile range [IQR]: 7.65-17.98) than caries-free controls (median 6.28 pg/mL, IQR: 3.14-9.32) ( P = 0.023). A weak positive but nonsignificant correlation was found between HLA-DR levels and deft scores (ρ =0.236, P = 0.317).

Elevated salivary HLA-DR levels in ECC suggest enhanced local immune activation and may serve as a noninvasive biomarker for ECC presence, although not a direct indicator of lesion severity.