Salivary humoral immunity parameters in chronic inflammatory periodontal diseases: clinical and laboratory analysis

Abstract

Infectious and inflammatory periodontal diseases are among the common causes of tooth loss, highlighting the need for accessible biomarkers for diagnosis and monitoring. Saliva is a bioinformative material; however, the diagnostic relevance of immunoglobulins in gingivitis and periodontitis remains unproven. Purpose — To assess the association between salivary IgA, IgM, IgG and secretory sIgA levels and clinical signs of periodontal pathology. Materials and methods. A total of 600 residents of Khabarovsk Krai from key WHO age groups were examined; groups were formed on an ordinal scale: healthy, gingivitis, and mild, moderate, and severe periodontitis. The following were performed: assessment of clinical indices OHI-S, CPITN, PMA, and PBI; microbiological examination of pathological periodontal pockets; and measurement of salivary IgA, IgM, IgG and sIgA levels by ELISA. Results. Spearman correlation analysis showed a strong positive association between periodontitis severity and CPITN (ρ=0.636), a moderate association with PBI (ρ=0.479) and PMA (ρ=0.434), reflecting the role of inflammation and bleeding in disease progression; and a weak association with OHI-S (ρ=0.246). According to ROC analysis, sIgA had a moderate diagnostic value in severe periodontitis (AUC=0.72). The optimal sIgA cut-off was 305 mg/L, with sensitivity 78% and specificity 65%. The combination of sIgA and IgM in a multivariable logistic regression model showed high predictive performance (AUC=0.81). Each 1 mg/L increase in secretory sIgA increased the odds of periodontitis by 0.4% (OR=1.004). Between-group differences in salivary IgA, IgM, IgG and sIgA levels by disease severity were not statistically significant. A strong association with severe chronic periodontitis was demonstrated for the E. coli + Leptotrichia spp. combination (OR=3.00); significant predictors of severity included Enterococcus faecalis + Leptotrichia spp. (OR=2.34) and Staphylococcus aureus + Leptotrichia spp. (OR=1.92). Conclusion. Comparative analysis of OHI-S, CPITN, PMA and PBI indices, the microbiological profile of periodontal pocket associations, and humoral salivary biomarkers helps to clarify the contribution of individual parameters to the diagnosis and monitoring of infectious and inflammatory periodontal diseases.