Assessing the levels of immunoglobulins in the saliva of diabetic individuals with periodontitis using checkerboard immunodetection

Background: Current methods for determining salivary antibodies are cumbersome for large-scale screenings. Objectives: To test checkerboard immunodetection for monitoring salivary antibodies and to profile them in diabetic individuals with periodontitis. Methods: Salivary anti-Porphyromonas gingivalis, anti-Actinobacillus actinomycetemcomitans and total IgA levels of 10 individuals were compared using checkerboard immunoblotting and enzyme-linked immunosorbent assay (ELISA). Results: Close correlation between both methods was found in anti-P. gingivalis IgA and total IgA, but not in anti-A. actinomycetemcomitans IgA, because of high background levels in ELISA. Thereafter, checkerboard immunodetection was used to compare salivary antibodies of 20 adult type II diabetic with 32 non-diabetic individuals with (n = 22) or without (n = 10) periodontitis. Patients with periodontitis (regardless of their diabetic condition) expressed increased levels of total IgA in both whole and parotid saliva, but reduced levels of anti-A. actinomycetemcomitans IgA in whole saliva. Consequently, the proportion of anti-A. actinomycetemcomitans IgA in the total IgA was lower in saliva of patients with periodontitis compared with healthy controls. Conclusions: Checkerboard immunodetection was reliable and economical for screening saliva samples for multiple antibody reactions. Our results support previous reports which suggested that patients with periodontitis are able to secrete high levels of salivary Ig, but are hampered in targeting their salivary response toward A. actinomycetemcomitans.