Search

The oral cavity is exposed to a variety of environmental insults. Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. Human beta-defensins (hBD) are antimicrobial peptides that are a component of the innate immune response; they are expressed in epithelia and are proposed to have a role in mucosal defense. hBD-1 mRNA is constitutively expressed in numerous mucosal tissues, including human gingiva and submandibular and parotid glands. Our objective was to detect the expression and localization of hBD-1 peptide in human salivary glands and in saliva. Minor salivary gland tissue was obtained from biopsies of patients with mucoceles (n = 20). hBD-1 peptide was detected by immunohistochemistry; expression was localized to the ductal cells and not the acinar cells of these glands. The peptide was located apically, toward the lumen in the duct cells. Further evaluation showed stronger hBD-1 expression in ducts with periductal inflammation, as indicated by the immunostaining of serial sections with anti-CD45 specific for B- and T-lymphocytes. Statistical analysis showed a strong correlation of hBD-1 staining and inflammation. Results of immunolocalization suggest that hBD-1 functions to protect salivary glands from retrograde infection, that expression of the peptide is enhanced in inflamed sites, and that post-transcriptional regulatory mechanisms may be involved in hBD-1 peptide expression. Western immunoblot analysis also detected hBD-1 peptide in unstimulated, whole, acidified saliva from normal volunteers. However, hBD-1 peptide associated with salivary mucin resulted in loss of the detection in a dot-immunoblot assay. Association of hBD-1 with salivary mucin may facilitate peptide distribution and adherence to oral surfaces and aid its function within the oral cavity.

Whole saliva samples and lip biopsies were collected from 12 allogeneic bone marrow transplant recipients who developed extensive chronic graft-versus-host disease (GVHD) and from 10 healthy allogeneic and syngeneic recipients without GVHD. Six of ten biopsies from patients with chronic GVHD had lichenoid stomatitis or sialadenitis, or both, with sialodochitis. Seven of nine biopsies from patients free of chronic GVHD were entirely normal, and two had either mild glandular or mucosal changes. Salivary gland involvement in chronic GVHD was associated with decreased or absent levels of salivary IgA and inorganic phosphate, decreased salivary flow rates, and increased concentrations of salivary sodium, albumin, and IgG. The most striking abnormalities were found in patients with histologic evidence of sialadenitis. In contrast, marrow transplant recipients without chronic GVHD had normal salivary immunoglobulin and electrolyte levels. Secretory IgA deficiency may contribute to the frequent sinobronchial infections observed in patients with chronic GVHD.

Labial minor gland salivary flow rate and sodium concentration were analyzed in relation to 1) histologic findings in labial biopsy specimens and 2) the occurrence of chronic graft-versus-host disease (GVHD) in patients who received bone marrow transplants. Biopsy specimens and samples were obtained from 61 recipients of marrow transplants (including three twins) 51 to 1,260 days post transplantation. Labial saliva sodium concentrations were elevated in some patients, and these increases were associated with inflammation and destruction of minor salivary gland acini and ducts by chronic GVHD or other factors. The predictive value of the salivary sodium changes in evaluating labial salivary gland pathologic changes was 91 per cent, and the sensitivity was 74 per cent. Thus, if a transplant recipient is found to have an elevated labial saliva sodium level, then the probability that he has pathologic labial gland changes is 91 per cent. When analyses were restricted to include only patients who received no irradiation during transplantation, then elevated labial saliva sodium concentration was significantly associated with the occurrence of chronic GVHD. The sensitivity of this relationship was 42 per cent, but the predictive value was 100 per cent. Thus, if a nonirradiated transplant recipient is found to have an elevated labial saliva sodium concentration, then it is virtually certain that he has chronic GVHD. We found no significant changes in labial saliva flow rates in these bone marrow transplant recipients.