An Impairment of Salivary Gland Function in Rheumatoid Arthritis: Association with Change in Salivary Biomarkers and Disease Activity

Abstract

Background: Rheumatoid arthritis is a chronic inflammatory autoimmune disease characterized by jointinflammation, involvement of exocrine salivary and lacrimal glands may occur as extra-articular manifestations in thisdisease. This study aimed to provide evidence of altered in function and composition of salivary gland in patientswith rheumatoid arthritis by determine salivary flow rate and some biochemical parameters(total protein, amylase,peroxidase) and to investigate the relationship between disease activity and changes in function and compositionof salivary gland.Materials and Methods: Fifty five patients with RA (7 males and 48 females) were enrolled in this study with age range(20-69) years. The patients were separated into two groups in proportion to their salivation: normal salivation group(37) and hypo salivation group (18). Thirty five (9 male and 26 female) apparently healthy volunteers were alsoparticipated in the study. Three ml of unstimulated saliva was collected from all patients and control to determinesalivary flow rate on one hand and salivary total protein, α-amylase and peroxidase by colorimetric method on otherhand.Results:Resultsshowed that there is highly significant decrease (P< 0.01; p< 0.001) in the median salivary levels of (flowrate, total protein, α-amylase and peroxidase) among RA patients when compared to control. There was highlysignificant reduction (P< 0.01) in median salivary levels of flow rate, total protein, α-amylase and peroxidase in twostudy groups (normal salivation and hypo salivation) as compared to that in control group. Also the levels of all theseparameters (sialometry and sialochemistry) were significantly decrease (P =0.00) in RA patients with hypo salivationas compared to that in patients with normal salivation. There was strong positive correlation between total proteinand salivary flow rate (r= 0.651, P=0.000), in one hand, and on the other hand, there was strong positive correlationbetween α-amylase and both salivary flow rate (r=623, P= 0.000) and total protein r=658, P=0.000).Conclusion: These findings indicate that the changes in salivary composition may represent involvement of salivaryglands in patients with rheumatoid arthritis.