OBJECTIVETo study the variations of protein concentration in saliva stimulated and its effect on clinical diagnosis.

METHODSThe saliva from 33 normal controls and 73 patients with Sjögren syndrome (SS) who were stimulated with acid and not were collected. The concentration of beta 2 microglobulin (beta 2-mG), secretory immunoglobulin A (SIgA), and pH were measured by Radioimmunoassay, Rate Nephelometry and pH Detection Paper, respectively. SPSS 10.0 was used to determine the mean statistical differences among these groups.

RESULTSIn patients with SS, the concentration of beta 2-mG in saliva stimulated with Vc was significantly lower compared with that in saliva not stimulated (P < 0.01); In saliva stimulated with Vc, the concentration of beta 2-mG in patients with SS was higher than that in normal controls (P < 0.05). In normal controls, compared with that in saliva not stimulated, flow rate in saliva stimulated with 3% acetic acid and Vc was significantly higher (P < 0.01) and pH, concentration of beta 2-mG and SIgA were significantly lower (P < 0.01 and P < 0.05 respectively); there was a significant difference of flow rate, beta 2-mG, SIgA and pH in saliva between the subjects stimulated with 3% acetic acid and with Vc (P < 0.01).

CONCLUSIONSThe reason for the decrease of protein concentration in saliva stimulated may be the increase of flow rate caused by the decrease of pH or the decrease of pH itself. Protein detection of saliva stimulated in patients with SS is helpful in diagnosis, but the criterion is different between the saliva stimulated and not stimulated.