Absence of salivary CCL28 in primary Sjögren's syndrome

CCL28 is a mucosa-associated epithelial-cell-produced chemokine involved in oral defense. We assessed the level of CCL28 in saliva of primary Sjögren's syndrome (pSS) patients in comparison with healthy controls and correlated it with IgA salivary levels. We included 30 non-smoker pSS patients and 30 non-smoker healthy controls paired by age (±5 years). Saliva samples were collected during the morning and kept frozen at -86 °C until the analysis. Fifty microliters of saliva was diluted 3:1 with water and analyzed for CCL28 salivary levels by ELISA method. The samples were tested in triplicate. IgA salivary levels were tested by ELISA method. We used descriptive statistics, Mann-Whitney U test and Kendall's tau correlation coefficients. pSS patients were mostly females (93.3 %), mean age 54.5 ± 13.3 years and median disease duration of 7.6 years (0.5-33). Patients with pSS had lower levels of salivary CCL28 when compared with controls [0 (0-1,272 pg/ml) vs. 94.4 (0-5,810) pg/ml, p < 0.0001]. pSS patients also had lower median levels of salivary IgA [72.55 μg/ml (0.40-297.4)] than controls [131.9 μg/ml (6.8-281.8)], although the latter results did not reach statistical significance (p = 0.51). Among the SS group, there was no correlation between CCL28 and IgA salivary levels nor between salivary IgA and disease duration, salivary flow, serum immunoglobulins or dental loss. CCL28 was absent in saliva of pSS patients; however, this finding did not correlate with salivary IgA levels.