The expression of IL-21 in the LSG of SS patients and the severity of inflammation. The labial salivary gland specimens of the primary SS patients were divided according to the grade (1 to 4) of lymphocytic infiltration (see Methods). (a) This specimen was obtained from a SS patient who fulfilled the American-European Consensus Group Criteria except LSG biopsy. There were no definite lymphocytic foci but moderate lymphocytic infiltration was observed. (a-c) IL-21 expression increased as the lymphocytic infiltration in the salivary gland became more severe. (d) IL-21 positive cell number was significantly increased in LSG from SS patients than in control. (e) Relationship between IL-21 positive cell number and inflammation severity. IL-21 positive cell number was elavated with grade (r = 0.521, P = 0.038). Horizontal bars represent the median of all samples within a group. Representative data are shown. IL-21: Interleukin-21; LSGs: labial salivary glands; SS: Sjögren's syndrome.