CHEMOKINE EXPRESSION AND LEUKOCYTE INFILTRATION IN SJOGRENS-SYNDROME

Objective. To investigate the expression and source of chemokines in m inor salivary gland biopsies (MSGs) in patients with Sjogren's syndrom e (SS). Methods. Immunohistochemical analysis was used to determine th e pattern of chemokine expression in MSGs from patients with (n = 6) a nd without (n = 5) SS, as well as to examine the phenotype of both res ident and infiltrating cells expressing chemokines. Results. Significa nt differences in the number of infiltrating mononuclear (MN) cells in patients with and without SS were noted. Ductal epithelial cells of S S biopsies expressed significantly increased levels of macrophage infl ammatory protein (MIP)-1 alpha, MIP-1 beta, interleukin-8 (IL-8) and R ANTES (Regulated upon Activation, Normal T cell Expressed and Secreted ). Biopsies from patients with SS showed that MIP-1 beta was expressed by 51% of infiltrating cells, while 41% expressed MIP-1 alpha, wherea s 22 and 7% expressed RANTES and IL-8, respectively. Conclusion. Chemo kines expressed by ductal epithelial cells may attract circulating leu cocytes, in particular CD4(+) T cells, towards the site of inflammatio n, thereby orchestrating the influx of MN cells characteristically see n in MSGs in SS. Chemokines may be induced directly by a putative trig gering agent for SS, or secondary to the release of pro-inflammatory c ytokines produced by epithelial cells. These findings further implicat e epithelial cells as playing a major role in the pathogenesis of SS a nd implicate chemokines in the leucocyte recruitment in this setting.