Levels of plasmacytoid dendritic cells and type-2 myeloid dendritic cells are reduced in peripheral blood of patients with primary Sjögren's syndrome

Abstract

Patients with pSS have alterations among DC populations in PB, and pDC are present in the SG, suggesting a potential role of these cells in SS.

Activation of the type I interferon pathway in primary Sjogren’s syndrome

“…A greater number of IFNa-producing PDCs compared to control tissues were detected in pSS MSG biopsies [14,24]. PDCs as well as the mDC2 subset of myeloid dendritic cells have been shown to be reduced in the peripheral blood from these patients compared to controls, implying their influx into MSG target tissues [25]. A similar situation is described in a wide array of autoimmune disorders.…”

The complexity of Sjögren's syndrome: Novel aspects on pathogenesis

“…The locally increased IFN signature has later been confirmed along with the presence of pDC in the salivary glands by direct staining with CD123 and BDCA-2 pDC markers [44]. Besides the occurrence of pDC in the inflammatory foci, reduced levels of pDC were found in peripheral blood from patients with Sjögren's syndrome [45,46], suggesting the recruitment of pDC to the target organ, but a direct connection still needs to be established. The increased IFN signature in patients with Sjögren's syndrome seems not to be only locally restricted to the salivary glands, as a recent study identified an increased expression of IFN inducible genes also in monocytes from Sjögren's syndrome patients [45].…”

“…CD83 is expressed only on activated DC, whereas CD1a is predominately known as a marker for Langerhans cells, a certain type of dermal DC, as well as monocyte-derived DC. Decreased levels of the CD141 + mDC2 subset were found in peripheral blood from patients with Sjögren's syndrome [46]. Nevertheless, it still needs to be proven whether mDC2 are actually present in the salivary glands of these patients.…”

Immune regulation and B-cell depletion therapy in patients with primary Sjögren’s syndrome

“…Serum levels of IFNa were increased in only some pSS patients and IFNa-mRNA levels were only slightly elevated in peripheral blood cells compared to controls [11,12]. Plasmacytoid dendritic cells (pDCs) are main producers of IFNa and these cells were demonstrated in the salivary glands of pSS patients, but not in controls [13,14]. Since reduced levels of pDCs were found in peripheral blood from patients with pSS, the findings suggest that pDCs are recruited into the salivary glands and are involved in disease pathogenesis [14].…”

“…Plasmacytoid dendritic cells (pDCs) are main producers of IFNa and these cells were demonstrated in the salivary glands of pSS patients, but not in controls [13,14]. Since reduced levels of pDCs were found in peripheral blood from patients with pSS, the findings suggest that pDCs are recruited into the salivary glands and are involved in disease pathogenesis [14]. Whether these cells are the major source of type I IFN in pSS patients is, however, not known and ductal epithelial cells likely contribute to (circulating) type I IFN levels [15].…”