The frequency and phenotype analysis of peripheral pDC in pSS
patients
We first analyzed the frequency of pDC in PBMCs from treatment-naïve pSS
(n=31), HCQ-treated pSS (n=17), SLE (n=9), and HCs (n=29) by flow
cytometry. The demographic characteristics of all the included pSS
patients were demonstrated in Supplementary Table 2 and SLE patients
were demonstrated in Supplementary Table 3. The gating strategy of pDCs
was shown in Figure S1a. In accordance with previous studies [20,
26], the percentage of pDCs was significantly lower in PBMCs from
treatment naïve SLE and pSS patients compared with HCs. Interestingly,
the reduction of pDCs rebounded in pSS patients after
Hydroxychloroquine (HCQ) therapy
(Fig 1a). However, we did not observe the hyperactivation status of pDCs
in pSS as the activation markers CD80, CD83, and CD86 expressions were
equal to HCs (Fig 1b, Fig S1c).
Detection of TLR7/9 expressions showed that unstimulated pDCs from pSS
patients showed higher TLR7 but not TLR9 expressions compared with HCs
(Fig 1c, d). However, the difference vanished after TLR7 (R848) or TLR9
ligand (ODN2216) stimulation (Fig 1e, f).