The proportion of CD161 on CD56 NK cells in peripheral circulation associates with clinical features and disease activity of primary Sjögren's syndrome.

OBJECTIVES

The purpose of this study was to examine the proportion of CD161 on CD56 natural killer (NK) cells in peripheral blood of primary Sjögren's syndrome (pSS) and investigate its clinical relevance of pSS.

METHODS

The proportion of CD56 NK cells and CD161 on CD56 NK cells was detected by flow cytometry in 31 pSS patients and 29 healthy controls (HCs). The correlations between the proportion of CD161CD56 NK cells and clinical features and disease activity of pSS were further analyzed. Meanwhile, we drew the receiver operating characteristic curve to evaluate the diagnostic value of CD161CD56 NK cells in pSS. In addition, we evaluated the differences in the effects of CD161 cells and CD161 cells in peripheral blood on the function of CD56 NK cells in 5 pSS patients.

RESULTS

The proportion of CD56 NK cells and CD161CD56 NK cells decreased markedly in pSS patients compared to HCs. The correlation analysis showed that the proportion of CD161CD56 NK cells negatively correlated with white blood cells, Immunoglobulin A (IgA), IgM, IgG, European League Against Rheumatism Sjogren's Syndrome Patient Reported Index and European League Against Rheumatism Sjogren's Syndrome Disease Activity Index, and positively correlated with complement C4. The proportion of CD161CD56 NK cells in pSS patients with decayed tooth, fatigue, arthralgia, skin involvement, primary biliary cirrhosis, interstitial lung disease, anti-SSA/Ro60 positive, anti-SSB positive and high IgG was lower than that in negative patients. Furthermore, compared with inactive patients, the proportion of CD161CD56 NK cells decreased obviously in active patients. The area under the curve was 0.7375 (p = .0016), the results indicated that CD161CD56 NK cells had certain diagnostic values for pSS. In addition, the proportion of CD86, HLA-DR, Ki67, FasL, TNF-α, and IFN-γ on CD161CD56 NK cells was lower than that on CD161CD56 NK cells in the peripheral blood of pSS patients.

CONCLUSION

This study suggested that the proportion of CD56 NK cells and CD161CD56 NK cells decreased significantly in pSS patients, and the proportion of CD161CD56 NK cells negatively associated with the clinical features and disease activity of pSS patients. CD161 expression inhibited the function of CD56 NK cells in peripheral blood of pSS patients. The CD161CD56 NK cells may present as a potential target for therapy and a biomarker of disease activity in pSS.