Fig. 1

Peripheral NK cell deficiency was associated with disease activity in treatment-naive SLE patients. A The percentage of NK cells in untreated SLE patients (n = 156), untreated RA patients (n = 22) and HCs (n = 30). B The absolute number of peripheral NK cells in untreated SLE patients (n = 156), untreated RA patients (n = 22) and HCs (n = 30). C Correlation of the NK count with the level of C3 in SLE patients. D Correlation of the NK count with the level of PLT in SLE patients. E Correlation of the NK count with SLEDAI score in SLE patients. F Comparison of the absolute number of peripheral NK cells in SLE patients with mild activity (SLEDAI < 10) (n = 97) and moderate-high activity (SLEDAI ≥ 10) (n = 59). G Comparison of the absolute number of peripheral NK cells in SLE patients with (n = 74) and without LN (n = 82). H Comparison of the absolute number of peripheral NK cells in SLE patients with (n = 112) and without hemocytopenia (n = 44). (* P < 0.05, **P < 0.01, ***P < 0.001). C3: serum concentrations of complement C3; PLT: blood platelet; SLEDAI: Systemic Lupus Erythematosus Disease Activity Index; LN: lupus nephritis