Changes and clinical significance of γδT cells and their major functional subsets in peripheral blood of patients with systemic lupus erythematosus

Objective To investigate the changes and clinical significance of γδT cells and their major functional subsets γδT1 and γδT17 cells in the peripheral blood of patients with systemic lupus erythematosus (SLE).

Methods Ratios and absolute numbers of γδT cells, γδT1 cells and γδT17 cells in peripheral blood were detected by flow cytometry in 21 SLE patients (SLE) group and 16 healthy controls (HC group). Correlations of γδT cells, γδT1 cells and γδT17 cells in the peripheral blood with clinical indicators were analyzed by Pearson correlation analysis.

Results In SLE patients, the percentage of γδT cells to lymphocytes in the peripheral blood was (2.30±1.10)%, which was significantly lower than (3.30±1.51)% in the HC group (P < 0.05); the percentage of γδT1 cells to lymphocytes in peripheral blood was (0.93±0.67)%, which was significantly lower than (2.09±1.21)% in the HC group (P < 0.001); the ratio of γδT17 cells to lymphocytes in the peripheral blood was (1.53±2.82)‰, which showed an increasing trend when compared to (0.18±0.12)‰ in the HC group (P>0.05). The absolute number of γδT cells in the peripheral blood in SLE patients was (2.88±2.18)×10⁴/mL, which was significantly lower than (7.96±3.96)×10⁴/mL in the HC group (P < 0.000 1); the absolute number of γδT1 cells in the peripheral blood in SLE patients was (1.20±1.17)×10⁴/mL, which was significantly lower than (5.05±3.04)×10⁴/mL in the HC group (P < 0.000 1); the absolute number of γδT17 cells in the peripheral blood in SLE patients was (1.03±1.08)×10³/mL, which was significantly higher than (0.40±0.24)×10³/mL in the HC group (P < 0.05). The proportion of γδT17 cells in the peripheral blood of SLE patients was positively correlated with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) (r=0.59, P < 0.01) and erythrocyte sedimentation rate (r=0.65, P < 0.01), while the absolute number of γδT17 cells was positively correlated with the SLEDAI score (r=0.59, P < 0.01) and negatively correlated with the complement C3 level (r=-0.53, P < 0.05).

Conclusion The significant decrease in the number of γδT cells in the peripheral blood of SLE patients is mainly due to the reduction of its γδT1 cell subset; γδT17 cells play an important role in the pathogenesis and activity of SLE.