To investigate the expression and role of regulatory plasma cells in gravidas with systemic lupus erythematosus (SLE).

Gravidas with SLE were enrolled in Henan Provincial People′s Hospital from April 2013 to April 2018. They were divided into three groups including pregnancy control group, SLE stable group and SLE deterioration group. The ratio of CD3-LAG-3+ CD138^high regulatory plasma cells was detected by flow cytometry. The concentrations of soluble human leukocyte antigen-G (sHLA-G) and anti-nuclear antibody Ig were detected by ELISA. Lymphocytes in peripheral blood of SLE deterioration group were isolated, and then cultured in RPMI1640 medium containing 10% fetal bovine serum and stimulated with HLA-G.

Flow cytometry showed that the proportion of regulatory plasma cells in SLE stable group was (2.483±0.131 8)% and that in SLE deteriorating group was (1.662±0.130 4)%. There was a significant difference between the two groups (t=4.431, P=0.001 3). The concentrations of sHLA-G in SLE stable group and SLE deteriorating group were (36.50±3.510) ng/ml and (16.50±2.405) ng/ml, and the difference between the two groups was statistically significant (t=4.701, P=0.000 8). Correlation analysis showed that the concentration of sHLA-G was positively correlated with the proportion of regulatory plasma cells (r=0.747 1, P=0.000 9). The results of in vitro experiment showed that the proportions of B cells and regulatory plasma cells were (7.573±0.653 9)% and (1.593±0.187 9)% in SLE deterioration group and (3.732±0.717 8)% and (2.503±0.292 1)% in HLA-G group with statistical differences between the two groups (t=3.957, P=0.002 7; t=2.620, P=0.025 6).

The proportion of regulatory plasma cells and the concentration of sHLA-G were significantly decreased in pregnant patients with SLE, which was closely related to disease severity. HLA-G played an important role in promoting the proliferation of regulatory plasma cells.

Regulatory plasma cell; Systemic lupus erythematosus; Pregnancy; HLA-G