目的 研究系统性红斑狼疮（systemic lupus erythematosus, SLE）患儿体内B1细胞和滤泡辅助性T细胞（follicular helper T cell, Tfh）水平，探讨间充质干细胞（mesenchymal stem cell, MSC）能否调控SLE患儿外周血中B1细胞和Tfh细胞水平。 方法 分离并检测SLE患儿及对照组外周血单个核细胞（peripheral blood mononuclear cell, PBMC）中的B1细胞、Tfh细胞，并分析两组间细胞差异，以及SLE患儿细胞群与临床指标的相关性。人脐带间充质干细胞（human umbilical cord mesenchymal stem cell, hUCMSC）与PBMC按照PBS对照组、hUCMSC∶PBMC（1∶10）组、hUCMSC∶PBMC（1∶20）组共培养48 h，再次检测培养后B1细胞、Tfh细胞比例。 结果 hUCMSC贴壁生长并呈梭形，生长良好，并成骨和成脂分化。B1细胞、Tfh细胞在SLE病人中，均高于对照组（P<0.05），但与血清补体、免疫球蛋白、抗体水平、系统性红斑狼疮疾病活动度评分等无显著相关性（P>0.05）。Tfh细胞与血清C4、IgM有相关性趋势。PBMC与hUCMSC共培养后，各组之间的B1细胞、Tfh细胞差异无统计学意义（P>0.05）。 结论 B1细胞和Tfh细胞在SLE组与对照组中数量有差异，可能参与了SLE的发展过程。hUCMSC可能不通过调控外周血中B1细胞和Tfh细胞数量对SLE发挥治疗作用。

Objective To investigate B1 cell and follicular helper T (Tfh) levels in children with systemic lupus erythematosus (SLE) and to assess whether mesenchymal stem cells (MSCs) regulate peripheral blood B1 cells and Tfh cells in pediatric SLE. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from children with SLE and from controls. B1 and Tfh cells were measured, differences between groups were analyzed, and correlations with clinical indices were evaluated. Human umbilical cord mesenchymal stem cells (hUCMSCs) were co-cultured with PBMCs for 48 hours at hUCMSC:PBMC ratios of 1:10 and 1:20, with PBS-treated PBMCs as control; post-culture proportions of B1 and Tfh cells were re-assessed. Results hUCMSCs adhered to plastic with spindle-shaped morphology, showed robust growth, and exhibited osteogenic and adipogenic differentiation. B1 and Tfh cell levels were higher in children with SLE than in controls (P<0.05) and were not significantly correlated with serum complement, immunoglobulins, antibody levels, or SLE Disease Activity Index scores (P>0.05). Tfh cells showed a trend toward association with serum C4 and IgM. After co-culture, no statistically significant differences in B1 or Tfh cell proportions were detected among the PBS control and hUCMSC co-culture groups (P>0.05). Conclusions B1 cells and Tfh cells differ between children with SLE and controls and may be involved in SLE pathogenesis. hUCMSCs do not appear to exert therapeutic effects in SLE by regulating peripheral blood B1 and Tfh cell numbers.