Objective: We observed and compared the differences in immune reconstruction between single-infusion anti-B-cell maturation antigen (BCMA) , chimeric antigen receptor T cells (CAR-T) , and combined infusion of anti-CD19 CAR-T cells in the treatment of recurrent/refractory multiple myeloma (RRMM) . Methods: Sixty-one patients with RRMM who underwent CAR-T cell therapy in our hospital from June 2017 to December 2020 were selected. Among them, 26 patients received anti-BCMA target, and 35 patients received anti-BCMA combined with anti-CD19 target. Using flow cytometry, we determined T cell subsets (CD3(+), CD4(+), CD8(+), CD4(+)/CD8(+)) , B cells (CD19(+)) , and NK cells (CD16(+) CD56(+)) at different time points before and after CAR-T treatment, and detected immunoglobulin IgG, IgA and IgM levels by immunoturbidimetry. We compared the reconstruction rules of lymphocyte subsets and immunoglobulins in the two groups. Results: CD8(+) T lymphocytes recovered most rapidly after the infusion of CAR-T cells, returning to pre-infusion levels at 3 months and 1 month after infusion, respectively[BCMA: 695 (357, 1264) /μl vs 424 (280, 646) /μl; BCMA+CD19: 546 (279, 1672) /μl vs 314 (214, 466) /μl]. NK cells returned to normal levels at 3 months after infusion in both groups[BCMA: 171 (120, 244) /μl, BCMA+CD19: 153 (101, 218) /μl (Normal reference range 150-1100/μl) ]; however, the NK cells were not maintained at stable levels in the BCMA CAR-T cells group. The recovery of CD4(+) T lymphocytes in both groups was slow and remained persistently low within 12 months after infusion, and no recovery was observed in most patients. The reversal of the ratio of CD4(+)/CD8(+) lasted for more than a year. The levels of CD19(+) B cells in both groups returned to baseline 3 months after infusion[BCMA: 62 (10, 72) /μl vs 57 (24, 78) /μl; BCMA+CD19: 40 (4, 94) /μl vs 29 (14, 46) /μl]. IgG returned to the pre-infusion level 12 months after infusion in the group with anti-BCMA cells alone, but not in the group with combined infusion of CD19 CAR T cells[7.82 (6.03, 9.64) g/L vs 6.92 (4.62, 12.76) g/L]. IgA returned to pre-infusion levels at 9 and 12 months after infusion, respectively[BCMA: 0.46 (0.07, 0.51) g/L vs 0.22 (0.12, 4.01) g/L; BCMA+CD19: 0.46 (0.22, 0.98) g/L vs 0.27 (0.10, 0.53) g/L]. IgM in both groups returned to pre-infusion levels 6 months after infusion[BCMA: 0.43 (0.06, 0.60) g/L vs 0.20 (0.13, 0.37) g/L; BCMA+CD19: 0.53 (0.10, 0.80) g/L vs 0.16 (0.11, 0.28) g/L]. There was no significant difference in the indexes of lymphocyte subpopulation reconstruction and immunoglobulin recovery between the two groups at each time point. Conclusion: This study showed that in patients with RRMM treated with CAR-T cells, the appropriate target antigen can be selected without considering the difference of immune reconstruction between anti-BCMA CAR-T and combined anti-CD19 CAR-T therapy.
目的： 观察比较单纯输注抗B细胞成熟抗原（BCMA）嵌合抗原受体T细胞（CAR-T细胞）与输注抗BCMA联合抗CD19 CAR-T细胞治疗复发/难治性多发性骨髓瘤（RRMM）患者免疫重建的差异。 方法： 以2017年6月至2020年12月在我院行CAR-T细胞治疗的61例RRMM患者为研究对象，其中单纯接受抗BCMA靶点者26例，接受抗BCMA联合抗CD19靶点者35例。流式细胞术分别测定CAR-T治疗前后不同时间点的T细胞亚群（CD3(+)、CD4(+)、CD8(+)、CD4(+)/CD8(+)）、B细胞（CD19(+)）及NK细胞（CD16(+)CD56(+)），免疫比浊法检测免疫球蛋白IgG、IgA及IgM水平。对比两组淋巴细胞亚群及免疫球蛋白的重建规律。 结果： CAR-T细胞输注后，CD8(+) T淋巴细胞恢复最快，BCMA组与BCMA+CD19组分别在输注后3个月和输注后1个月时恢复至输注前水平[BCMA：695（357, 1264）个/μl对424（280, 646）个/μl；BCMA+CD19：546（279, 1672）个/μl对314（214, 466）个/μl]。两组NK细胞均在输注后3个月时恢复至正常水平[分别为171（120, 244）个/μl、153（101, 218）个/μl（正常参考范围150~1100个/μl）]，但BCMA组不能维持在稳定水平。两组CD4(+) T淋巴细胞恢复缓慢，输注后12个月内仍处于持续低水平，多数患者未观察到恢复。CD4(+)/CD8(+)比值倒置持续1年以上。两组CD19(+) B细胞均在输注后3个月恢复至输注前水平[BCMA：62（10, 72）个/μl对57（24, 78）个/μl；BCMA+CD19：40（4, 94）个/μl对29（14, 46）个/μl]。BCMA组IgG在输注后12个月恢复至输注前水平[7.82（6.03, 9.64）g/L对6.92（4.62, 12.76）g/L]，BCMA+CD19组未恢复。IgA先后在输注后9个月和12个月恢复至输注前水平[BCMA：0.46（0.07, 0.51）g/L对0.22（0.12, 4.01）g/L；BCMA+CD19：0.46（0.22, 0.98）g/L对0.27（0.10, 0.53）g/L]。两组IgM在输注后6个月恢复至输注前水平[BCMA：0.43（0.06, 0.60）g/L对0.20（0.13, 0.37）g/L；BCMA+CD19：0.53（0.10, 0.80）g/L对0.16（0.11, 0.28）g/L]。两组患者淋巴细胞亚群重建及免疫球蛋白恢复在各时间点的差异均无统计学意义。 结论： 在接受CAR-T细胞治疗的RRMM患者中，可基本不考虑单纯抗BCMA CAR-T与抗BCMA联合抗CD19 CAR-T治疗之间免疫重建的差异而选择合适的靶抗原。 中国临床试验注册中心：： ChiCTR-OIC-17011271、ChiCTR-OIC-17011272.
Keywords: Chimeric antigen receptor T cells; Immune reconstruction; Multiple myeloma.