We report 14 cases of immune effector cell (IEC)-associated enterocolitis following chimeric antigen receptor T-cell (CAR-T) therapy in multiple myeloma, with a 1.2% incidence overall (0.2% for idecabtagene vicleucel and 2.2% for ciltacabtagene autoleucel). Patients developed acute-onset symptoms (typically non-bloody Grade 3+ diarrhea) with negative infectious workup beginning a median of 92.5 days (range: 22–210 days) after CAR-T therapy and a median of 85 days after cytokine release syndrome resolution. Gut biopsies uniformly demonstrated inflammation, including intra-epithelial lymphocytosis and villous blunting. In one case where CAR-specific immunofluorescence stains were available, CAR T-cell presence was confirmed within the lamina propria. Systemic corticosteroids were initiated in 10 patients (71%) a median of 25.5 days following symptom onset, with symptom improvement in 40%. Subsequent infliximab or vedolizumab led to improvement in 50% and 33% of corticosteroid-refractory patients, respectively. Five patients (36%) have died from bowel perforation or treatment-emergent sepsis. In conclusion, IEC-associated enterocolitis is a distinct but rare complication of CAR-T therapy typically beginning 1–3 months after infusion. Thorough diagnostic workup is essential, including evaluation for potential T-cell malignancies. The early use of infliximab or vedolizumab may potentially hasten symptom resolution and lower reliance on high-dose corticosteroids during the post-CAR-T period.

我们报道了 14 例多发性骨髓瘤嵌合抗原受体 T 细胞 （CAR-T） 治疗后免疫效应细胞 （IEC） 相关小肠结肠炎，总体发病率为 1.2% （idecabtagene vicleucel 为 0.2%，ciltacabtagene autoleucel 为 2.2%）。患者出现急性发作症状（通常为非血性 3+ 级腹泻）且感染性病情检查阴性，中位时间为 CAR-T 治疗后 92.5 天 （范围：22-210 天），中位细胞因子释放综合征消退后 85 天。肠道活检一致显示炎症，包括上皮内淋巴细胞增多和绒毛钝化。在一例 CAR 特异性免疫荧光染色可用的病例中，证实了固有层内存在 CAR T 细胞。10 例患者 （71%） 开始全身性皮质类固醇治疗，中位症状出现后 25.5 天，40% 的症状改善。随后的英夫利昔单抗或维多珠单抗分别导致 50% 和 33% 的皮质类固醇难治性患者得到改善。5 例患者 （36%） 死于肠穿孔或治疗中出现的脓毒症。总之，IEC 相关小肠结肠炎是 CAR-T 治疗的一种独特但罕见的并发症，通常在输注后 1-3 个月开始。全面的诊断性病情检查是必不可少的，包括评估潜在的 T 细胞恶性肿瘤。在 CAR-T 后时期，早期使用英夫利昔单抗或维多珠单抗可能会加速症状缓解并降低对大剂量皮质类固醇的依赖。